DSP: EQ’ing Full Range or Not – Testing the Ears

[markus]

I am sorry. what is DL?

DL = Dirac Live

 

[teyhyrh4r]

DL = Dirac Live

I don't know what it realy does, but afaik the target is aplied to a broad-window meassurement.

 

[markus]

I don't know what it realy does, but afaik the target is aplied to a broad-window meassurement.

Plenty of details at https://www.dirac.com/

 

[Sonnie Parker]

Here's the .mdat for those interested.

 

[markus]

Here's the .mdat for those interested.

Thanks. The data suggests that the anechoic response did indeed improve. For more conclusive results the anechoic speaker response would need to be measured with and without Dirac Live.

 

[AJ Soundfield]

if the system is direct sound dominant, it is obvious that a full correction will make it more balanced.
now a reverbant system can look messed up in the LP meassurement, while in reality having a fully balanced direct sound. in this situation you would make things worse with the full correction

For more conclusive results the anechoic speaker response would need to be measured with and without Dirac Live.

Yes.
Thank you both.

 

[teyhyrh4r]

as I have shown here: https://www.hometheatershack.com/th...dependent-windowing.99673/page-6#post-1619293
FDW can be used to filter out the reverbant sound BUT(!) you have to create the minimum phase version of your meassurement first. else you have dips anywhere where the direct sound is delayed, because the frequency simply "fell out" of the window.

Denis Sbragion's DRC (which I use for my system) does this,
and Acourate probably, too

 

[markus]

FDW can be used to filter out the reverbant sound

That's not the only way to do this. Anyway, the thread title is highly misleading as "EQ’ing Full Range" with digital room correction product A can be very different from "EQ’ing Full Range" with digital room correction product B. Depends what kind of processing is actually applied. Quite a good overview can be found at https://www.mdpi.com/2076-3417/8/1/16/pdf

 

[Sonnie Parker]

That's not the only way to do this. Anyway, the thread title is highly misleading as "EQ’ing Full Range" with product A can be very different from "EQ’ing Full Range" with product B. Depends what kind of processing is actually applied. Quite a good overview can be found at https://www.mdpi.com/2076-3417/8/1/16/pdf

There is nothing "highly" misleading about the thread title. Unfortunately we don't break down all the details in the thread title... but the thread has everything to do with EQ'ing full range. We did not include the name of product A, B, C, and D because it would have made the thread title too long. It all makes very good sense if you read the opening thread.

It not only comes down to the speaker, but it also depends on the room as well, which is mentioned in the opening thread.

 

[markus]

There is nothing "highly" misleading about the thread title. Unfortunately we don't break down all the details in the thread title... but the thread has everything to do with EQ'ing full range. We did not include the name of product A, B, C, and D because it would have made the thread title too long. It all makes very good sense if you read the opening thread.

It not only comes down to the speaker, but it also depends on the room as well, which is mentioned in the opening thread.

Huh? You've used DL for all tests, no? Hope you don't assume that any EQ approach would be the same and the only difference is "full range" vs. "limited"? That would be a major misconception.

 

[Sonnie Parker]

Huh? You've used DL for all tests, no? Hope you don't assume that any EQ approach would be the same and the only difference is "full range" vs. "limited"? That would be a major misconception.

You are making some very glorious assumptions yourself Markus... and I really don't have time to waste defending what we did. If you are going to do nothing but have the kind of attitude that cast doubt on everything we do, it might be better you move on back to AVS where you can be a star. If you have something positive and constructive to add, please do... otherwise move on. Your condescending attitude is getting rather tiring.

We, nor the thread title insinuates that you could use any EQ'ing system on planet earth, nor did we insinuate that Dirac Live is the only EQ'ing system you can use. This was a very simple evaluation we did while evaluating the 4 speakers, and we just happened to be using Dirac Live. The original thread notates what we were doing and what we were using, and anything thinking that this applies to every room, every speaker and every EQ system is truly closed minded. As with anything we do in the industry, YMMV with all aspects of the evaluation. We don't control what people might think is implied in what we do, we trust as with anything that they will research and figure it out, using this evaluation only as a suggestion, not something chiseled in stone.

 

[tonycdk]

There are a few well respected individuals out there that tell us not to EQ above 500Hz, that we may be doing more harm than good when we do.

First a real-life story. Many, many years ago, when I was using Tact 2.2Xs in my system, I sensed a problem with the correction and, as a result, I spent a lot of time on measurements and analyses to understand why. It turned out that the Tact was performing no correction in the frequency range of about 2 kHz to 5 kHz ( I do not remember the exact frequency range as it was so long ago). It was not until after Boz sent me his master copy, which was OK, that Boz finally recognized the problem. My best understanding is that a speaker manufacturer wanted to use the Tact to handle room issues in a show, but wanted the 2-5 kHz region untouched. It would seem clear that the speaker “house sound” was in the 2-5 kHz range and that the manufacturer did not want to destroy the “house sound”. This version of the software had been inadvertently set as the standard release. The Tact software was immediately updated to the correct version.

