Help with HUGE 36Hz bass peak.

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TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #20 on: 17 Jan 2011, 01:48 pm »
Show us the REW measurements again to see if this plugin works, we'll let you know! Best of luck!  :wink:

Anand :thumb:

How would I go about getting a REW measurement while using the plugin?  I've been working with REW for years, but I use its internal sweeps.  How would I do it through Squeezebox Server?  If I can do it, I'd be happy to show the results.

poseidonsvoice

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Re: Help with HUGE 36Hz bass peak.
« Reply #21 on: 17 Jan 2011, 01:56 pm »
How would I go about getting a REW measurement while using the plugin?  I've been working with REW for years, but I use its internal sweeps.  How would I do it through Squeezebox Server?  If I can do it, I'd be happy to show the results.

Ahhh! Great point! It would just be nice to verify what you are hearing is actually reality from a measurement standpoint.  :duh:

Well...let us know what you think of it from a subjective standpoint. It might be a good temporary fix for you and it's free to boot.

Anand.

gitarretyp

Re: Help with HUGE 36Hz bass peak.
« Reply #22 on: 17 Jan 2011, 03:19 pm »
How would I go about getting a REW measurement while using the plugin?  I've been working with REW for years, but I use its internal sweeps.  How would I do it through Squeezebox Server?  If I can do it, I'd be happy to show the results.

You can use SynRTA for that. With that program, you can output the test signal as a file and play it back on the Squeezebox. It doesn't measure low frequencies as accurately as REW, but for the purpose of comparison, it should be adequate.

shadowlight

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Re: Help with HUGE 36Hz bass peak.
« Reply #23 on: 17 Jan 2011, 03:23 pm »
TJ,
Found the following on the Inguz website which seems to imply that it does do mp3 equalization - http://inguzaudio.com/installation/debian/.  If I am reading it correctly you should be able to use RealTraps Test CD to run a sweep through the Sqeezebox and Inguz Equalization.
"Configuring File TypesAfter installing the plugin and the filter processor, you need to configure SlimServer to use them for particular types of audio files. You can choose to only process certain files (FLAC, or MP3, for example), but you’ll usually want to set this configuration to process every type of audio.
To playback MP3 files with InguzDSP, you will need to install LAME.  Follow the LAME instructions on the Slim Wiki.
From the SlimServer web interface, select Server Settings -> File Types
. Check all the boxes which have “InguzDSP” in the decoder listing, and uncheck everything else.
Finally, restart SlimServer again."

tonyptony

Re: Help with HUGE 36Hz bass peak.
« Reply #24 on: 17 Jan 2011, 03:37 pm »
I've tried MP3s in the past with Inguz and recall having some issues, but that was a while ago and I didn't try very hard since all of my "real" ripped music is FLAC.

TJ, I think the demo version of TrueRTA will let you at least do a screen shot of the measured room response.

BTW, I have verified in my own system using TrueRTA that Inguz does indeed work.

tg3

Re: Help with HUGE 36Hz bass peak.
« Reply #25 on: 17 Jan 2011, 11:01 pm »
Another option is change your mains to dipoles, which (it is claimed) do not excite the room resonances as much.

I also have a large room resonance, centered at 50 Hz. I let the Oppo 990 handle the crossover duties to the sub, and then EQ with an SMS-1. Its not perfect, but at least I can listen without wincing. I plan to move to dipole mains, probably the GR Research V1 or V2s.

TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #26 on: 17 Jan 2011, 11:15 pm »
Thanks for all the responses guys.  It helps a lot.

I pulled out my REW setup today to use it strictly as a db meter with the calibration files.  Here is what I ended up with for readings using Inguz EQ:
(Note: I only adjusted the 50, 40, 32, and 25Hz EQ points)

80Hz = 74.7db
63Hz = 76.2db
50Hz = 77.2db
40Hz = 76.4db
36Hz = 81.1db (not an EQ point, but this is the center of my bass peak)
32Hz = 75.4db
25Hz = 75.7db
20Hz = 75.7db

At this point, I can say I am fairly happy with the results.  The bass sound great now with nice definition and there's plenty of it (even in my large room).  I was not convinced the digital EQ was transparent when I first listened.  I did find that when the DSP was active, the overall gain was too high.  I lowered it and now I'm not sure I can tell a difference other than the bass response.  I will need more listening time to make a final decision, but so far so good.  It is fantastic to hear just my mains running full range.  This is possibly the best sound I've had to date.

