Corner Bass Traps - Always beneficial?

[microstrip]

---Micro, then perhaps you need better loudspeakers, with better controlled bass. :b

...And some fine-tuning with a top-notch digital Room EQ. ...Like one included with a quality sub, or two. ...Or from a separate box (TacT, Trinnov, Audyssey, JBL Synthesis, Real EQ, ...).

Bob,

These are general findings that I associate with my room when using any full range box speakers - and they were more than half a dozen during the last five years, weighting between 100 and 300 lbs.

I always escaped from trouble rejecting them after some time and coming back to the gargantuan Sound Labs A1 Px's. They are very large full range dipoles about 2 square meter each, I could cancel the more disturbing room mode positioning them in a way their back wave cancelled the mode, and they did not have significant bass bellow 27Hz. But I feel the Sonus Faber Aida's deserve my efforts. They are such a great speaker that I really want to keep them. I already managed to control the bass using other amplifiers, such as the Devialet, but I think that the proper choice would be to correct the room before trying any other approach - otherwise FrantzM will not forgive it . I also have two Descent I and a Behringer DCX2496 waiting for my time,

 

[NorthStar]

---Micro, I was awared that you have access to top-notch loudspeakers and electronics.

But in general, people from your 'bracket' caliber are the ones most in need to perform the Art of balancing everything with their 'music' room. :b ...Or perhaps I should have said; the ones in constant search to 'sound reproduction' perfectionism. :b

Keep at it till you drop! ...It's fun anyway.

* By the way; Sonus Faber Aida's, Devialet Premier amplification, and two Descent subs are truly worthy to make things 'gel' perfectly in your room. :b
- In top of bass traps, acoustical panels for the higher frequencies, have you try high-end Room EQs like the ones I mentioned above? ...Or is the Behringer DCX2496 enough (which I doubt)?
Anyway I am 100% certain that your overall 'sound' is mucho bettero than my overall 'sound'.
But the thing that I am truly satisfy about, in my own entourage, is the music quality of higher emotional impact; my musical listening selections, and the overall upbringing of joy. :b

I am also satisfy, for the moment, with Audyssey MultEQ XT Room EQ & Calibration for both Stereo & Multichannel music (SACDs). ...And movies too of course (with some additional and judicious manual adjustments; like in the surrounds for example, according to the material).

Personally, I found that way too many movies aren't up to the challenge in the pursuit of best sound. ...Most of them, except few very good ones.

As for music, it is better; Stereo wise and Multichannel wise.

Perhaps the film studios can take a good hint from some of them music recordings.

* As just an aside, I love the music score of 'Tron Legacy'. ...7.2-channel in my own room.
[The .2 is actually the bass reproduced by my two subs and comin' from all the other seven channels plus the LFE channel all reunited together as one fabulous and balanced entity].

 

[Nyal Mellor]

Rutgar and Microstrip...not sure if you have read this but very pertinent to this conversation. Jeff mentioned it earlier in the thread...the acoustical measurement standards, the white paper Jeff and I co-authored. In the low frequencies (<250Hz) don't look at T60, look at FR and a time domain measure like a spectrogram, waterfall or spectral decay plot.

FR: Within +/-10dB at 1/24th octave, Within +/-5dB at 1/3rd octave. Note that this can be tightened to +/-2.5dB with VERY careful acoustic design and calibration but +/-5dB is the minimum. Also please note that 1/24th is good to pinpoint issues but 1/6th or 1/12th is about the limit to our perception of timbral distortions so often I'm using those levels of smoothing now.

Time decay: Resonances from 35Hz-300Hz should not extend beyond 350ms before decaying into the noise floor or reaching a level of -40dB. Below 35Hz this standard is relaxed to 450ms.

 

[Rutgar]

Hi Nyal. Here is the spectrogram I did from 0 to 200hz.

 

[AudioExplorations]

Rutgar and Microstrip...not sure if you have read this but very pertinent to this conversation. Jeff mentioned it earlier in the thread...the acoustical measurement standards, the white paper Jeff and I co-authored. In the low frequencies (<250Hz) don't look at T60, look at FR and a time domain measure like a spectrogram, waterfall or spectral decay plot.

