AudioCircle
Industry Circles => GIK Acoustics => Topic started by: MONKEYWICKEDMONKEY on 21 Aug 2020, 06:04 pm
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My room is an open room. Its bad for bass. So I bought 2 subs (Rythmik L12's). Using AudioTools (iPhone) and the Dayon calibrated mic I started running sweeps.
Room
https://i.imgur.com/f9EP4xH.jpg
Sub behind couch (main listening position)
(https://www.audiocircle.com/image.php?id=213526)
Sub on front wall in top left corner
(https://www.audiocircle.com/image.php?id=213527)
The plots are subs only, no mains. Suggestions on where else to try to place them? I recently tried inside the right speaker and the first sweep I did was excellent but subsequent sweeps looked more like these.
Does volume make a difference?
Also, is there a treatment that would also help with this?
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The bottom graph looks better than the top. Keep in mind we're only really concerned from teh crossover frequency on down, usually around 80Hz or so. What it does above there is less critical.
If you have 2 subs, there are some strategies you can use to use cancellations in your favor to get a flatter response. Details in this article on my blog (http://www.gikacoustics.com/room-setup-speaker-placement-201-part-two-subwoofers/).
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Thanks, yeah I have been trying those out as best I can. I have the subs set at 60hz with a 12db slope. Front wall phase at 0 and rear wall at 180.
Given my room, some of the strategies aren't workable. Whats weird is they all look super similar. No matter what I do so I wondered about treatments.
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Experiment with placement. A sub behind a couch doesn't seem like a viable option. Try both subs near the front wall.
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I agree with others that you'll have to experiment. James's link gives some ideas. I also agree that the 2nd graph looks better.
According the the Rhythmik site, your subs have continuously variable phase controls. Good! In evaluating a setup, run a full-range sweep (mains + subs) with the mic at the main listening position, and adjust the phase control for smoothest response around the crossover frequency.
This is really important to get the main and sub speakers working with, not against, one another. Using stereo subs, I do this for each channel individually. You can check later with a mono sweep to see what that looks like, if you want.
P.S. Try different sub xover frequencies and slopes. Measure and listen. In my experience, shallower slopes can measure better but sound worse. The effects of changing xover frequency I find a bit unpredictable.
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I agree with others that you'll have to experiment. James's link gives some ideas. I also agree that the 2nd graph looks better.
According the the Rhythmik site, your subs have continuously variable phase controls. Good! In evaluating a setup, run a full-range sweep (mains + subs) with the mic at the main listening position, and adjust the phase control for smoothest response around the crossover frequency.
This is really important to get the main and sub speakers working with, not against, one another. Using stereo subs, I do this for each channel individually. You can check later with a mono sweep to see what that looks like, if you want.
P.S. Try different sub xover frequencies and slopes. Measure and listen. In my experience, shallower slopes can measure better but sound worse. The effects of changing xover frequency I find a bit unpredictable.
When you say Crossover frequency, you mean the sub's cross over? mains?
Thanks. The mains (Klipsch Heresy 4's) roll off at 48hz so I had been sting in the low 50's but at 60 and even 70 I get much more. I did run sweeps with all mains and subs and honestly they look like the 1st graph. Hump at 44hz then dives down around 63 and then back up at around 125. I moved the rear sub to half way along the left side wall and set the phase at 90, then 45, then 135 and they all basically looked the same. As of this morning they are both on the front wall and it all seems more cohesive (could be placebo) but I have the same dips just in front of the listening position as I'm sure its all bounsing off the wall behind me (18" back or so). Also I noticed that the louder I do my sweeps the worse they get. My volume knob isn't marked so thats going to be an issue.
I guess I'm running out of ideas being as the right side of the room is way open (though there's good, not bloated bass in the dining area). Also, to the listener's right of the couch in front of the hallway opening there's ridiculous bass. Like huge bass there. So I was thinking some treatment on the back wall. So many rabbit holes....
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You can also try the sub crawl trick where you place the sub at the listening position and crawl around the room to find the best sub position.
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You can also try the sub crawl trick where you place the sub at the listening position and crawl around the room to find the best sub position.
I started with that which is how I ended up with the front left corner and rear by the listening position.
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When you say Crossover frequency, you mean the sub's cross over? mains?
Thanks. The mains (Klipsch Heresy 4's) roll off at 48hz so I had been sting in the low 50's but at 60 and even 70 I get much more. I did run sweeps with all mains and subs and honestly they look like the 1st graph. Hump at 44hz then dives down around 63 and then back up at around 125. I moved the rear sub to half way along the left side wall and set the phase at 90, then 45, then 135 and they all basically looked the same. As of this morning they are both on the front wall and it all seems more cohesive (could be placebo) but I have the same dips just in front of the listening position as I'm sure its all bounsing off the wall behind me (18" back or so). Also I noticed that the louder I do my sweeps the worse they get. My volume knob isn't marked so thats going to be an issue.
I guess I'm running out of ideas being as the right side of the room is way open (though there's good, not bloated bass in the dining area). Also, to the listener's right of the couch in front of the hallway opening there's ridiculous bass. Like huge bass there. So I was thinking some treatment on the back wall. So many rabbit holes....
I thought you are running the mains full-range and using a low-pass filter for the subs. So what I meant was changing that frequency to see what setting gets the smoothest FR.
Yes, rabbit holes! Hooking up subs is not trivial, especially if you care about even FR and not just boom. Many users prefer to use a crossover for both mains and subs and possibly even DSP (manual or automatic PEQ) to smooth out the bass. But, especially if you are running an analog system, that entails more complication. I am not sure how far you want to go. Really far? Maybe something like a miniDSP SHD. A little? Maybe one of the cheaper miniDSP units. Very little? a graphic equalizer, used in the bass circuit only.
Bass traps do help FR a little, but in my experience, the main effect is to reduce overhang (ringing), which manifests as boominess.
Achieving even bass in in multiple positions in a domestic room is very difficult, if not impossible. Some who use 4 subs report better success. (Google "Swarm subwoofer system".) Without many subs, the best I've ever been able to get is even and smooth bass at the central listening position and close by.
FR = frequency response
PEQ = parametric equalization
DSP = digital signal processing
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I thought you are running the mains full-range and using a low-pass filter for the subs. So what I meant was changing that frequency to see what setting gets the smoothest FR.
