Polar response is not the key

[March Audio]

It is useful for others who are reading as this is a very important topic.

It is indeed but continuing contradiction of well established knowledge from an uninformed position isn't helpful to anyone

 

[Xulonn]

It is indeed but continuing contradiction of well established knowledge from an uninformed position isn't helpful to anyone

Many of the most informative posts in this thread are ignoring the blather. (If you don't know the meaning of the word - look is up - it's descriptive and not hard-core pejorative.)

Perhaps the originator of this thread will learn a bit in spite of his persistent resistance. I would guess that many others - like me - are learning a lot, and appreciate the contribution of knowledgeable posters and their intelligent debate. I am happy to put up with a bunch of blather to learn more about the very important and critical issue of speakers and room interaction. So far, in this thread, we have managed to avoid the anger, disruption, and distraction that often accompanies heavy-handed moderation. I think that this forum has handled these situations better than most that I have participated in over more than 20 years.

My own arrival at this forum was marked by a heavy-handed post by me that was intended as strong criticism and was interpreted as an attack on a long-time respected regular. I backed off, regrouped, and worked hard over the months to regain some respect from those initial errors - and seem to have been successful at crawling out of the deep hole that I created. Anyone who goes off the rails a bit here will likely be given the same opportunity to regroup and return to respectfulness.

 

[March Audio]

I think, like others that have similarly implied, that for the OP to make such specific statements about a clearly technical topic which takes a significant understanding of the area, and yet he apparently has performed no research or reading about it is very, very odd.

If you have no knowledge of the area why would you even start commenting on such a specific and technical area?

The question wasn't "what is the relevance and impact of polar response", it was a statement saying "polar response isn't relevant".

My point is not about avoiding the topic, it's about the worth of engaging with the OP on his terms. That's just someone arguing black is white.

 

[Xulonn]

My point is not about avoiding the topic, it's about the worth of engaging with the OP on his terms. That's just someone arguing black is white.

Point taken - the discussion of the subject at hand can continue in this thread without engaging the antagonist - even when he replies.

 

[Deleted member 2944]

The question wasn't "what is the relevance and impact of polar response", it was a statement saying "polar response isn't relevant".

Actually, he didn't say "...isn't relevant." He said "it's not the key." Two, different statements, in my opinion.

Anyways, the original post title is an interesting turn-of-phrase because it can be interpreted in a few different ways. That's actually one of the hallmarks of a good troll......to posit something that numerous readers will take in numerous different ways. "Audiojim" has a history of trolling various audio forums, so it's not unsurprising to see something like this here.

Taken literally, I don't disagree with the original statement. To me, "not the key" implies something that's not the #1 priority. In my opinion, polar response is not the #1 objective in successful speaker system design......but it's certainly not irrelevant.

Dave.

 

[March Audio]

Actually, he didn't say "...isn't relevant." He said "it's not the key." Two, different statements, in my opinion.

Anyways, the original post title is an interesting turn-of-phrase because it can be interpreted in a few different ways. That's actually one of the hallmarks of a good troll......to posit something that numerous readers will take in numerous different ways. "Audiojim" has a history of trolling various audio forums, so it's not unsurprising to see something like this here.

Taken literally, I don't disagree with the original statement. To me, "not the key" implies something that's not the #1 priority. In my opinion, polar response is not the #1 objective in successful speaker system design......but it's certainly not irrelevant.

Dave.

Nope, he said exactly that in the OP

"I believe that polar response is unfortunately not relevant"

II wasn't aware of his trolling track record you mention, but it fits precisely with my view of what he has posted and why. Also supports my reaction to hit the ignore button.

If you read the research of Toole et al the off axis response is crucial. This conclusion is entirely common sense in my view. What you hear is not just the direct sound from the speaker, it is a combination of direct and off-axis sound both of which then gets reflected from room boundaries. The overall radiated sound power is important. This is very clearly borne out by the research.

To try and rank it in numerical order of importance is a bit well misleading. Out of curiosity, what do you beleive is important and why?

 

[Juhazi]

#1 The benefits I mentioned are actually independent of the triangle size.

#2 can actually be considered a drawback of toe in. The toe in makes the side wall reflection response less similar to the response on the listening axis due to the directionality of the larger drivers compared to the smaller drivers. I would expect this difference to be more audible the closer the driver is to the side wall due to the shorter time delay difference between the listening axis and side wall reflection. Btw I understand your logic in that less driver output is radiated at the wall and I used to think the same but it’s only true in the upper end of the drivers radiation and Olive and Tooles research convinced me this would be more coloured

Yes, the frequencies above 1kHz are most critical and sensitive psychoacoustically - localization and timbre wise. Typical directivity of modern narrow speakers at more than 30¤ off-axis rises rapidly above 500-1000HZ and rather small rotations have great effect to reflected spectrum. So, tonality change towards "darker" is expected.