Nyal, VERY interesting paper, I was not aware of this but I will read through this with great interest and compare my own room measurements to the standards you propose.

 

[Nyal Mellor]

Hi Nyal. Here is the spectrogram I did from 0 to 200hz.

View attachment 4660

What do you think about how it compares to the standards we described?

 

[Rutgar]

What do you think about how it compares to the standards we described?

LOL! I was asking you. But, if I was to guess (using my lack of expertise), I think it looks like I'm doing fairly well in the time domain. But have a couple of nodal issues in the response realm.

 

[dallasjustice]

LOL! I was asking you. But, if I was to guess (using my lack of expertise), I think it looks like I'm doing fairly well in the time domain. But have a couple of nodal issues in the response realm.

Bill,
Did you think Nyal was going to let you off so easily?

 

[Rutgar]

Bill,
Did you think Nyal was going to let you off so easily?

I was hoping!

 

[NorthStar]

---Wishful thinkin'... :b ...The guy's here to learn!

 

[Nyal Mellor]

LOL! I was asking you. But, if I was to guess (using my lack of expertise), I think it looks like I'm doing fairly well in the time domain. But have a couple of nodal issues in the response realm.

Yep, that's pretty much it

I would look at the ~50Hz region which requires some further attention. But likely you can already see that quite clearly on the frequency response.

 

[Rutgar]

Yep, that's pretty much it

I would look at the ~50Hz region which requires some further attention. But likely you can already see that quite clearly on the frequency response.

Yeah, that area is looking quite nasty. I also understand that region can be very difficult to tame with room treatments.

 

[Nyal Mellor]

Yeah, that area is looking quite nasty. I also understand that region can be very difficult to tame with room treatments.

With that area you are right. I would start with speaker / listener position. If you are using subs then you can place those. Try and get things as flat as possible. Then the next place to look would be parametric EQ, especially if you have only one seat that you really care about. If you have multiples then you'll need multiple subs in specific mode canceling arrangements and maybe some EQ. Finally I'd look at acoustic treatment. About the only commercial thing that works properly down that low is RPG Modex Plates. You can build custom stuff that is very effective down that low too. Some other products have some absorption down at 50Hz but they are tapering off in effectiveness pretty fast.

 

[microstrip]

W(...) About the only commercial thing that works properly down that low is RPG Modex Plates. You can build custom stuff that is very effective down that low too. Some other products have some absorption down at 50Hz but they are tapering off in effectiveness pretty fast.

Nyal,
Are you referring to RPG metal plate membrane absorbers? They seem promising.
BTW, thanks for you help in this thread - I will take a few fresh measurements this weekend and post them. My main concern now is the too long decay at 18 and 35 Hz.

 

[Nyal Mellor]

Nyal,
Are you referring to RPG metal plate membrane absorbers? They seem promising.
BTW, thanks for you help in this thread - I will take a few fresh measurements this weekend and post them. My main concern now is the too long decay at 18 and 35 Hz.

Yep, the metal plate absorbers. Please reference the reduced targets for decay time at the lower frequencies. Also note the <25HZ long decay times are not typically modally related.

 

[Rutgar]

Looking at the RPG Modex line, it appears there are lots of options and variables. But as all RPG stuff, it is pricey.

 

[dallasjustice]

Looking at the RPG Modex line, it appears there are lots of options and variables. But as all RPG stuff, it is pricey.

Ya, but at least they get it to you in 2-3 months.

 

[Nyal Mellor]

Ya, but at least they get it to you in 2-3 months.

Well the way I like to explain it is that it is no different than custom furniture for your family room

 

[Nyal Mellor]

Looking at the RPG Modex line, it appears there are lots of options and variables. But as all RPG stuff, it is pricey.

I guess it depends on the context of the rest of your system. Rooms are IMO the largest influencers of what you hear after speakers. So it would be speakers --> room --> everything else a lowly third.

 

[microstrip]

Yep, the metal plate absorbers. Please reference the reduced targets for decay time at the lower frequencies. Also note the <25HZ long decay times are not typically modally related.

But in this case my room is 9.3m long, exactly half of the wavelength of the lower frequency with the long delay. And the frequency of the second one is just the double. It looks too precise to be a coincidence.