AudioCircle
Industry Circles => GIK Acoustics => Topic started by: David60 on 2 Jul 2021, 07:01 pm
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Hello all,
Trying to understand how to treat my very unfriendly room. It's 4mx8mx2.5 with standmount speakers firing from the short wall, lengthwise. Placement is 45cm from rear of speaker to front wall. 1m on either side of speaker. This is max allowable positioning for relative domestic peace. Listening position is just less than 3m from speakers. This setup produces:
> Peaks between 40 and 50hz and between 60 and 70hz and a nasty dip around 140hz for more than 20dB of difference...as measured with REW from listening position. The bass frequencies on most music are reliably unlistenable beyond a volume level of approximately 55/60 dB.
> If I measure test tones of 40, 50 and 60hz with a dB meter, I get a +25-30dB build-up in the front L/R corners, as compared to the listening position.
Obviously this isn't working.
First reaction is to try floor to ceiling tri-traps in L/R corners. No room for Soffits. Question is what can I try as additional treatment, which product and what position given room layout and constraints?
Not an easy task I'm finding...Thanks for your comments and suggestions. Brgds.
(https://www.audiocircle.com/image.php?id=226397)
(https://www.audiocircle.com/image.php?id=226398)
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Are the speakers Focal Sopra and if so did you try the port plugs to reduce some of the bass output? Try plugging one side at a time to see if that helps. That being said, a few other things I would do is get a small low equipment rack to go between the speakers, move the tv to the top of that, then get corner bass traps to go in the corners on the front wall behind the speakers. I know that the tv will block the lower part of the window and the equipment rack may partially block the radiator under the window which may be of some concern. Moving the speakers out a bit more from the front wall may also help (do it an inch at a time over a period of time so your significant other won’t notice).
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Hello,
Thanks for your comments. Yes, the Sopras come with foam bungs which were tested and validated by Focal engineering but they remove too much bass. This leaves me with 3 choices:
1. Listen to music with foam bungs and have no bass.
2. Listen to music without foam bungs and enjoy 80% bass on all music.
3. Sell off everything at a massive loss and take up macramé as a new hobby.
I refuse to EQ/DSP so option 3 appears to be the most reasonable.
I did reach out to GIK according to their "design proposition" tool and I received a response.
Frankly, their response has totally dissuaded me from ever becoming a customer.
Brgds.
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Is that the Selah Voce, with the SB acoustics dome mid? I'm a former owner of the Selah Verita and have always been intrigued with
Rick's designs. His 2 best 3-ways are now the Tempesta MKII, and the Voce I believe; how do you like it? Virtually no one except ATC uses
a Dome midrange anymore, I'd like to hear your opinion-
pawsman
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pawsman,
Those look like Bryston Mini T’s.
Anyway…
David60,
Since you are versed in using REW (which is 1/2 the battle), I would suggest you make a series of measurements where you move the listening position (ie microphone), in 6-12 inch increments to see how dramatically you can alter that null between 100-200 Hz. This has to do with SBIR (Speaker Boundary reflections not just “room nodes.”) Alternatively you can move the speakers and preferably, you should do both. It's a journey and an education, all at once!
Set your measurements so that you are ONLY measuring between 20Hz to 400Hz and add 1/12th or 1/6th octave smoothing. We need to see more detail. If you want to get critical, just measure one speaker at a time.
What kind of construction is this room? Concrete? Tiled floors. You will definitely have reflections as such and it would be best to add some room treatments (corners, etc…), but it sounds like you have some social protocols that you must adhere to. 8)
All rooms have these issues for the most part, but they can be exaggerated by certain dimensions and certain construction materials.
Don’t under estimate the profound difference that altering the listening position and/or speaker position or both can make!
More on SBIR & listening positions:
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/
Best,
Anand.
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Deleted
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pawsman,
Those look like Bryston Mini T’s.
Anyway…
David60,
Since you are versed in using REW (which is 1/2 the battle), I would suggest you make a series of measurements where you move the listening position (ie microphone), in 6-12 inch increments to see how dramatically you can alter that null between 100-200 Hz. This has to do with SBIR (Speaker Boundary reflections not just “room nodes.”) Alternatively you can move the speakers and preferably, you should do both. It's a journey and an education, all at once!
Set your measurements so that you are ONLY measuring between 20Hz to 400Hz and add 1/12th or 1/6th octave smoothing. We need to see more detail. If you want to get critical, just measure one speaker at a time.
What kind of construction is this room? Concrete? Tiled floors. You will definitely have reflections as such and it would be best to add some room treatments (corners, etc…), but it sounds like you have some social protocols that you must adhere to. 8)
All rooms have these issues for the most part, but they can be exaggerated by certain dimensions and certain construction materials.
Don’t under estimate the profound difference that altering the listening position and/or speaker position or both can make!