Yes, rabbit holes! Hooking up subs is not trivial, especially if you care about even FR and not just boom. Many users prefer to use a crossover for both mains and subs and possibly even DSP (manual or automatic PEQ) to smooth out the bass. But, especially if you are running an analog system, that entails more complication. I am not sure how far you want to go. Really far? Maybe something like a miniDSP SHD. A little? Maybe one of the cheaper miniDSP units. Very little? a graphic equalizer, used in the bass circuit only.
Bass traps do help FR a little, but in my experience, the main effect is to reduce overhang (ringing), which manifests as boominess.
Achieving even bass in in multiple positions in a domestic room is very difficult, if not impossible. Some who use 4 subs report better success. (Google "Swarm subwoofer system".) Without many subs, the best I've ever been able to get is even and smooth bass at the central listening position and close by.
FR = frequency response
PEQ = parametric equalization
DSP = digital signal processing
Yes, you are correct, mains at full and the subs to fortify. OK I see what you are saying. One thing too is that I once set the subs to 120hz crossover and the graphs looked the same, which, I don't know. I'm definitely not above DSP but my reading suggests I need to get this handled first and then use DSP as the secret sauce?
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DSP will help even out the bass response at the main listening position.
I agree, do the best you can before adding DSP. But below 100 Hz or so, there is not a lot can be done with traps, unless they are extremely big and thick. Below 60 Hz or so, traps are pretty useless unless you use some kind of tuned absorber.
I always think, the big 4 things to address with acoustic treatment are- Slap echo - use enough absorption/diffusion to reduce it everywhere
- First reflections from sidewalls - kill them! and ceiling too if possible
- SBIR - to reduce this, position speakers so woofers are differing distances from side walls, front wall, ceiling, and floor.
- Bass trapping - will reduce boominess & improve intelligibility
But not everyone wants to do that much.
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Thanks. The mains (Klipsch Heresy 4's) roll off at 48hz so I had been sting in the low 50's but at 60 and even 70 I get much more.
When I read your reply, my first thought was "of course the graphs look so terrible, you are crossing over way too high." It's a subwoofer, not a mid-bass woofer.
My speakers roll off at 34 Hz, I have my sub set at 32 Hz. The frequency response is nice and flat. With a higher crossover you are adding bass to bass and as you have noticed the nodes are huge. Try setting the sub crossover lower, 45 Hz as a starting point, you may end up at 38 Hz. Subs work really well in corners, they use less power in a corner too, less power = less distortion.
Recommended reading:
Loudspeakers, Rooms, and Subwoofers - Audiophile Articles
https://www.audiocircle.com/index.php?topic=58304.0 (https://www.audiocircle.com/index.php?topic=58304.0)
The bottom of the first post has a link to the Harman Room Mode Calculator. The calculator will show you room modes, move your couch into a mode and get tons of bass. Right now your couch may be in a null which is why you want to bump up the crossover point for more oomph.
Videos - No reading required
How to set up a sub crossover
https://rel.net/how-to-set-the-crossover-on-your-subwoofer/ (https://rel.net/how-to-set-the-crossover-on-your-subwoofer/)
Tackling the Deep End: How to Set up a Subwoofer
https://www.youtube.com/playlist?list=PLaShG1I6_hHXPPWT05eHxYLb1d6SDYbxi (https://www.youtube.com/playlist?list=PLaShG1I6_hHXPPWT05eHxYLb1d6SDYbxi)
The procedures will work for all subs.
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Not to be contentious, and I know the suggestion to use a room mode calculator is being made to be helpful. Still, if you try it and it doesn't agree with what you actually measure in your room, you won't be alone. Frequently, such calculators are way off, because of construction materials, furniture, and similar factors. Yet, as @WGH suggests, worth a try.
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You can also try the sub crawl trick where you place the sub at the listening position and crawl around the room to find the best sub position.
That only works when you have 1 sub.
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I suggest that you set the measurements aside for a while and just listen. Your ears and common sense will tell you where the best locations in your room are. Afterwards, you can fine tune with measurements and settings.
Many of us place our stereo subs next to the front speakers. Start there.
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That only works when you have 1 sub.
What reference do you have for that. I'm only using one sub, SVS SB3000, but am considering a second. I set mine up using the sub crawl and was under the impression if I wanted to add a second I would use the crawl's second best location.
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When I read your reply, my first thought was "of course the graphs look so terrible, you are crossing over way too high." It's a subwoofer, not a mid-bass woofer.
My speakers roll off at 34 Hz, I have my sub set at 32 Hz. The frequency response is nice and flat. With a higher crossover you are adding bass to bass and as you have noticed the nodes are huge. Try setting the sub crossover lower, 45 Hz as a starting point, you may end up at 38 Hz. Subs work really well in corners, they use less power in a corner too, less power = less distortion.
Recommended reading:
Loudspeakers, Rooms, and Subwoofers - Audiophile Articles
https://www.audiocircle.com/index.php?topic=58304.0 (https://www.audiocircle.com/index.php?topic=58304.0)
The bottom of the first post has a link to the Harman Room Mode Calculator. The calculator will show you room modes, move your couch into a mode and get tons of bass. Right now your couch may be in a null which is why you want to bump up the crossover point for more oomph.
Videos - No reading required
How to set up a sub crossover
https://rel.net/how-to-set-the-crossover-on-your-subwoofer/ (https://rel.net/how-to-set-the-crossover-on-your-subwoofer/)
Tackling the Deep End: How to Set up a Subwoofer
https://www.youtube.com/playlist?list=PLaShG1I6_hHXPPWT05eHxYLb1d6SDYbxi (https://www.youtube.com/playlist?list=PLaShG1I6_hHXPPWT05eHxYLb1d6SDYbxi)
The procedures will work for all subs.
OMG. Setting it too high. I never would have thought of that and yet the graphs back it up. Wow. I feel dumb.
I’ll check the vids on a few , going to turn the crossover point down and listen to what’s happening. :idea: :idea:
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I suggest that you set the measurements aside for a while and just listen. Your ears and common sense will tell you where the best locations in your room are. Afterwards, you can fine tune with measurements and settings.
Many of us place our stereo subs next to the front speakers. Start there.
I have to remind myself that it’s a journey
And not a problem.
