Room EQ - do we need it?

[Krunok]

This poll is about your opinion on room EQ: do we need it or not, does it work or not?

 

[Thomas savage]

You don’t need it but I can’t see a negative for having it beyond the temptation to constantly arse about with it thusly distracting from drinking beer and listening to music.

Oh don’t ever stop conversation or anything else with a woman to adjust EQ, unless you want them to leave and or burn your dinner .

 

[Krunok]

You don’t need it but I can’t see a negative for having it beyond the temptation to constantly arse about with it thusly distracting from drinking beer and listening to music.

Oh don’t ever stop conversation or anything else with a woman to adjust EQ, unless you want them to leave and or burn your dinner .

I have done it and I must say I'm impressed with the results - they are better than I expected.

It was so long ago I have forgotten the time I learned not to discuss stuff related to my audio equipment and my car with women. I think I am now coming close to the age when I will prefer men company so I can freely discuss these things as sex will anyhow seem overrated.

 

[Kal Rubinson]

Sure. It's a great way to improve SQ. It ain't perfect but, of course, nothing is.

 

[Olli]

By far the biggest impact on my total system, apart from the speakers

 

[andreasmaaan]

Assuming that the direct sound from the speakers measures flat and that the speakers have a well-controller dispersion pattern, and that there’s nothing particularly unusual about the room layout and speaker placement, my interpretation of the studies is that room EQ is best used only in the modal region and not far above.

 

[Krunok]

Assuming that the speakers measure flat on-axis and have a well-controller dispersion pattern, and that there’s nothing particularly unusual about the room layout and speaker placement, my interpretation of the studies is that room EQ is best used only in the modal region and not above.

Maybe if you clarify this "modal region" term for the sake of us rookies in this area..

 

[Krunok]

By far the biggest impact on my total system, apart from the speakers

This is my experience as well. Yet it sems there are many folks who are not aware of this fact and are instead searching for better SQ by reducing THD from 0.0008% to 0.0003%.

 

[flipflop]

Maybe if you clarify this "modal region" term for the sake of us rookies in this area..

Pressure range: < 20-30 Hz
Modal range: 20-30 Hz to 150-200 Hz
Reverberent range: > 200 Hz

 

[Krunok]

I had to make corrections up to 300Hz but my room layout and speakers placement are not really ideal.

 

[andreasmaaan]

Maybe if you clarify this "modal region" term for the sake of us rookies in this area..

It depends on room dimensions, materials, and reverberation times, but yeh typically below 150-300Hz for most domestic living rooms (not including the pressure region at very low frequencies).

It’s the frequency range in which the room dominates the steady state frequency response, typically causing significant peaks and dips that vary depending on position in the room.

Writing while walking through the city so sorry if not all 100% accurate and kosher.

Edit: should have added that the transition point is extremely vague in a small room.

 

[Panelhead]

My previous dac offered it. Used the DRC and it was a large improvement. The process for DRC was Lyngdorf Room Perfect. It made integrating an offset single sub easy to the normal speakers.
Turning it off showed a large drop in sound quality. It performed single digit dB adjustment to amplitude from 20 - 500 Hz and some phase shifting too.
Would still be using it, except there was a non-defeatable hardware up sampler to get all files to 96/24 for processing. The upsampler was the issue, worked better if fed software upsampled 96/24, but it still recrunched the bits.
I have not tried the software solutions. Picking a mic and integrating is not easy to do correctly. I suspect it would improve sound quality. Hardware async resamplers are bad for SQ.
But happy for now with results from speaker placement and volume adjustments.
My room is both difficult and easy. It is a loft that overlooks 2 two story areas. Only has two walls. Lack of walls is an issue. But reflections from room are not a problem. Let’s the sound pressure out.
Room Perfect is designed for multiple microphone placement to learn the room. Once it thinks it has it at 90% it can stop acquiring data and calculate the amplitude and phase adjustments. I normally kept until room knowledge was 99%. The loft calcs were showed it as a difficult room.
Wish there was another “monitor controller” with updated DRC, microphone circuitry, sub woofer function, balanced outs, four channel volume control, and a calibrated microphone. FireWire and SPDIF too, which I consider a plus compared to USB.

 

[Cosmik]

A distinction needs to be made between speaker correction and room correction. If your speaker is one of the new breed of constant dispersion boxes, you will find that 'room correction' is a red herring.

The designer of the D&D 8C:

"No voicing required. Other loudspeakers usually require voicing. Based on listening to a lot of recordings, the tonal balance of the loudspeaker is changed so that most recordings sound good. Voicing is required to balance differences between direct and off-axis sound. The 8c has very even dispersion. It is the first loudspeaker I ever designed that did not benefit from voicing. The tonal balance is purely based on anechoic measurements."

If your speaker does not have constant dispersion, you need to make a compromise between flat direct sound and un-coloured room sound - the two are mutually exclusive in this case. So you may find that some EQ improves the sound in a particular room, but you are not correcting the room (which is impossible); you are partially correcting the speaker for use in that room.

 

[Panelhead]

Most solutions are DRC, Digital Room Correction. The room is a bigger issue than the speaker itself usually.
But starting with a speaker that is flat in response is a step in the right direction.
That D&D speaker would work fantastic if the listening room used was an anechoic chamber.

 

[andreasmaaan]

A distinction needs to be made between speaker correction and room correction. If your speaker is one of the new breed of constant dispersion boxes, you will find that 'room correction' is a red herring.