I have listened to mainly dipole peakers for the last six years, and they empasize this because with more toe-in, the rearside energy gets projected wider and to longer path (proportionally more of it), but without a change in tonality.

 

[Cosmik]

If you read the research of Toole et al the off axis response is crucial. This conclusion is entirely common sense in my view. What you hear is not just the direct sound from the speaker, it is a combination of direct and off-axis sound which then gets reflected from room boundaries. The overall radiated sound power is important.

Even this phenomenon is open to two interpretations, however.

1. To the person who believes the standard frequency domain audiophile model which says that the listener hears one 'stream' of speaker combined with room, and that phase and timing accuracy are pretty much obliterated by room reflections (mentioned earlier in this thread, and an oft-cited argument against some of my views about the time domain performance of speakers), this is slightly mysterious. To them, it should simply be possible to use a graphic equaliser to make the room/speaker combination flat. The off-axis versus on-axis discrepancy only results in a change in overall frequency response and so this should be correctable.

2. Off-axis versus on-axis frequency response difference only really makes sense as an uncorrectable problem to the small percentage of people who believe that we hear two 'streams': the speaker's direct sound and the room. i.e. that the listener reads the acoustics of the speaker and room by their time and frequency responses, not just frequency response. To them, it is crucial for the direct sound and the room sound to have been derived from the same frequency profile because if it isn't, the speaker's presence is being signalled by everything in the composite recording being passed through a single non-neutral dispersion characteristic, whereas in a live performance each source has its own dispersion characteristic that became part of the recording. We want this composite recording to be reproduced neutrally both off- and on-axis or we will hear colouration that cannot be corrected with any form of EQ or DSP.

Or another way of looking at it is that the room's time and frequency responses don't tally with the direct sound, and the listener picks up on this as colouration. Clearly this cannot be corrected by changing the direct sound because the room sound is derived from the direct sound. But most audiophiles don't believe in the 'time response' aspect at all, paying attention exclusively to the frequency response.

 

[March Audio]

Even this phenomenon is open to two interpretations, however.

1. To the person who believes the standard frequency domain audiophile model which says that the listener hears one 'stream' of speaker combined with room, and that phase and timing accuracy are pretty much obliterated by room reflections (mentioned earlier in this thread, and an oft-cited argument against some of my views about the time domain performance of speakers), this is slightly mysterious. To them, it should simply be possible to use a graphic equaliser to make the room/speaker combination flat. The off-axis versus on-axis discrepancy only results in a change in overall frequency response and so this should be correctable.

2. Off-axis versus on-axis frequency response difference only really makes sense as an uncorrectable problem to the small percentage of people who believe that we hear two 'streams': the speaker's direct sound and the room. i.e. that the listener reads the acoustics of the speaker and room by their time and frequency responses, not just frequency response. To them, it is crucial for the direct sound and the room sound to have been derived from the same frequency profile because if it isn't, the speaker's presence is being signalled by everything in the composite recording being passed through a single non-neutral dispersion characteristic, whereas in a live performance each source has its own dispersion characteristic that became part of the recording. We want this composite recording to be reproduced neutrally both off- and on-axis or we will hear colouration that cannot be corrected with any form of EQ or DSP.

Or another way of looking at it is that the room's time and frequency responses don't tally with the direct sound, and the listener picks up on this as colouration. Clearly this cannot be corrected by changing the direct sound because the room sound is derived from the direct sound. Most audiophiles don't believe in the 'time response' aspect at all, paying attention exclusively to the frequency response.

Well, my reading of the Toole research is that scenario 1 does not work. The changing of the direct sound FR doesnt work if the off axis sound is uneven. This does seem to tally with my own early and naive attempts to EQ speakers based on single point in room measurement.

My understanding is that if time delay is under a certain value the event is perceived as a single sound, becoming disparate when over a certain value. So you need to treat these seperately in terms of perception.

Time coherence (phase) at crossover will certainly affect both direct and off axis sound - and importantly in different ways. So I do believe you want time coherence at crossover.

 

[Cosmik]

Summarising it more succinctly:

If humans don't separate room from speaker, how can it matter whether dispersion is non-uniform as long as the frequency response is flattened at the listening position?