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Suggest reading Floyd Toole's "Sound Reproduction" 3rd edition, it is the consummate audiophile primer for understanding how speakers/subs interact in-room. Toole worked for the National (Canadian) Research Council for decades before retiring from Harmon International. He invented Spinorama, an anechoic testing method that predicts in-room speaker performance. He and other acousticians like Earl Geddes recommend multiple subs (3 or 4) to help control bass peaks/dips that are inherent to all residentially sized rooms. The Rythmik L12 is a very good choice for use in a multiple sub setup.
He would avoid putting subs side by side and especially all lined up along the front wall with the mains. Sound behaves as waves up to the transition (Schroeder frequency - roughly 300 Hz). If you think of a bathtub with 4 inches of water and moving your hand in the water back and forth from end to end, waves are created. As the waves hit the ends they bounce back where they meet the next wave and either double, cancel, or interfere with each other. Now imagine a second hand doing the same from from the side of the tub. The waves would still energize the water but at a more uniform way. So using side by side subs would just double the bass peaks/dips.
I have 3 subs in my 8ft x 13ft x 21ft room (could do 4 but 3 is enough). They are set up along the walls (where subs work best). One is fairly tight to the front right corner, one is about 2.5ft from the front left corner, and the last one is roughly midspan along the left side wall. My mains are 5.5 ft from the front wall and 1.5 ft from side walls, severely toed in, with the chair in the middle of the room (mid-field). Also have six 2ft x 4ft GIK 244 full range panels, four 2ft x 4ft GIK 244 bass traps, three tall open randomly filled bookcases on side walls to act as casual diffusers, and use <500 Hz Dirac room measurement/correction software. Found that 60 Hz crossover sounded better than 80 Hz.
Toole recommends getting the right speakers first, then adding room treatments for bass second, although in his own home he violated that to maintain better views from expansive windows which he accepted as a challenge. Third step would be bringing in the subs. Finally apply DSP, but always best to solve physical problems via physical means (quoted from Earl Geddes). BTW my room, done independently, is almost identical to Earl's and follows Fibonacci ratios, ala Cardas. Toole gives several examples of 4 sub setups in his book. One of the best is centering them on all four walls. Another good one was in each corner.
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Suggest reading Floyd Toole's "Sound Reproduction" 3rd edition, it is the consummate audiophile primer for understanding how speakers/subs interact in-room. ...
He would avoid putting subs side by side and especially all lined up along the front wall with the mains.
Setting both subs on the front wall next to the main speakers will react in the room in the same way as floor standing speakers that dig down deep, but few audiophiles would argue against the use of floor standers with low bass based on Toole's theories.
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As crazy as this may sound, sometimes reorienting subs to 'aim' in a different direction changes the way they load a room. I have a GR servo sub (similar design, slightly different driver) and had all sorts of headaches getting it to sound and measure well in my oddball room (sloping 14 foot ceilings, open on one side, etc). Just for grins I tried aiming it at the wall instead of into the room in the spot that sounded and measured best, and that simple move made it sound WAY more evenly balanced (less midbass peaks), and even seemed to give it a bit more VERY low bass extension. It measured better that way as well. Just a thought.
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What reference do you have for that. I'm only using one sub, SVS SB3000, but am considering a second. I set mine up using the sub crawl and was under the impression if I wanted to add a second I would use the crawl's second best location.
That could get close and may work. Just have to try it. I didn’t use it when I set up my 2 subs. Subs weigh too much. :D
What is not clear to me is what the original poster’s system is. Are we dealing with stereo bass or summed mono bass? If it is summed mono bass what equipment are they using? With stereo subs they should be near the mains for best blending in with the mains. This is often the worst place in the to put them to get even bass in the room. Opposite corners or opposite side walls are better for more even bass throughout the room with mono bass. I have 2 Rythmik F15HPs running off my AVR sub output. One is in the front of the room between the TV and the right speaker. The other is in the back of the room a couple of feet from the corner. The bass appears evenly distributed to me. Someday I will get around to measuring the response for use with my 2 channel system which will have DSP controlled subs.
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As crazy as this may sound, sometimes reorienting subs to 'aim' in a different direction changes the way they load a room. I have a GR servo sub (similar design, slightly different driver) and had all sorts of headaches getting it to sound and measure well in my oddball room (sloping 14 foot ceilings, open on one side, etc). Just for grins I tried aiming it at the wall instead of into the room in the spot that sounded and measured best, and that simple move made it sound WAY more evenly balanced (less midbass peaks), and even seemed to give it a bit more VERY low bass extension. It measured better that way as well. Just a thought.
This is a great example of experimenting to find what works best for you.
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That could get close and may work. Just have to try it. I didn’t use it when I set up my 2 subs. Subs weigh too much. :D
What is not clear to me is what the original poster’s system is. Are we dealing with stereo bass or summed mono bass? If it is summed mono bass what equipment are they using? With stereo subs they should be near the mains for best blending in with the mains. This is often the worst place in the to put them to get even bass in the room. Opposite corners or opposite side walls are better for more even bass throughout the room with mono bass. I have 2 Rythmik F15HPs running off my AVR sub output. One is in the front of the room between the TV and the right speaker. The other is in the back of the room a couple of feet from the corner. The bass appears evenly distributed to me. Someday I will get around to measuring the response for use with my 2 channel system which will have DSP controlled subs.
You’re right, I never did put system details. I must have spaced it.
The system is 2 channel stereo
Mains: Klipsch Heresy IV
Subs: Rythmik L12 running stereo via RCA from the preamp. But I can run summed, whatever works best.
Power amp: Odyssey Khartago Stereo
Preamp: Quicksilver Audio Linestage Preamp (4 outputs)
In regards to the suggestion about aiming the subs I did find a forum post about perpendicular aiming of subs relative to the listening position and am playing with that while both subs are on the front wall. When I had 1 sub behind d the listening position I tried aiming it straight at the wall and it didn’t measure any different but it was also very near field so I’ll try that too from the front wall.
Also i went and dropped the crossover to 40hz and did a little listening, mostly Mingus, but today I’ll run the gamut (Napalm Death, Trepaneringsritualen, King Tubby, PJ Harvey, etc).