I'm still thinking I'm going to try to build a couple of Helmholtz resonators tuned to 36Hz with a narrow Q.  At least I have a lot less pressure on me to get going.  This gives me more time to figure out the model, build materials, and overall look. 

Thanks for everyone's comments thus far.  I still have a lot to figure out with Inguz EQ, but it's working well for the moment. 

 

TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #27 on: 19 Jan 2011, 01:54 am »
Just to update things...

I can without a doubt hear negative things running the Inguz EQ plugin.  I tried everything to convince myself that I was crazy, but I can hear it.  I'm planning to do a blind test one of these days, but after listening tonight, I can say that I'll pass 100%. 

When the Inguz EQ is engaged, I lose a bit of smoothness to the sound.  It becomes slightly digital or grainy sounding.  I also lose a bit of imagining and the speakers become more obvious.  Subtle details are still there, but there are not as obvious.  Basically the sound takes on a sort of fake quality.  This is not going to be a solution for me; at least at this point.  I really wanted this to work, so this sucks.

So back to my original question.  Again, I do not want to use subs at all.  My mains dig deep and play loud.  They are way more than I need for 2-channel music.  Besides, I can't seem to find a way to high-pass my mains without adversely affecting the sound.  So that's just another reason for me to pass on the subwoofer ideas. 

If the only solution may be the Helmoltz resonator idea, I'm going to start modeling something for testing.  Any other room treatment ideas?


tonyptony

Re: Help with HUGE 36Hz bass peak.
« Reply #28 on: 19 Jan 2011, 03:11 am »
When the Inguz EQ is engaged, I lose a bit of smoothness to the sound.  It becomes slightly digital or grainy sounding.  I also lose a bit of imagining and the speakers become more obvious.  Subtle details are still there, but there are not as obvious.  Basically the sound takes on a sort of fake quality.

TJ, this has come up in older posts. I don't recall if it was in the SB forums or the now defunct Inguz forums. I seem to remember that in some cases it was due to slight clipping, which can be adjusted (manually) in one of the Inguz configuration files. I'm not sure if it was ever explained outside of that context, however, so beyond that I can't help. One thing, though, is that if you are using it with any aggresive boost to any of the equalization points - which I suspect you are not since you're trying to reduce a peak - it does increase the possibility of clipping.

IMO, Inguz works better when using its DSP functions to correct both amplitude and phase anomalies.

TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #29 on: 19 Jan 2011, 03:38 am »
TJ, this has come up in older posts. I don't recall if it was in the SB forums or the now defunct Inguz forums. I seem to remember that in some cases it was due to slight clipping, which can be adjusted (manually) in one of the Inguz configuration files. I'm not sure if it was ever explained outside of that context, however, so beyond that I can't help. One thing, though, is that if you are using it with any aggresive boost to any of the equalization points - which I suspect you are not since you're trying to reduce a peak - it does increase the possibility of clipping.

IMO, Inguz works better when using its DSP functions to correct both amplitude and phase anomalies.

I searched and searched, but I have only found positive comments on Inguz.  I wish the Inguz forums weren't gone as I've seen many references to it in other posts. 

I had to lower the overall gain a bit to "match" the level without the plugin engaged.  I also checked the log.txt file and didn't find any clipping.  I didn't expect to see anything as you are correct about only cutting the lowest frequencies. 

I was attempting to keep things simple and only use the graphic EQ.  I guess I'll look into the DSP function and see if that works better. 

Thanks.

tonyptony

Re: Help with HUGE 36Hz bass peak.
« Reply #30 on: 19 Jan 2011, 12:42 pm »
I searched and searched, but I have only found positive comments on Inguz.  I wish the Inguz forums weren't gone as I've seen many references to it in other posts.

You and me both. While information about Inguz is available on the SB forums, the old Inguz message board had a lot of useful fundamental information on it. I wish Hugh (creator of the plugin) had kept the board up even if it was no longer open for use.

I was attempting to keep things simple and only use the graphic EQ.  I guess I'll look into the DSP function and see if that works better. 