More on SBIR & listening positions:
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/
Best,
Anand.
Love when Anand jumps in with this :)
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It's for exactly these reasons that I've pretty much abandoned box speakers and use open baffle speakers instead.
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It's for exactly these reasons that I've pretty much abandoned box speakers and use open baffle speakers instead.
Does that comment really help David60 with a viable solution?
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Hello,
Thanks for your comments. Yes, the Sopras come with foam bungs which were tested and validated by Focal engineering but they remove too much bass. This leaves me with 3 choices:
1. Listen to music with foam bungs and have no bass.
2. Listen to music without foam bungs and enjoy 80% bass on all music.
3. Sell off everything at a massive loss and take up macramé as a new hobby.
I refuse to EQ/DSP so option 3 appears to be the most reasonable.
I did reach out to GIK according to their "design proposition" tool and I received a response.
Frankly, their response has totally dissuaded me from ever becoming a customer.
Brgds.
David,
If you refuse EQ/DSP, then I am going to assume that implementation of one or more subwoofers and/or treatments is also a no go. And whether they are OB or monopole mains or OB or monopole subs becomes a non starter since you need the room as well as time to experiment/measure, etc...
I have seen good examples of both OB and monopole mains speakers and subs as well as a mix of the two.
SBIR exists for OB speakers as well...it's just less apparent due to less ringing in the room which is particularly apparent in the decay/waterfall graphs.
Last weekend, I participated in the implementation of 2 monopole Rythmik sealed subwoofers to a pair of sealed mains speakers. It took the careful participation of all 3 of us, and we were able to move the subs, move treatments, move the mic and run REW for several runs before finding a good medium that measured well and sounded great to the owner. That might be an option for you.
Anyway, if it doesn't work out, perhaps consider headphones?
Best,
Anand.
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Does that comment really help David60 with a viable solution?
I’m merely pointing out an option that people might not consider otherwise. As for myself, I had box speakers for a long time and their interaction with my room was always problematic. Even with treatments and fairly sophisticated EQ. When I moved to full OB speakers those problems were solved almost immediately.
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You should be able to make this work. Try 62% back from the front wall for a seating position so you are not in a null in the center of the room. The advice given is sound. Take measurements every 6 inches and you may find a nice compromise location. I moved my seat farther back to avoid some build-ups than the math said I should but the REW told me differently and it worked. Keep experimenting. I used tape on the floor and the walls and a camera tripod to incrementally move the mic for each measurement.
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Go the diy trial and error route with plugging the ports. Most guys have microfiber towels in the garage. Grab two, partly block (~50%) each port with one in each hole and measure again. I've done this with pretty decent success taming that same style big 45hz mode. Also, like others have suggested, try pulling your speakers out another 6" ND see if that helps as well. Try that before you pull your hair out in frustration or take up macrame.
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SBIR exists for OB speakers as well...it's just less apparent due to less ringing in the room which is particularly apparent in the decay/waterfall graphs.
Best,
Anand.
Yes, this fact (less ringing in the room due to the nature of OB sound propagation) is a major reason that OB speakers work better in almost any room you can name, but are especially helpful in problematic rooms like this one (and like my rooms, too).
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Don’t give up just yet! It can be a long process and also a great learning experience. Regardless of what recommendations GIK made, I would still experiment with bass traps, starting in the corners behind your speakers where you said there is a lot of bass gain. Next was experimenting with positioning. It is a game of inches. The article below has lots of great information and was posted in another circle. Read the whole article, not just the section on bass traps.
https://ethanwiner.com/acoustics.html#bass%20traps
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David,
I can understand why you might be frustrated, but honestly, if you were looking at this picture as an impartial bystander wouldn't it cause you concern?
There is an untreated window on the front wall. There is a TV in a front corner. Hard floors with a rug essentially doing nothing acoustically beneficial. The speakers are way too close to the front wall. The cabinet to the right is not helping either.
Now I understand if you have constraints from a loved one regarding the room décor, but didn't you know that before spending over $7000 on a top quality speaker? This is like buying a 911T and configuring it to never use above 3rd gear.
I would read over Annand's assessment again. Headphones are going to give you more musical enjoyment than that rig in that untreated room can.
Please forgive me if it seems like I am comin up on ya but I guess in a way I am jealous. I am not including you in this because you are trying your best in a difficult situation and even using measurements to help you, but I am sure you have seen those pictures of mega-buck systems set up without a thought to getting the best out of them. Don't their dealers help these people? Just frustrates me a bit.
Might there be another room in the house that could work for you? Have you tried setting up along the long wall?
Anyway I hope you find a solution that allows those Focals to sing!
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Are you familiar with the subwoofer Swarm? In your case you'd plug the ports as mentioned and use 3 or 4 very small subwoofers placed around the room to even out the low frequencies. It's a very effective technique.