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Huh? 4 outputs? Do you mean 4 pair of inputs? :scratch:
Also, IIRC the QS linestage has only one pair of RCA outputs, which I assume you run into your power amp. So how are you also able to connect your subs low-level via RCA? :scratch:
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Huh? 4 outputs? Do you mean 4 pair of inputs? :scratch:
Also, IIRC the QS linestage has only one pair of RCA outputs, which I assume you run into your power amp. So how are you also able to connect your subs low-level via RCA? :scratch:
4 outputs meaning 2 stereo pair. I had Mike Sanders turn the tape outs into main outs when I bought it.
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Gotcha. Thanks. :thumb:
I also have a pair of subs and get confused when connecting them to line stage w/ RCA I/C.....
(my line stage also has 2 pair of RCA outputs)
do you simply run one IC into each of the subs?
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Gotcha. Thanks. :thumb:
I also have a pair of subs and get confused when connecting them to line stage w/ RCA I/C.....
(my line stage also has 2 pair of RCA outputs)
do you simply run one IC into each of the subs?
It’s all good. I appreciate the time and all suggestions. Yes, I run red to the right and then a splitter into the low level inputs then white to the left also with a splitter.
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So as I understand it you are connecting the right channel into one sub and the left channel into the other sub. So you have stereo bass. I would try them both up by your mains and see how that is. Also need to play around with your crossover setpoint to get them to blend well. Since you aren't high passing your mains, you should be on the lower end of the crossover range.
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...today I’ll run the gamut (Napalm Death, Trepaneringsritualen, King Tubby, PJ Harvey, etc).
New subs bring out the 16 year old in all of us. It will take a couple of months before the newness wears off, then you will slowly realize that every song has big thumping bass like it is being played through Cerwin Veva speakers. Once a sub is adjusted properly you will never hear it, music flows from 20 Hz and up without calling attention to itself. It seems like once a month I get down and listen to the sub wondering "is this thing on?" It always is, I have just been playing music without any deep bass.
You will also discover music with 25 Hz bass like Cowboy Junkies "Trinity Sessions" and David Crosby latest "Hear If You Listen". You will also discover anemic rock and roll with no deep bass at all. If you want to tax your system and maybe break something try the "Blade Runner 2049" soundtrack by Hans Zimmer with really deep bass down to 15 Hz. I just know you are running the subs volume too high so before playing Blade Runner reduce the subs volume by 1/2, trust me on this. Your Klipsch 12" drivers will not be making sound but flapping like they are trying to fly.
(https://www.audiocircle.com/image.php?id=200278&size=large)
The Ultimate List of BASS in Movies w/ Frequency Charts
https://www.avsforum.com/threads/the-ultimate-list-of-bass-in-movies-w-frequency-charts.2763785/ (https://www.avsforum.com/threads/the-ultimate-list-of-bass-in-movies-w-frequency-charts.2763785/)
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New subs bring out the 16 year old in all of us. It will take a couple of months before the newness wears off, then you will slowly realize that every song has big thumping bass like it is being played through Cerwin Veva speakers. Once a sub is adjusted properly you will never hear it, music flows from 20 Hz and up without calling attention to itself. It seems like once a month I get down and listen to the sub wondering "is this thing on?" It always is, I have just been playing music without any deep bass.
You will also discover music with 25 Hz bass like Cowboy Junkies "Trinity Sessions" and David Crosby latest "Hear If You Listen". You will also discover anemic rock and roll with no deep bass at all. If you want to tax your system and maybe break something try the "Blade Runner 2049" soundtrack by Hans Zimmer with really deep bass down to 15 Hz.
(https://www.audiocircle.com/image.php?id=200278&size=large)
The Ultimate List of BASS in Movies w/ Frequency Charts
https://www.avsforum.com/threads/the-ultimate-list-of-bass-in-movies-w-frequency-charts.2763785/ (https://www.avsforum.com/threads/the-ultimate-list-of-bass-in-movies-w-frequency-charts.2763785/)
I don’t mind a touch of “bump” or “thump” but no boom. Yes, most of my music is bumpy/thumpy so I’m trying to find a good middle ground. The relatively small amount of boomer jazz means less priority but I do want to get the detail from stand up bass as best I can as well. I’m not looking for ruler flat, but within 5-8 hz would indicate I am getting the best of what I have in this terrible room.
As for bass music, I have a Scorn record with bass so low my mains’ woofers didn’t move but the sub could make milkshakes. Bass lines at 14-22hz, window rattling stuff. I’ve spent so much money (relatively speaking) on this system so far that I want everything to be put in a position to do its best job.
:thumb:
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So as I understand it you are connecting the right channel into one sub and the left channel into the other sub. So you have stereo bass. I would try them both up by your mains and see how that is. Also need to play around with your crossover setpoint to get them to blend well. Since you aren't high passing your mains, you should be on the lower end of the crossover range.
Thanks and yes you are correct. Right now they are inside the mains and crossed at 40hz / 12db slope. I did flip one (right) to some into the dining room to see if I hear a diff. But yeah originally I was aiming for opposite walls at opposite ends of the room to distribute the bass and hopefully fill in the holes.
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It’s all good. I appreciate the time and all suggestions. Yes, I run red to the right and then a splitter into the low level inputs then white to the left also with a splitter.
Sorry, I'm slightly confused....
What does the splitter do? Does it turn the single male RCA connector (at the sub end) into two male connectors, for input into the sub's L / R inputs?
If so, I've been doing it wrong! :duh:
For each of my subs, I've been running a single RCA IC from preamp to sub with only one male connector on each end. On the sub end I just plug it into either the L or R input. I get output from the sub but it's much diminished compared to running a pair of L / R IC into it.
Is this the type of splitter you use?
(https://images.crutchfieldonline.com/ImageHandler/trim/620/378/products/2013/38/119/g119iLJRY1F-F.jpg)
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Sorry, I'm slightly confused....
What does the splitter do? Does it turn the single male RCA connector (at the sub end) into two male connectors, for input into the sub's L / R inputs?
If so, I've been doing it wrong! :duh:
For each of my subs, I've been running a single RCA IC from preamp to sub with only one male connector on each end. On the sub end I just plug it into either the L or R input. I get output from the sub but it's much diminished compared to running a pair of L / R IC into it.
Is this the type of splitter you use?
(https://images.crutchfieldonline.com/ImageHandler/trim/620/378/products/2013/38/119/g119iLJRY1F-F.jpg)
Correct. As I understand it this adds 6db of gain so it’s probably not critical. I had them on hand so I use them.