It must be obvious that, at the time, I could hear the difference between no correction in the upper frequencies and correction. I had an obvious preference for full range corrections. I continue to correct full range and have been using Acourate generated filters since 2006.

It seems to me that those who think that one should not correct above about 500 Hz are really saying that they have selected their systems based upon liking a particular “house sound” and don’t like losing it.

One can, of course, set the frequency target curve to be anything one likes but full range correction tends to balance the frequency response of the speakers and this improves imaging stability. Imaging information is not in the less than 500 Hz range.

 

[Eric SVL]

@Sonnie, am I reading those graphs right, that your response around 500 Hz sees a rise when you move further away from the speaker? Any idea what in the room would be causing that? I have a similar phenomenon that does not appear in the Klippel measurements so maybe it's the floor or ceiling.

 

[Erik Arisholm]

I know it is all subjective and based on personal preferences but I am surprised how many seem to prefer the "Harman" type bass boost of something like +10dB (or even more!) in the low end compared with 1kHz. Never liked that except for action movies. But I suppose those things also depends on the time domain behaviour, which is not much discussed here.
As for full-range vs partial correction, I have 7.1.4 movie system in a fairly small room (4mx7m) corrected full-range (with Lyngdorf RoomPerfect) and it is great, but then in the (much larger) living room my stereo system sounds best being corrected to about 500Hz (with Audiolense single measurement). In the latter case it sounds "dull" if I correct much higher. But that is with horn loaded speakers (Westminster) and perhaps that is the reason... Or perphaps because there are less "early" reflections in the living room due to size. BTW I don't want my living room to sound like it is my much smaller and well-damped movie room because that would just be strange... and I speculate that the reason is that the reflections have to travel more than 10m (and with horns to start with), it is not so much to correct further up.. just a guess ;-)

 

[teyhyrh4r]

I am surprised how many seem to prefer the "Harman" type bass boost of something like +10dB (or even more!) in the low end compared with 1kHz. Never liked that except for action movies. But I suppose those things also depends on the time domain behaviour

yea, most subs are aligned a full cycle late. full range speakers also have rising group delay in bass. both will mask the transients (loss of punch).
but this can't be the only reason. I suspect most harman boost users listen in lower level loudness, so the boost comes in handy to counter the equal-loudness contour

 

[teyhyrh4r]

my bass is flat. and I use loudness compensation calibrated to -14LUFS music. one of Spotify's updates broke the normalization for me, so suddenly it got stuck at -11LUFS (loud setting). I din't realized this, but I noticed the bass starting to annoy me. the 3LUFS louder music resulted in 1.5dB-ish bass boost (because of the added -3dB compensation). so a simple 1.5 boost messed up the balance for me

 

[Erik Arisholm]

my bass is flat. and I use loudness compensation calibrated to -14LUFS music. one of Spotify's updates broke the normalization for me, so suddenly it got stuck at -11LUFS (loud setting). I din't realized this, but I noticed the bass starting no annoy me. the 3LUFS louder music resulted in 1.5dB-ish bass boost (because of the added -3dB compensation). so a simple 1.5 boost messed up the balance for me

Yes so I bet your decay and other time domain graphs would also look pretty good in that case... no disrespect to anyone as I also like that lovely deep bass hitting me hard, but I think too many hifi-nerds who love bass have not yet heard the impact of properly time aligned and punchy bass,so they go for more volume instead. resulting in +10dB on the subs instead of getting the timing right.... IMHO...

 

[teyhyrh4r]

Yes so I bet your decay and other time domain graphs would also look pretty good in that case

yes, my system is DSP corrected in the time domain.

I remember Bob Katz posting on the subject one day. He said he had a little boost in the bass (not a crazy harman one), but got rid of it once he had his subs properly aligned

 

[Eric SVL]

I know it is all subjective and based on personal preferences but I am surprised how many seem to prefer the "Harman" type bass boost of something like +10dB (or even more!) in the low end compared with 1kHz. Never liked that except for action movies. But I suppose those things also depends on the time domain behaviour, which is not much discussed here.

It actually sounds balanced to my ears. The key is that your sub bass slopes down into the upper bass by ~120-150 Hz at most. The standard Harman curve continues to boost higher than that and in my experience does not sound as clean.

Not sure what you mean by time domain behavior. Of course we are assuming that you've taken care of delay and phase relationships so you have a smooth response.