I'd give it a try, but with a caution - it works best if you have a decent calibrated mic. I have a Behringer ECM8000 which I sent out to be calibrated. It can be done with an uncalibrated mic like the ECM but the correction in the upper frequencies may not be optimal.

jimdgoulding

Re: Help with HUGE 36Hz bass peak.
« Reply #31 on: 29 Jan 2011, 09:12 pm »
Haven't read all the above so dunno if this has been mentioned, but rather than listen from your sofa get an occasional chair that is comfortable, of course, and put it in front of your sofa and see/hear what happens.  Reflection off your back wall will change for starters.  Try it if you're serious.  Cheers.

Oh, and move your coffee table out of the field.

Barry_NJ

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Re: Help with HUGE 36Hz bass peak.
« Reply #32 on: 29 Jan 2011, 09:43 pm »
Here's a thought that hadn't been suggested, active noise canceling...

Build a cross-over that only passes frequencies in the mid 30s. Run the same signal feeding your main to this cross-over and from your crossover to your sub but invert the phase. Then you can adjust the volume of the sub to cancel out the peak.

Thoughts?

TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #33 on: 30 Jan 2011, 04:55 pm »
Haven't read all the above so dunno if this has been mentioned, but rather than listen from your sofa get an occasional chair that is comfortable, of course, and put it in front of your sofa and see/hear what happens.  Reflection off your back wall will change for starters.  Try it if you're serious.  Cheers.

Oh, and move your coffee table out of the field.

Your idea of the chair would work if I didn't have that stupid chase lounge part of my couch.  I really regret that purchase and the couch is a piece of junk anyway.  I'm looking to replace it sometime later this year when I can afford to get what I want. 


TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #34 on: 30 Jan 2011, 05:04 pm »
Here's a thought that hadn't been suggested, active noise canceling...

Build a cross-over that only passes frequencies in the mid 30s. Run the same signal feeding your main to this cross-over and from your crossover to your sub but invert the phase. Then you can adjust the volume of the sub to cancel out the peak.

Thoughts?

When I first read your post, I thought the idea was ridiculous.  But the more I thought about it, I figured it would be worth a try.  So I pulled out my measuring setup and tried using my SMS-1 to EQ my sub to function as an "active noise cancelling" device. 

After about a hour of screwing around, I really got nowhere.  No matter what I did, the sub was interfering with too many other frequencies when I got the bass peak to be cancelled.  Basically I couldn't seem to control the situation and I gave up. 

Disappointed, I decided to spend some time re-EQ'ing my sub and integrating it for music again.  I got a very nice measured room response with my main running with the sub.  I must have done a little better job of EQ'ing this time as the bass sounds better overall. 

I'm thinking I may just scrap this whole idea and focus on a better high-pass filter for my mains so I can keep the sub for music.  I'm going to contact Marchand this week and see what they have to say.   

jimdgoulding

Re: Help with HUGE 36Hz bass peak.
« Reply #35 on: 30 Jan 2011, 06:37 pm »
Your idea of the chair would work if I didn't have that stupid chase lounge part of my couch.  I really regret that purchase and the couch is a piece of junk anyway.  I'm looking to replace it sometime later this year when I can afford to get what I want.
I think you should try it anyway.  If you have to move your chase a bit down the wall to accomodate a chair or move your speakers more closely together to maintain a triangle with your chair/ears or both, think you'll find it interesting.  Don't think you want your seat or microphone up against a wall anymore that your speakers.  Best wishes.

Jack Caldwell

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Re: Help with HUGE 36Hz bass peak.
« Reply #36 on: 1 Mar 2011, 04:44 pm »
If you are running with mostly digital as a source, you could try a Behringer DEQ2496 running digital only for in/out. It is quite transparent when used this way and it has tremendous flexibility, along with 10 bands parametric + 31 bands 1/3 octave.
And you can store different settings in memory so you can compare between different eq correction curves.

It also functions as a 63 band analyzer with an extremely handy pink-noise generator built in. Parts express sells a $49 calibrated mic that works really well with this. Find it at http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-801

Like I said, the DEQ2496 is extremely transparent running in digital I/O. Some have said otherwise, but when questioned, it invariably turns out they are using the analog i/o instead of the digital.
(Warning: The analog sections on the DEQ2496 is not the best unless modded, use only digital I/O)

Run it between digital source and DAC. It can be had for $275 to 300 new on Ebay, and if you try it and don't like it, you can re-sell it rather easily for $240-275. I buy several a year to integrate with my H1 speaker systems (you can see it at holisticaudio.com), so if you don't like it I may be interested as well. 