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Oh, OK. Thanks.
You think it's OK running them as I do? Is it just a matter of turning up the sub's gain control to compensate for the lost output (which is what I do), or is there something lost in the signal with my setup?
PS: sorry for the sidetrack
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Oh, OK. Thanks.
You think it's OK running them as I do? Is it just a matter of turning up the sub's gain control to compensate for the lost output (which is what I do), or is there something lost in the signal with my setup?
PS: sorry for the sidetrack
Hahahaha, I’m the last person you should ask :lol: :lol:
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Update: no frequency sweeps but it sounds much more controlled although less bass than I’d like. I should be able to run a few sweeps tomorrow.
When sitting at the listening position my head is about 18” from the back wall and I feel like I’m getting some cancellation. If I sat all the way back on the couch I get very low bass though it lacks some punch. If I lean forward the low frequencies seem to drop out but there’s a decent amount of mid bass. I pulled a chair and moved the coffee table so that I’m now sitting the depth of the couch in front of the couch and it’s mostly all midbass save for of the really boomy albums.
Thoughts?
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Part of the reason I run Roon is they have a pretty good digital EQ that lets me manage the most obnoxious parts of the bass in my upstairs system.
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I had good results with the Dspeaker Antimode 8033s wich is made for stereo/dual subs. It’s very simple to use and goes between the preamp and sub amp. You can place your subs where you want, put the supplied microphone at your listening position, and run the sweeps. Simple and effective.
http://www.dspeaker.com/en/products/anti-mode-8033.shtml
Can be purchased here: https://www.underwoodhifi.com/products/dspeaker
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Hope everyone had a good weekend.
I did some sweeps with the subs crossed at 36hz. I did both 12 and 24db slopes. Not too much difference. I feel like 44hz is a room thing. Seems to always be there.
Both subs on the front wall. The right sub is facing right, left sub facing straight ahead.
12db slope
(https://www.audiocircle.com/image.php?id=213663)
24db slope.
(https://www.audiocircle.com/image.php?id=213664)
The volume was not changed so I cannot understand the difference in volume. That’s a mystery to my ignorance.
So I feel like I should go back to the 12db slope and acknowledge the 44hz peak but look past it and bring up that trough above it. What’s going on at 125 I have no idea. 63hz is always the low point in that part of the frequency range. No idea what to do about that either. Maybe this is the point where I run the full
Frequency sweep and then play with reflections and then dive into a mini DSP?
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I did some sweeps with the subs crossed at 36hz. I did both 12 and 24db slopes. Not too much difference. I feel like 44hz is a room thing. Seems to always be there.
Both subs on the front wall. The right sub is facing right, left sub facing straight ahead.
12db slope
(https://www.audiocircle.com/image.php?id=213663)
24db slope.
(https://www.audiocircle.com/image.php?id=213664)
The volume was not changed so I cannot understand the difference in volume. That’s a mystery to my ignorance.
So I feel like I should go back to the 12db slope and acknowledge the 44hz peak but look past it and bring up that trough above it. What’s going on at 125 I have no idea. 63hz is always the low point in that part of the frequency range. No idea what to do about that either. Maybe this is the point where I run the full frequency sweep and then play with reflections and then dive into a mini DSP?
I've missed a few posts. Did you adjust phase before making each graph? That is absolutely critical before looking at peaks and dips -- it will change them. And are the graphs of one channel (R or L)? I would look at each channel separately before thinking about a mono sweep.
To me, the 12 dB results look smoother. The sub is helping fill in the dip around 60 Hz.
To get a better picture of what's going on at 120 Hz, I'd run the sweep higher, to 300 Hz or even 500 Hz, well above the Schroeder frequency. It's a more holistic look at things, especially since by 160 Hz the 24 dB/octave graph is way down. That could be an artifact of reaching the end of a smoothed graph or it could be real. It would be good to know.
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In your room, your mains are starting to fall off by 100hz. If play with crossing the subs higher and then play with the level to find the sweet spot where you can use eq just for the peaks.
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That peak at 125 Hz is on your first graphs too, now that the sub crossover is lower it is easier to see.
(https://www.audiocircle.com/image.php?id=213527)
Have you run the sweeps without the subs? The peak may be the Klipsch's.
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That peak at 125 Hz is on your first graphs too, now that the sub crossover is lower it is easier to see.
Have you run the sweeps without the subs? The peak may be the Klipsch's.
I second that suggestion. A full-range sweep of the mains alone would be a useful baseline. I'm hoping their response really doesn't drop by 10 dB from 100 Hz to 200 Hz (unless you like a very warm sound).
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I've missed a few posts. Did you adjust phase before making each graph? That is absolutely critical before looking at peaks and dips -- it will change them. And are the graphs of one channel (R or L)? I would look at each channel separately before thinking about a mono sweep.
To me, the 12 dB results look smoother. The sub is helping fill in the dip around 60 Hz.
To get a better picture of what's going on at 120 Hz, I'd run the sweep higher, to 300 Hz or even 500 Hz, well above the Schroeder frequency. It's a more holistic look at things, especially since by 160 Hz the 24 dB/octave graph is way down. That could be an artifact of reaching the end of a smoothed graph or it could be real. It would be good to know.
Hi Mike, phase on both is set to 0 (as they are both on the front wall). I stop the sweep around 130 or so as I’ve only been interested in readings up to 125hz for now. So that’s why it gets squirrelly above that.
I will re-run the sweeps higher :thumb:
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In your room, your mains are starting to fall off by 100hz. If play with crossing the subs higher and then play with the level to find the sweet spot where you can use eq just for the peaks.
I tried this before and the huge bump at 44 hz shook the room. Only recently I started peeling back to the 30’s.
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That peak at 125 Hz is on your first graphs too, now that the sub crossover is lower it is easier to see.
(https://www.audiocircle.com/image.php?id=213527)
Have you run the sweeps without the subs? The peak may be the Klipsch's.
I have but I will re-run then again :thumb:
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I second that suggestion. A full-range sweep of the mains alone would be a useful baseline. I'm hoping their response really doesn't drop by 10 dB from 100 Hz to 200 Hz (unless you like a very warm sound).