The designer of the D&D 8C:


If your speaker does not have constant dispersion, you need to make a compromise between flat direct sound and un-coloured room sound - the two are mutually exclusive in this case. So you may find that some EQ improves the sound in a particular room, but you are not correcting the room (which is impossible); you are partially correcting the speaker for use in that room.

Not meaning to rehash this one But I think there is some pretty good evidence that, while throughout most of the audio band we discriminate well between the direct and reflected sound, below a certain frequency (or range of frequencies) in a given room, this ability to discriminate tends to fall apart.

In this frequency range, whether we label what we're doing "room" or "speaker" correction (I think the former is an appropriate term if the speakers are anechoically correct and exhibit constant directivity - which FWIW the 8Cs do not), we are correcting the perceived tonal balance of the system in a range in which the room influences it - and indeed typically dominates it.

 

[Cosmik]

Not meaning to rehash this one But I think there is some pretty good evidence that, while throughout most of the audio band we discriminate well between the direct and reflected sound, below a certain frequency (or range of frequencies) in a given room, this ability to discriminate tends to fall apart.

In this frequency range, whether we label what we're doing "room" or "speaker" correction (I think the former is an appropriate term if the speakers are anechoically correct and exhibit constant directivity - which FWIW the 8Cs do not), we are correcting the perceived tonal balance of the system in a range in which the room influences it - and indeed typically dominates it.

So people say... but... my suspicion is that this transition is what we expect to hear; it is consistent with the reverberation at higher frequencies because it is caused by the same floor, walls and ceilings. If I modify one band so that it doesn't correspond with the rest (in terms of frequency and time domain), I break the consistency. Of course it will cause the expected nulls and peaks as you move around that will leap out in measurements, but will you hear them if you're not listening out for them? I don't think so.

My instinct is that this is something that people are doing because of measurements, not what they actually hear - and of course it's a nice puzzle to play around with. I still think that a large pair of three-way DSP'ed monkey coffins gives you a perfectly nice sound without resorting to multiple subwoofers etc., and my deep suspicion is that they are actually better because of their simplicity; as soon as people start breaking the system up into multiple extra distributed sources in order to patch together a flat frequency response at a region in space, I begin to doubt the integrity of the result - and that also goes for taking the backs off speakers, sawing holes and sticking tubes in the boxes, etc. I would like to hear the Grimm LS1 - which looks like a very simple design.

(I agree about re-hashing, but the topic was raised afresh and I just couldn't let it lie...)

 

[andreasmaaan]

(I agree about re-hashing, but the topic was raised afresh and I just couldn't let it lie...)

Fair enough

I think simplicity can be impressive or elegant, but - like complexity - it is never inherently good or bad for sound quality. I do agree that room EQ seems to often be done wrong and for the wrong reasons though.

And I'm also a fan of well-designed monkey coffins, well set up, in a good acoustic space.But I'm reluctant to rule out the possibility that a bit of bass management EQ and some well-integrated subwoofers wouldn't often improve on such a setup.

Slightly left-field question: given what you've said above, would you always be in favour of speakers having anechoicically flat bass? Or would you suggest that in a smaller room a gentle roll-off or shelf in the bass of a few dB (often framed as partial rather than full baffle step compensation) is preferable? The common wisdom seems to be the latter, but it seems to me that your position would suggest the former.

 

[Cosmik]

We have two opposing views (that people don't necessarily recognise consciously).

1. We must modify the source(s) so that what reaches the listener's ear is as close to a specified (smoothed) frequency response as possible (but not time/phase response because this is considered just 'de-correlated chaos'). OR
2. The speaker must be small (in relative terms) and neutral (anechoic frequency response, dispersion)

For (1), many, many different approaches can meet the goal including electronic EQ, phased arrays, reverse phase sources (even if that's just the backwave from the driver), resonators, acoustic panels. The aim is to patch together enough bits of frequency response material to fill the FFT bins to the right levels when making the measurement. A bit of a dip here? Change the value of that resistor, or aim that driver in a different direction. Ah, that looks better.

Whereas (2) is so simple that it gives the impression that it's either going to be right (perfect in fact) or vastly inferior to the patch-and-mend approach. If a convincing example of (2) can be found that people seem to love the sound of, it's an indication that it's probably right.

 

[Cosmik]

Slightly left-field question: given what you've said above, would you always be in favour of speakers having anechoicically flat bass? Or would you suggest that in a smaller room a gentle roll-off or shelf in the bass of a few dB (often framed as partial rather than full baffle step compensation) is preferable? The common wisdom seems to be the latter, but it seems to me that your position would suggest the former.

A fair point. As was mentioned earlier, you might even start getting into pressurisation at low frequencies - which is a special, not strictly acoustic, phenomenon. Also, things rattle and vibrate. So of course, even in my ivory tower, I would not be averse to the bass being rolled off at the very bottom end.

 

[bravomail]

if u cannot afford to make ur room ugly with sound absorbing panels, then try room EQ/phase adjustments. Best results achieved with DSP. My Yamaha 683 AV receiver has it. Cannot say that it makes a big difference in my case. It just overall- equalizes/levels/distances speakers, plus tries its best to room EQ. And ye u would achieve best results if this applied to subwoofer as well as speakers. 20-300Hz sounds right. I don't think Yamaha does proper adjustments for subwoofer. Pioneer's MCAC does, I think.