 

[Erik Arisholm]

Not sure what you mean by time domain behavior. Of course we are assuming that you've taken care of delay and phase relationships so you have a smooth response.

By time domain behavoir I simply mean all the bass from the very low to the very high hitting your chest at about the same time, so that you physically can feel the kick, as opposed to just massive bass rumbling around in your room for too long, and starting at different times. And then there is the decay. The bass has to stop quickly too, to make this experience complete and that depends on the room properties (dimensions and absorbtion). I do not have the perfect system myself, by far, but as I said, I think too many people are crancking up their subs instead of getting them to kick at the right time and phase with their mains. Sooo much can be achieved there, with simple means (just correct delay/phase). And then some room correction afterwards... And preferably some really good bass traps to get the decay times down to reasonable levels (at least 20dB down within 100ms or so is in my experience really really good below 80Hz, but still fine with -20db after about 150ms. 200-300ms range? typical room and not so good). But we are a bit off topic, sorry about that :-)

 

[Eric SVL]

By time domain behavoir I simply mean all the bass from the very low to the very high hitting your chest at about the same time, so that you physically can feel the kick

Achieving a smooth frequency response is the result of managing delays and equalization and is talked about all the time with regard to subwoofers.

as opposed to just massive bass rumbling around in your room for too long, and starting at different times. And then there is the decay. The bass has to stop quickly too, to make this experience complete and that depends on the room properties (dimensions and absorbtion).

This is bass decay. Step one is delays and equalization to smooth the response which greatly enhances bass decay. What's left below 100 Hz (from the room, etc) probably can't be changed by absorption, but from 100 Hz and up can to various degrees of success.

I think too many people are crancking up their subs instead of getting them to kick at the right time and phase with their mains. Sooo much can be achieved there, with simple means. And then some room correction afterwards...

I think you're mixing things up here. You're right that if people don't properly integrate their subs they're not going to get the best experience - but room correction is part of that, not separate from it.

 

[Erik Arisholm]

Achieving a smooth frequency response is the result of managing delays and equalization and is talked about all the time with regard to subwoofers.

This is bass decay. Step one is delays and equalization to smooth the response which greatly enhances bass decay. What's left below 100 Hz (from the room, etc) probably can't be changed by absorption, but from 100 Hz and up can to various degrees of success.

I think you're mixing things up here. You're right that if people don't properly integrate their subs they're not going to get the best experience - but room correction is part of that, not separate from it.

Yeah I think we mostly agree, except I don't think I am mixing things up too much. The main point I tried to make is that there is a difference between the frequency domain correction most people are concerned about, and the resulting measurements they look at, and the more complex picture, meaning also considering how the sound pressure increases and decreases at differenent frequencies as a function of time in a typical room. Both can to a certain extent be corrected with DSP, but typically the frequency domain more so than the time domain unless you allow for long filters and thus large latencies. Time domain correction depends on the SW capabilities and the acceptable max latency for a given situation. I think currently only Audiolense, Accurate and possibly Trinnov corrects the time domain with proper user adjustments, please suggest others if I missed any

 

[Eric SVL]

Yeah I think we mostly agree, except I don't think I am mixing things up too much. The main point I tried to make is that there is a difference between the frequency domain correction most people are concerned about, and the resulting measurements they look at, and the more complex picture, meaning also considering how the sound pressure increases and decreases at differenent frequencies as a function of time in a typical room. Both can to a certain extent be corrected with DSP, but typically the frequency domain more so than the time domain unless you allow for long filters and thus large latencies. Time domain correction depends on the SW capabilities and the acceptable max latency for a given situation. I think currently only Audiolense, Accurate and possibly Trinnov corrects the time domain with proper user adjustments, please suggest others if I missed any

But they are interrelated. Adjusting delays affects the frequency response.

 

[Erik Arisholm]

This is bass decay. Step one is delays and equalization to smooth the response which greatly enhances bass decay. What's left below 100 Hz (from the room, etc) probably can't be changed by absorption, but from 100 Hz and up can to various degrees of success.

With my new 20" ASC Isothermal tubetraps I achieved significant improvements down to about 40Hz or so in terms of decay times. And exceptional results around 80Hz where it really matters. Not so with my earlier "bass traps" from GIK etc:-)

 

[Sonnie Parker]

We are certainly not overlooking timing/delay... and Dirac fixes that with complex algorithms much better than we can. Mitch with Accourate Sound can fix it as well, he has all the right tools to do so. The bass hump has nothing at all to do with compensating for poor alignment... it is simply what most people prefer to compensate for the hearing loss down low (Fletcher Munson curve). If you don't like the compensation, then you simply like less bass, although you aren't really hearing a flat response if you don't compensate for it. IMHO... it is less accurate, but hey, to each his own.