I will re-run them sweeps with mains only tomorrow :thumb:
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Hi Mike, phase on both is set to 0 (as they are both on the front wall).
Yes, that is logical . . . but unless it's based on adjusting phase as you look at frequency response, it's probably wrong.
The sub has a crossover, which likely has some latency. The subs are on the front wall . . . are the mains on the front wall, too?
If there is any time or path-length difference between the subs and the mains, relative to the main listening position, there will be cancellation and enhancement at frequencies centered around the crossover frequency. And that will affect your response curve in a major way. If you have not yet set phase that way, you may be able to get better -- possibly much better -- results by doing so.
The effects of this are minimized by some audiophiles, simply because not all subs have a phase control. Bad reason! It's like the old joke about the drunk looking for his keys under the lamp post. "Where did you lose them?" "Over there -- but the light's better here."
Sorry to be a broken record. Trying to fix frequency response without optimizing phase is wasting your time.
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Yes, that is logical . . . but unless it's based on adjusting phase as you look at frequency response, it's probably wrong.
The sub has a crossover, which likely has some latency. The subs are on the front wall . . . are the mains on the front wall, too?
If there is any time or path-length difference between the subs and the mains, relative to the main listening position, there will be cancellation and enhancement at frequencies centered around the crossover frequency. And that will affect your response curve in a major way. If you have not yet set phase that way, you may be able to get better -- possibly much better -- results by doing so.
The effects of this are minimized by some audiophiles, simply because not all subs have a phase control. Bad reason! It's like the old joke about the drunk looking for his keys under the lamp post. "Where did you lose them?" "Over there -- but the light's better here."
Sorry to be a broken record. Trying to fix frequency response without optimizing phase is wasting your time.
I freely admit I don’t know much about phase. My subs do have a rotary knob rather than a 2 position switch for it so it’s adjustable.
As for the positioning, the subs are inside the mains, roughly 12” further back from the listener (at the front baffle). So should I be adjusting phase to try to compensate for that distance? Is there something I should be listening for or is it adjust, measure and repeat?
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Some people use Jennifer Warnes’ “Ballad of the Runaway Horse” to find the optimal positions for stereo speakers (https://www.audiocircle.com/index.php?topic=64321.0), the track may be useful for bass phase too. The procedure would take 2 people, one to sit in the sweet spot and one to twist the knob while listening to Rob Rasserman's taught deep bass line. The bass will be deepest when all the speakers are in phase.
You should use the CD or vinyl (excellent) for calibration but here is a taste:
https://www.youtube.com/watch?v=5BD7CFwiIsI (https://www.youtube.com/watch?v=5BD7CFwiIsI)
(https://images-na.ssl-images-amazon.com/images/I/51jxjaD9gJL.jpg)
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Some people use Jennifer Warnes’ “Ballad of the Runaway Horse” to find the optimal positions for stereo speakers (https://www.audiocircle.com/index.php?topic=64321.0), the track may be useful for bass phase too. The procedure would take 2 people, one to sit in the sweet spot and one to twist the knob while listening to Rob Rasserman's taught deep bass line. The bass will be deepest when all the speakers are in phase.
You should use the CD or vinyl (excellent) for calibration but here is a taste:
https://www.youtube.com/watch?v=5BD7CFwiIsI (https://www.youtube.com/watch?v=5BD7CFwiIsI)
(https://images-na.ssl-images-amazon.com/images/I/51jxjaD9gJL.jpg)
OK, so I am adjusting each sub against each other and the mains for the deepest sounding bass. I will play with that. WOuld it also be possible to play a repeating deep bass drum and tune the left sub to the left main, then disconnect those and do the right sub to the right main? Just spit balling here...
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Another way to check for phase is Reverse your L speaker wires,
i.e, make it out of phase. Now listen for less bass or the null.
do the same with the Right Speaker.
And if your subs are behind the plane of your L & R....then yes you
will have a Phase issue. How audible or Critical is your call.
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Another way to check for phase is Reverse your L speaker wires,
i.e, make it out of phase. Now listen for less bass or the null.
do the same with the Right Speaker.
And if your subs are behind the plane of your L & R....then yes you
will have a Phase issue. How audible or Critical is your call.
OK, I think I understAND. I will check these out when I get home this afternoon.
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I think any recording with well recorded bass with some space between the notes will work. Jazz bass player Ron Carter comes to mind.
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To summarize mine & others' posts, there are three main ways to adjust phase of the subs relative to mains. I've tried all three. All need to be done one channel (R or L + associated sub) at a time.
- Play music and adjust by ear. Fun, but not always accurate, in my experience, because it requires you to judge evenness across the whole bass range, by ear. (I hate to say that, because you can never listen to too much of Ron Carter's playing, IMO.)
- Reverse wires so a main is out of phase, then while playing a tone at the crossover frequency, adjust phase for the null (as heard at the main listening position). Less fun, but more accurate. Issues: You need to have a tone available at that specific frequency. And unless your sub has remote control, you need to be in two places at once (at the sub to adjust phase, in the listening chair to hear the null).
- Run a sweep, put a mic at the main listening spot, and adjust phase for maximum response at the crossover frequency. Fine-tune that by adjusting slightly for smoothest overall response. This possibly is the most accurate method, but is it really better than #2? Mainly in that it lets you see the peaks and dips of 10-20 dB that occur when things are out of phase. Also, you can watch the sweep (on a laptop) while you twist the phase knob, without running back and forth. I'd say it's the most objective method of the three.
Whatever you do, have fun! Welcome to the wonderful world of sub optimization.
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To summarize mine & others' posts, there are three main ways to adjust phase of the subs relative to mains. I've tried all three. All need to be done one channel (R or L + associated sub) at a time.
- Reverse wires so a main is out of phase, then while playing a tone at the crossover frequency, adjust phase for the null (as heard at the main listening position). Less fun, but more accurate. Issues: You need to have a tone available at that specific frequency. And unless your sub has remote control, you need to be in two places at once (at the sub to adjust phase, in the listening chair to hear the null).
So for my ignorance sake, tun off all speakers except the left, wire the left main out of phase, then turn on the left sub and do a test tone at (in this case) 36hz and dial the phase until they cancel correct?