But if humans do separate room from speaker then the dispersion issue makes sense. The question then is: what is the purpose of 'room correction', and how can it work?

Both cannot be true: it is not possible for non-uniform dispersion to be a problem *and* for room correction to make sense as a concept.

 

[Juhazi]

If off-axis response (in 3D) and direct vs. power response difference were irrelevant, we wouldn't have so many different speakers and opinions of how they sound in a room! But our psychoacoustic binaural hearing in a room is so delicate that we really do hear even very little differencies in speakers, even blindfold!

The early Harman studies of speaker response/room curve were done with a single speaker in a damped room. Only much later on they develeoped a standardized listening room with multichannel setup. I think that we still need more controlled studies with stereo pairs in a room, not just random opinions.

Regarding the sanity of room-eq-correction, I prefer speaker/spot positioning and "room treatment". Signal manipulation with IIR or FIR "corrections" alters all radiated sound and if used must be done very delicately and it still helps mainly in modal frequencies.

 

[March Audio]

Summarising it more succinctly:

If humans don't separate room from speaker, how can it matter whether dispersion is non-uniform as long as the frequency response is flattened at the listening position?

But if humans do separate room from speaker then the dispersion issue makes sense. The question then is: what is the purpose of 'room correction', and how can it work?

Both cannot be true: it is not possible for non-uniform dispersion to be a problem *and* for room correction to make sense as a concept.

IMO "room correction" is only significantly beneficial for hitting those strong room modes, where the problem is large. The positives of dealing with this are overwhelming compared to leaving it alone. It can be a gross aberration. Also my understanding is that at those lower frequencies the issue is predominantly minimum phase, so can be dealt with. I am absolutely a Toole advocate, but one thing does jar and furrow my brow. The idea that we do not hear the long reverberation time of these room modes and its only the amplitude discrepancy that is important. I have no evidence to contradict this assertion of his, but still it is very counter intuitive .

However, in my experience subtle tweaking of FR in a broadband sense can at times be helpful even if it is not technically the best thing to do *IF* your off axis response not ideal.

I dont think the two concepts you describe are completely mutually exclusive in a real world practical sense (even if they are on a purely theoretical basis) as the final subjective effect of implementation is dependent on so many variables.

 

[edechamps]

I think, like others that have similarly implied, that for the OP to make such specific statements about a clearly technical topic which takes a significant understanding of the area, and yet he apparently has performed no research or reading about it is very, very odd.

I suspect @Audiojim reads a lot of "audiophile" magazines, and that qualifies as "research" to him.

If you have no knowledge of the area why would you even start commenting on such a specific and technical area?

Donning-Kruger, and in particular unconscious incompetence. If they are conditioned by audiophiles magazines and marketing, they might very well believe they know a lot about the subject, and might not realize that their entire evidence base is extremely distorted.

1. To the person who believes the standard frequency domain audiophile model which says that the listener hears one 'stream' of speaker combined with room, and that phase and timing accuracy are pretty much obliterated by room reflections

2. Off-axis versus on-axis frequency response difference only really makes sense as an uncorrectable problem to the small percentage of people who believe that we hear two 'streams': the speaker's direct sound and the room.

But most audiophiles don't believe in the 'time response' aspect at all, paying attention exclusively to the frequency response.

Yes this might seem like a paradox, but I believe that if you look at it quantitatively, not qualitatively, you might find that it's not a paradox after all. Room reflections involve delays of multiple milliseconds and more. These delays are typically much greater than phase shifts induced by other parts of the chain (speaker, electronics). So the answer to this conundrum is that the statement "time domain doesn't matter" is true only up to a point. (An observation that is self-evident when you think about it: no-one in their right mind would argue that a delay of 1 second is inaudible, for example.) Delays induced by electronics and speakers are below that threshold, while room reflections are above it. See also: precedence effect.

Another thing that is of crucial importance here is the fact that side reflections not only induce delays, they also induce inter-aural differences because they reach one ear before the other. This also explains why our brains can distinguish between reflections and direct sound, and it doesn't have anything to do with time response per se. Assuming that hypothesis is true, then we would expect our brains to be very good at separating side reflections from the direct sound, and less good at separating floor/ceiling reflections from the direct sound. Guess what: this is exactly what studies show. Toole's book contains lots of details about these studies and their findings.

But if humans do separate room from speaker then the dispersion issue makes sense. The question then is: what is the purpose of 'room correction', and how can it work?

Both cannot be true: it is not possible for non-uniform dispersion to be a problem *and* for room correction to make sense as a concept.