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David,
I can understand why you might be frustrated, but honestly, if you were looking at this picture as an impartial bystander wouldn't it cause you concern?
There is an untreated window on the front wall. There is a TV in a front corner. Hard floors with a rug essentially doing nothing acoustically beneficial. The speakers are way too close to the front wall. The cabinet to the right is not helping either.
Now I understand if you have constraints from a loved one regarding the room décor, but didn't you know that before spending over $7000 on a top quality speaker? This is like buying a 911T and configuring it to never use above 3rd gear.
I would read over Annand's assessment again. Headphones are going to give you more musical enjoyment than that rig in that untreated room can.
Please forgive me if it seems like I am comin up on ya but I guess in a way I am jealous. I am not including you in this because you are trying your best in a difficult situation and even using measurements to help you, but I am sure you have seen those pictures of mega-buck systems set up without a thought to getting the best out of them. Don't their dealers help these people? Just frustrates me a bit.
Might there be another room in the house that could work for you? Have you tried setting up along the long wall?
Anyway I hope you find a solution that allows those Focals to sing!
Hello,
Agree that the room layout is beyond worrisome but it isn't going to be modified during this century, except for a few centimeters here and there. To be clear, I did not pay the "stoopid" retail price for these speakers and I still have my previous PMCs they're replacing. Plus, in order to sell these things Focal dealers generally discount up to 30% at dealers, so that silly MSRP is pure science fiction. I was able to make trade deal with a private individual that I couldn't refuse...so I went for it notably because I like the look of these speakers and I know they can work, either by room treatment, or by EQ/DSP or by using the foam plugs. In fact, I'm listening now without plugs and frankly it sounds like a damned good speaker. I am not and never will be a headphones guy. How do you play with and constantly tweak a pair of headphones? Plus, my wife and grown kids, buddies, friends and neighbors all appreciate music...
Half the problem is with me...self-declared "golden ears" and extremely critical listener. I hear everything and know precisely what I am hearing, whether from a music reproduction system or out in the street, at work, etc. It's a real curse. So, I'm probably pushing too hard on the envelope of diminishing returns with exaggerated expectations. Nobody said extreme music lovers and audiophiles were a perfectly sane set of mortals. No offense intended to anyone of course, I know that I suffer from a form of neurosis humorously referred to as audiophilia nervosa.
That said, improvements can be made to this room as it is and I'm just about to pull the trigger. Will certainly update when it happens. Thanks for your comments. Brgds.
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Go the diy trial and error route with plugging the ports. Most guys have microfiber towels in the garage. Grab two, partly block (~50%) each port with one in each hole and measure again. I've done this with pretty decent success taming that same style big 45hz mode. Also, like others have suggested, try pulling your speakers out another 6" ND see if that helps as well. Try that before you pull your hair out in frustration or take up macrame.
Hello, the Sopra 1 is the only Sopra model supplied with factory validated foam plugs. As much as I intellectually dislike aperiodic modification of a BR loudspeaker I must admit that their foam bungs are indeed efficient, impacting the FR curve up to about 200hz. Beyond that point, the measured curve is practically identical to the unplugged speakers. Frankly, this is very impressive result. My personal opinion is that it drops down a bit too much for my taste and lacks punch and relative depth. Yes, I am nitpicking big-time.
My current idea is perhaps to add some room treatment in hopes of better balancing the unplugged option.
Brgds.
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Are you familiar with the subwoofer Swarm? In your case you'd plug the ports as mentioned and use 3 or 4 very small subwoofers placed around the room to even out the low frequencies. It's a very effective technique.
Thanks but I definitely won't be adding more equipment like that. I've had enough 2.0 systems working fine here and I dislike relying on subwoofers for a 2 channel system. I mentioned earlier that I am a bonafide psycho and you may choose to agree. Brgds.
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You should be able to make this work. Try 62% back from the front wall for a seating position so you are not in a null in the center of the room. The advice given is sound. Take measurements every 6 inches and you may find a nice compromise location. I moved my seat farther back to avoid some build-ups than the math said I should but the REW told me differently and it worked. Keep experimenting. I used tape on the floor and the walls and a camera tripod to incrementally move the mic for each measurement.
Yes, will continue to brainstorm and tweak. I'm currently sitting at 53% of room length. A bit less and a bit more and the "bass tsunami" is much less evident. However, not being single has both advantages and disadvantages...although after 31 years of marriage the "advantage column" is not as convincing as it once was. Therefore I have to tweak secretly in the middle of the night disguised as a burglar. This hobby has all kinds of surprises over a lifetime. Brgds.
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I'll chip in with things others have not mentioned.
Possibly your significant other is not as dogmatic as you think. I speak from experience. I was allowed to place my Spatial X3s in a favorable location ---this involved significant furniture shifting which she helped with---and 4 feet away from the front wall. I promised to slide the speakers closer to the wall (by putting teflon furniture sliders under the feet) whenever we have guests over, which doesn't happen more than once a fortnight.