Try it, it is an outstanding solution for not much money.

roscoeiii

Re: Help with HUGE 36Hz bass peak.
« Reply #37 on: 1 Mar 2011, 04:48 pm »
Jack,

What are your thoughts about the Behringer vs. software-based EQ manipulation? I believe Pure Music has a decent EQ, and the recently released Fidelia may have the option as well. What are the advantages and disadvantages to each approach?

Jack Caldwell

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DSP on Mac, Pure Music, etc.
« Reply #38 on: 1 Mar 2011, 09:02 pm »
Hey Roscoe, you can do pretty much the same thing using the Mac, but you don't have the flexibility of storing different presets as you do on the Behringer... requires tons of work-arounds.

That being said, my current favorite application for getting at the CoreAU functions on the Mac is AudioHijackPro (AHP)... among other things it's only $32, makes it easy to try. I run it and test on the Mac also using Fuzzmeasure 3, this allows me to change filters and see the response very quickly. The combination is extremely powerful, and very accurate, as Fuzzmeasure allows importation of mic cal files.

The Core AU functions (inherently found in the Mac, BTW) include lots of parametric bands and graphic eq, same as Pure Music, but with the SIGNIFICANT advantage that you can divert the audio stream, do the eq, and then feed the EQ'd output into your choice of Itunes, Pure Music, Amarra and many others. I have tested it on the three mentioned, and it works great.

BTW, using AHP has allowed me to measure the different filter characteristics because it does the processing in real-time. This has also let me compare extensively between Amarra and PM. At this time my favorite is Amarra.

However, as an example, fixing the 36Hz peak as discussed in this thread may not be all that simple. Here's why:
1)At the listening position there is this huge peak, many would simply just EQ for that, but that can drastically change the acoustic power response, and usually not for the better.
2) It is often advisable to measure at many different places in the room and then determine an "average" response and EQ for that.
3) In other cases, the EQ could be more heavily weighted to include more of the seating location but also some of the room response. 

The final arbiter is to be able to verify by ear which of these options is the most satisfying. But to do so requires the ability to change from one EQ setting to the other on the fly, and that's where the Behringer really shines.

When I do custom installs for my speakers (HolisticAudio.com), and the client is only going to use the Mac, I first tune with the Behringer, find the "optimum" from the 3 part menu above, and then re-create that on the Mac using AHP. The filters do not have the exact same Q, but I've developed a methodology that gets it to perform identically, and it sounds equally good whether from the Mac or the Behringer.

One other advantage of using the Behringer is that using many filters in the MAC can create delay in the audio, whereas the Behringer has no audible latency.

TJHUB

Re: Help with HUGE 36Hz bass peak.
« Reply #39 on: 2 Mar 2011, 12:20 am »
If you are running with mostly digital as a source, you could try a Behringer DEQ2496 running digital only for in/out. It is quite transparent when used this way and it has tremendous flexibility, along with 10 bands parametric + 31 bands 1/3 octave.
And you can store different settings in memory so you can compare between different eq correction curves.

It also functions as a 63 band analyzer with an extremely handy pink-noise generator built in. Parts express sells a $49 calibrated mic that works really well with this. Find it at http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-801

Like I said, the DEQ2496 is extremely transparent running in digital I/O. Some have said otherwise, but when questioned, it invariably turns out they are using the analog i/o instead of the digital.
(Warning: The analog sections on the DEQ2496 is not the best unless modded, use only digital I/O)

Run it between digital source and DAC. It can be had for $275 to 300 new on Ebay, and if you try it and don't like it, you can re-sell it rather easily for $240-275. I buy several a year to integrate with my H1 speaker systems (you can see it at holisticaudio.com), so if you don't like it I may be interested as well. 

Try it, it is an outstanding solution for not much money.

Jack,

Thanks for the idea.  It definitely seems worth a try.  I'll look into it further.

What I've done in the meantime is go back to using an EQ'd sub for music.  After a lot of playing around and tuning, I have something that now sounds very good.  I know there is always better out there, so the idea of the DEQ2496 is interesting.