Room correction makes sense at low frequencies, where the brain cannot effectively separate direct sound from reflections, and the frequency response aberrations are huge. To my knowledge it has never been shown conclusively that room correction is effective above the modal region. So yes, they can both be true, they just don't hold over the same parts of the frequency spectrum.

 

[March Audio]

I suspect @Audiojim reads a lot of "audiophile" magazines, and that qualifies as "research" to him.



Donning-Kruger, and in particular unconscious incompetence. If they are conditioned by audiophiles magazines and marketing, they might very well believe they know a lot about the subject, and might not realize that their entire evidence base is extremely distorted.



Yes this might seem like a paradox, but I believe that if you look at it quantitatively, not qualitatively, you might find that it's not a paradox after all. Room reflections involve delays of multiple milliseconds and more. These delays are typically much greater than phase shifts induced by other parts of the chain (speaker, electronics). So the answer to this conundrum is that the statement "time domain doesn't matter" is true only up to a point. (An observation that is self-evident when you think about it: no-one in their right mind would argue that a delay of 1 second is inaudible, for example.) Delays induced by electronics and speakers are below that threshold, while room reflections are above it. See also: precedence effect.

Another thing that is of crucial importance here is the fact that side reflections do not only induce delays, they also induce inter-aural differences because they reach one ear before the other. This also explains why our brains can distinguish between reflections and direct sound, and it doesn't have anything to do with time response per se. Assuming that hypothesis is true, then we would expect our brains to be very good at separating side reflections from the direct sound, and less good at separating floor/ceiling reflections from the direct sound. Guess what: this is exactly what studies show. Toole's book contains lots of details about these studies and their findings.



Room correction makes sense at low frequencies, where the brain cannot effectively separate direct sound from reflections, and the frequency response aberrations are huge. To my knowledge it has never been shown conclusively that room correction is effective above the modal region. So yes, they can both be true, they just don't hold over the same parts of the frequency spectrum.

This is what I was trying to allude to above

 

[Audiojim]

"Audiojim" has a history of trolling various audio forums, so it's not unsurprising to see something like this here.

II wasn't aware of his trolling track record you mention, but it fits precisely with my view of what he has posted and why. Also supports my reaction to hit the ignore button.

So just because dreite says I have a history of trolIng, you believe him without questioning the veracity of this claim? That's a good indication that your views on the topic being discussed here are probably not well founded.

 

[March Audio]

So just because March audio says I have a history of trolIng, you believe him without questioning the veracity of this claim? That's a good indication that your views on the topic being discussed here are probably not well founded.

I didn't say, dreite did, but it fits. It seemed exactly like a statement to provoke a reaction and was considered that way by multiple members.

If not I think the advice within the first few posts is very apt. You need to go away and read up on some of the texts mentioned before making claims and arguing about them as if you are informed on the subject. I'm sure you can see how it comes across otherwise.

 

[Audiojim]

I suspect @Audiojim reads a lot of "audiophile" magazines, and that qualifies as "research" to him.

I do, but I try to read reviews with measurements such as stereophile. I supect that you are not actually an audiophile but just care about measurements and research. You have to understand music just as much as the measurements if you want to really understand sound quality.

 

[daftcombo]

pply some low frequency positive shelving below ~ 250Hz to target the Harman trained listener target attached.

Why not above?
The 'trained listener" curve goes down of 10dB between 20Hz and 20kHz.

 

[March Audio]

I do, but I try to read reviews with measurements such as stereophile. I supect that you are not actually an audiophile but just care about measurements and research. You have to understand music just as much as the measurements if you want to really understand sound quality.

The point is that the research of Toole does define the correlation between subjective opinion and measurement. It does this with amazing accuracy. They could predict from measurement in an anechoic chamber which speakers would be preferred when listened to under blind controlled conditions. It also demonstrated how utterly useless and inaccurate sighted comparison and assessment of speakers is.

Specifically that speakers with flat and smooth on axis anechoic response and smooth off axis response were preferred subjectively.

Two lectures for you to digest

Start at 8 minutes

 

[Audiojim]

The point is that the research of Toole does define the correlation between subjective opinion and measurement. It does this with amazing accuracy. They could predict from measurement in an anechoic chamber which speakers would be preferred when listened to under blind controlled conditions. It also demonstrated how utterly useless and inaccurate sighted comparison and assessment of speakers is.

Specifically that speakers with flat and smooth on axis response and smooth off axis response were preferred subjectively.

show me the paper so that I can read this.