- Run a sweep, put a mic at the main listening spot, and adjust phase for maximum response at the crossover frequency. Fine-tune that by adjusting slightly for smoothest overall response. This possibly is the most accurate method, but is it really better than #2? Mainly in that it lets you see the peaks and dips of 10-20 dB that occur when things are out of phase. Also, you can watch the sweep (on a laptop) while you twist the phase knob, without running back and forth. I'd say it's the most objective method of the three.
Also for my ignorance, watch the peaks at the crossover frequency (36hz) to get the highest peak at that frequency and then slight variations to make it smoother
[/list]Whatever you do, have fun! Welcome to the wonderful world of sub optimization.
I just want to be sure I completely understand.
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Yes, you've got it right. Since bass response will vary around the room, the listening and/or measuring should always be done at the main listening chair.
Then, of course, do the same thing independently for the R channel + R sub.
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I tried this before and the huge bump at 44 hz shook the room. Only recently I started peeling back to the 30’s.
If you're not using EQ, then you have to find your happy balance (compromise) between overall level and the size of the peaks. Measuring the mains by themselves is a must, so you know what the actual additive contribution of the subwoofers is. The HT approach is to find the subwoofer settings that provide the maximum in phase contribution to the system, and then EQ down the peaks. The "music" system approach is to just find the best compromise of overall level and minimizing objectionable peaks without EQ. In a dedicated room, bass trapping is pretty normal practice irrespective of HT or music purposes.
There is one other thing that I've never heard anyone mention - there's a chance that you don't have a good placement option for a second subwoofer. For example, I also have an open room, and I gave up running a second subwoofer in my system because the only spots I had available for the second sub resulted in destructive combing effects that I felt were clearly a net negative, no matter how I set the phase or crossover point. The system simply sounded better with 1 subwoofer.
Measure 1 sub at a time and measure the combined system results of each.
Here are basic measurements I'd like to know if it were my system:
- mains alone (or single main speaker if you prefer)
- sub 1 alone
- sub 2 alone
- mains with sub 1
- mains with sub 2
- mains with sub 1 and sub 2
And you get to play with the crossover settings on each sub as you start to combine them with your mains. This is just for 1 placement. Aren't we having fun? :thumb: Tuning bass with subwoofers is a real riot :thumb:
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Yes, you've got it right. Since bass response will vary around the room, the listening and/or measuring should always be done at the main listening chair.
Then, of course, do the same thing independently for the R channel + R sub.
:thumb:
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If you're not using EQ, then you have to find your happy balance (compromise) between overall level and the size of the peaks. Measuring the mains by themselves is a must, so you know what the actual additive contribution of the subwoofers is. The HT approach is to find the subwoofer settings that provide the maximum in phase contribution to the system, and then EQ down the peaks. The "music" system approach is to just find the best compromise of overall level and minimizing objectionable peaks without EQ. In a dedicated room, bass trapping is pretty normal practice irrespective of HT or music purposes.
There is one other thing that I've never heard anyone mention - there's a chance that you don't have a good placement option for a second subwoofer. For example, I also have an open room, and I gave up running a second subwoofer in my system because the only spots I had available for the second sub resulted in destructive combing effects that I felt were clearly a net negative, no matter how I set the phase or crossover point. The system simply sounded better with 1 subwoofer.
Measure 1 sub at a time and measure the combined system results of each.
Here are basic measurements I'd like to know if it were my system:
- mains alone (or single main speaker if you prefer)
- sub 1 alone
- sub 2 alone
- mains with sub 1
- mains with sub 2
- mains with sub 1 and sub 2
And you get to play with the crossover settings on each sub as you start to combine them with your mains. This is just for 1 placement. Aren't we having fun? :thumb: Tuning bass with subwoofers is a real riot :thumb:
Interesting you mentioned that as when Imoved the rear sub to the front right, the bass seemed good. When I moved the front left out of the corner and inside the right main there was more bass but it seems less sharp, softer attack. Which I thought was either crossing over too high or some phase issue.
I will try these that you mentioned. :thumb:
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The good news is that you have a measurement system, so not as much guesswork involved. My problems with the second sub were visible in the measurements - but you need baseline measurements so that you understand the impact of each individual subwoofer.
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Ok so 4 quick sweeps.
Left sub (0 phase crossed at 38hz @12db slope - forward facing)
(https://www.audiocircle.com/image.php?id=213687)
Right sub (0 phase crossed at 38hz @12db slope - right facing)
(https://www.audiocircle.com/image.php?id=213688)
Left main
(https://www.audiocircle.com/image.php?id=213692)
Right main
(https://www.audiocircle.com/image.php?id=213693)
4 back to back sweeps of each speaker as they are set up now.
EDIT: I just realized I had fabric stuffed in the port of the Heresys when I was trying to blend them. Damn.
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Looks like the main speaker balance knob got bumped. :icon_surprised:
I'll bet my old JBL L100 speakers have the same rock and roll 45 Hz hump and they sound great.
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Looks like the main speaker balance knob got bumped. :icon_surprised:
I'll bet my old JBL L100 speakers have the same rock and roll 45 Hz hump and they sound great.
Actually I don’t have a balance knob. I honestly can’t account
For the volume difference. Playing music music now and I can tell you there’s no 10db difference.
I have seen this on my sweeps so I wonder if the mic isn’t great or...
When running the left main (which has a side wall 3’ away I could detect pressure starting around 36 hz
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Maybe your speakers are very directional. If so, and the toe-in isn't symmetrical, it could show up as an issue in the measurements. AFAIK, you probably want to do a gated sweep if you really want to see the speakers performance without room effects for troubleshooting purposes. The subs actually look great except for the peak. Since those are sealed subs and I'm assuming no weird EQ shenanigans, that has to be a room mode, not a sub design issue.
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Don't your subs have a built in EQ? Most do, and they are useful for knocking down a peak like you are seeing. The peak at 45 hz is clearly a room mode since it shows up on all your graphs.
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Maybe your speakers are very directional. If so, and the toe-in isn't symmetrical, it could show up as an issue in the measurements. AFAIK, you probably want to do a gated sweep if you really want to see the speakers performance without room effects for troubleshooting purposes. The subs actually look great except for the peak. Since those are sealed subs and I'm assuming no weird EQ shenanigans, that has to be a room mode, not a sub design issue.
Very directional. Like tiny moves to the toe in are audible.