At the end she realized that she slightly prefered the new configuration of the room, with a some open space and some diagonals introduced.
I am in audio heaven and she agrees too that the sound now is awesome.
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Don’t give up just yet! I’ve moved my speakers many times over the 51/2 years I’ve owned them trying to optimize their sound in my problematic room. It can be a long process and also a great learning experience. Regardless of what recommendations GIK made, I would still experiment with bass traps, starting in the corners behind your speakers where you said there is a lot of bass gain. They provided the largest single improvement in smoothing out the bass response in my situation. Next was experimenting with positioning. Regarding the port plugs, I initially had the same experience as you; ports plugged on both speakers killed the bass but plugging only one speaker’s port eliminated much of the bass boom while still providing plenty of bass. I finally found the best spot in my room where the bass response is smooth, deep and tight and no port plug is used. It is a game of inches. The article below has lots of great information and was posted in another circle. Read the whole article, not just the section on bass traps.
https://ethanwiner.com/acoustics.html#bass%20traps
Yes, thanks again for the encouragement. Radio Paradise streaming now through the Naim equipment on the unplugged Sopras is a good listen at modest volume. Will keep trying indeed as I want to tri-trap the 2 front L/R corners and find a way to adjust the TV and equipment rack positions.
Below we see the plugged/unplugged effect as measured from my listening position:
(https://www.audiocircle.com/image.php?id=226502)
Red is unplugged and Green is both speakers plugged. One speaker plugged (not shown) is somewhere in between but I'm worried about the imbalanced impedance load that this would present to the amplifier...and it just seems a bit strange to plug just one speaker. I haven't given up yet. Brgds.
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Well if you are going to stick with box speakers, I'll give you some tips from when I was doing box speakers and EQ. First, if you can do bass traps, then those are the most effective in dealing with bass humps as well as dealing with the bass causing the room to ring.
Don't dismiss a swarm set of subs just yet, if you DIY them then you can make them to match your decor.
For now, the best thing to do is measure each speaker individually using RCA shorting plugs like these:
https://www.amazon.com/Shielded-Shorting-Filter-Noise-Canceling/dp/B01N0LNTTX/ref=sr_1_5?dchild=1&keywords=rca+shorting+plugs&qid=1625505255&sr=8-5
Plug one in to one side of your amp and keep your regular RCA cable plugged in to the other side. Only one speaker will produce noise now. Measure, then switch the shorting plug to the other channel and measure the 2nd channel.
Compare the 2 measurements. You will notice that some peaks are the same from speaker to speaker but others peaks are different. The ones that are the same, you can use the EQ for both speakers at a time. For the humps that are unique to a particular speaker, EQ only that speaker to deal with them.
Other tips for EQ. Start with the humps that are lowest in the bass and work upwards. Because some of your higher level humps (and nulls) might be result of the things happening lower down. Also, only use 'cuts' in your EQ, never ever use 'boosts'. It's much better to drop bass humps and leave the bass nulls alone.
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Well if you are going to stick with box speakers, I'll give you some tips from when I was doing box speakers and EQ. First, if you can do bass traps, then those are the most effective in dealing with bass humps as well as dealing with the bass causing the room to ring.
Don't dismiss a swarm set of subs just yet, if you DIY them then you can make them to match your decor.
For now, the best thing to do is measure each speaker individually using RCA shorting plugs like these:
https://www.amazon.com/Shielded-Shorting-Filter-Noise-Canceling/dp/B01N0LNTTX/ref=sr_1_5?dchild=1&keywords=rca+shorting+plugs&qid=1625505255&sr=8-5
Plug one in to one side of your amp and keep your regular RCA cable plugged in to the other side. Only one speaker will produce noise now. Measure, then switch the shorting plug to the other channel and measure the 2nd channel.
Compare the 2 measurements. You will notice that some peaks are the same from speaker to speaker but others peaks are different. The ones that are the same, you can use the EQ for both speakers at a time. For the humps that are unique to a particular speaker, EQ only that speaker to deal with them.
Other tips for EQ. Start with the humps that are lowest in the bass and work upwards. Because some of your higher level humps (and nulls) might be result of the things happening lower down. Also, only use 'cuts' in your EQ, never ever use 'boosts'. It's much better to drop bass humps and leave the bass nulls alone.
Thanks for the tips. For the moment, yes, box speakers as I had a wonderful time with Magnepan and Martin Logan when I was younger, now I'm less inclined to fight with the refrigerator sized transducers. Best luck I ever has was/is with Sonus Faber, of which I still have two pairs at home, the oldest being 23 years old...
Very interested in the OB implementations but these days my room is the limiting factor. Yes, agreed, I wouldn't attempt to boost a null in EQ. Thanks again. Brgds.