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Don't your subs have a built in EQ? Most do, and they are useful for knocking down a peak like you are seeing. The peak at 45 hz is clearly a room mode since it shows up on all your graphs.
Yes both subs have a parametric eq. My question is if I’m crossing over at 38 then doesn’t that nullify the 44hz bump? I could see it going either way.
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Yeah, very slightly different toe-in with respect to the measurement mic can cause the two speakers to look different, for sure.
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Yes both subs have a parametric eq. My question is if I’m crossing over at 38 then doesn’t that nullify the 44hz bump? I could see it going either way.
If you're using a 12 db/octave crossover, it's down by 12 db an octave higher, i.e., at 76 Hz. It would be down only a few dB by 44 Hz.
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Yeah, very slightly different toe-in with respect to the measurement mic can cause the two speakers to look different, for sure.
Makes sense. Ok so at this point should I go and align the left main to the left sub (phase)? Or is therefore work I should do first? Should I maybe move the subs forward first?
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If you're using a 12 db/octave crossover, it's down by 12 db an octave higher, i.e., at 76 Hz. It would be down only a few dB by 44 Hz.
Ahh, ok I will play with that.
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based on your measurements, i still think your mains are trailing off around 100hz. Just saying...
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based on your measurements, i still think your mains are trailing off around 100hz. Just saying...
I don’t disagree. Should I set the subs to 100 and see what damage I can do? :wink:
Edit: set to 100 and sure sound better to me. Can’t run sweeps until tomorrow but I will try it :thumb:
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Makes sense. Ok so at this point should I go and align the left main to the left sub (phase)? Or is therefore work I should do first? Should I maybe move the subs forward first?
I guess I'd do the phase alignment -- then you will know what the overall FR really looks like. That will allow you to play with the crossover and level of the sub to improve it if necessary. The crossover settings may affect the phase a little; the level should not.
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I guess I'd do the phase alignment -- then you will know what the overall FR really looks like. That will allow you to play with the crossover and level of the sub to improve it if necessary. The crossover settings may affect the phase a little; the level should not.
I'm hoping to do that this afternoon. :thumb:
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I may be wrong, but I think the phase adjustment depends on the crossover point. I'd pick crossover first and adjust phase to maximize the spl within the crossover region.
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I may be wrong, but I think the phase adjustment depends on the crossover point. I'd pick crossover first and adjust phase to maximize the spl within the crossover region.
Absolutely true. Unfortunately, it's also a chicken-and-egg thing. You can't see (or hear) how well a crossover frequency is performing until you get the phase right. So I'd suggest starting with a plausible xover point, optimizing the phase, and then making changes as needed.
In my system, changing the xover point a little (from 80 Hz to 65 Hz) made very little difference to the phase setting -- less than the 5-degree resolution my preamp uses to set it. There's no guarantee that's true for everyone, or for larger changes, but made me think that getting the phase right for the current of speaker positions is a good starting point. Then find a crossover frequency you like, then see if the optimal phase setting has changed.
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To summarize mine & others' posts, there are three main ways to adjust phase of the subs relative to mains. I've tried all three. All need to be done one channel (R or L + associated sub) at a time.
- Reverse wires so a main is out of phase, then while playing a tone at the crossover frequency, adjust phase for the null (as heard at the main listening position). Less fun, but more accurate. Issues: You need to have a tone available at that specific frequency. And unless your sub has remote control, you need to be in two places at once (at the sub to adjust phase, in the listening chair to hear the null).[/li
Just tried this. Basically listened to where the tone was lowest in volume as I moved the phase knob. Then I left it there. I have to say if I did it right then I’m
Kind of shocked how far off of 0 the phase is.
It never completely cancelled but the volume did dip half or more. Going to leave it here and listen for a while but wanted to confirm I did what was spec’d.
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You did it right -- as long as you were listening for the null at the main listening position -- not at the sub.
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You did it right -- as long as you were listening for the null at the main listening position -- not at the sub.
Damn. Hahaha ok I guess I have to do it again. :icon_lol:
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That's why it's easier to put a mic at the MLP, run the sweeps, and look at the response on a laptop, which you can have near the phase control. Easier, but not the only way. Maybe you have a helper who can turn the knob while you listen?
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That's why it's easier to put a mic at the MLP, run the sweeps, and look at the response on a laptop, which you can have near the phase control. Easier, but not the only way. Maybe you have a helper who can turn the knob while you listen?
I’ll see if my kiddo can help.
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The bottom graph looks better than the top. Keep in mind we're only really concerned from teh crossover frequency on down, usually around 80Hz or so. What it does above there is less critical.
If you have 2 subs, there are some strategies you can use to use cancellations in your favor to get a flatter response. Details in this article on my blog (http://www.gikacoustics.com/room-setup-speaker-placement-201-part-two-subwoofers/).
I've not read through this entire thread so my apologies if someone else has already addressed this.
I had twin 15" HSU Sealed Subs for quite a while in my 2-channel music system. I eventually realized that a lot of my room peaks and nulls were caused by the subs exciting the walls and or floor causing all kinds of havoc in the lower frequencies. Once the walls and or floors start vibrating they produce their own low frequency pressure waves.
I found that Auralex SubDude isolation platforms effectively isolate forward firing Subs from the floor. In my case the subs were exciting the floor (vibrating) and those vibrations extended out to and up the walls. The isolation platforms eliminated that problem and I started to get much flatter low frequency room response.
https://www.sweetwater.com/store/detail/SubDudeHT--auralex-subdude-ht-subwoofer-isolation-pad (https://www.sweetwater.com/store/detail/SubDudeHT--auralex-subdude-ht-subwoofer-isolation-pad)
I also found that downward firing subs are worse yet (get them on isolation platforms). Even once you get them on isolation platforms you have to be careful about how close you place them to walls. Since they fire down & out, then can cause an adjacent wall to begin vibrating and that will travel to the floor and other walls. In my case if I had them 12 or more inches from the wall they would not excite the wall.
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Someone earlier said that corner placement will maximize bass output of a sub. That is true. Even the manufacturer of my SVS sub recommends corner placement.
However, my experience, with 2 different subs in 2 different rooms, corner placement excited room modes and it wasn't pretty. In both cases I got a massive hump around 40-45 Hz that couldn't be tamed. I've had better luck placing my single subwoofer midway along a side wall. But like everyone is saying - experiment. YMMV.