Testing whether the speakers work as intended?

Vinterbird

Vinterbird

Enthusiast
Hi everyone,

I have a very basic 3.0 speaker setup using the Elac UniFi series. Recently I've had a lot more time to actually sit and listen, and I think there is something wrong with my right and center channels, but I am not sure how to actually determine it, so I can communicate the defect / issue properly to the shop and have them fixed.

Is there a prefered way of testing all parts of a speaker in order to determine if they perform as intended?
 
Kvn_Walker

Kvn_Walker

Audioholic Field Marshall
What is it you think is wrong? Static or popping in the drivers? Does the right sound lower than the left? Do you hear it all the time, or only in certain music or movies?

You can play tones at different frequencies to try to isolate a specific driver as being faulty. Also double check your wiring of course, and swap speakers to different channels to make sure it's not an amp/receiver issue.

If they're under warranty I don't suggest opening them for any inspection, but there's plenty you can troubleshoot from the outside.
 
TLS Guy

TLS Guy

Seriously, I have no life.
You need to move the speakers around for a start and see if the fault moves with the speaker or the amp channel. You don't know of it is a speaker or receiver problem otherwise.
 
R

Russdawg1

Full Audioholic
Hi everyone,

I have a very basic 3.0 speaker setup using the Elac UniFi series. Recently I've had a lot more time to actually sit and listen, and I think there is something wrong with my right and center channels, but I am not sure how to actually determine it, so I can communicate the defect / issue properly to the shop and have them fixed.

Is there a prefered way of testing all parts of a speaker in order to determine if they perform as intended?
Sweeping each individual speaker with a calibrated mic will give you graphs to compare and see if it truly is the speaker. This is unorthodox but is one of the most definite ways to tell.

But like others have said, are you sure it’s the speakers?
 
Swerd

Swerd

Audioholic Warlord
Sweeping each individual speaker with a calibrated mic will give you graphs to compare and see if it truly is the speaker.
Instead of providing a useful answer to a new owner, this advice could easily lead to confusion. A frequency sweep might work, but you must also have a frequency response graph showing how those speakers should perform.
 
R

Russdawg1

Full Audioholic
Instead of providing a useful answer to a new owner, this advice could easily lead to confusion. A frequency sweep might work, but you must also have a frequency response graph showing how those speakers should perform.
I meant that he would compare the graphs, because he said that only his right and center sound “off”.
 
Matthew J Poes

Matthew J Poes

Audioholic Chief
Staff member
Instead of providing a useful answer to a new owner, this advice could easily lead to confusion. A frequency sweep might work, but you must also have a frequency response graph showing how those speakers should perform.
I think his advice is fine. If I was trying to diagnose a speaker that I didn't think was working properly, I would absolutely run a sweep on it with something like REW. I don't need the original data because if something is wrong, it will be evident. With a Sine Sweep measurement, I would be able to not only see its response but also distortion. I have diagnosed a number of bad speakers for folks on forums by having them send me their measurement files. Often what you see is the tweeter is bad (or a part in the tweeters path) and so the response shows either a very poor treble response or no treble at all. Other times, the response looks ok, but the distortion is really elevated. If this isn't true of all the speakers, just certain ones, it becomes pretty clear that something is wrong with those speakers. If this is true of all of them, well, something is still wrong, but it may just be a bad speaker design.

The Old AJ designed Pioneer speakers are a good example of a speaker that when measured at somewhat elevated levels (around 90dB at 1 meter) show elevated distortion in the treble across the board. It's just a design issue. KEF is a good example of a brand whose speakers more frequently show bad tweeters. I can't say why, but my guess is that by co-locating the tweeter inside the voicecoil the tweeter is not as robust. The cooling is probably worse, including being heated by the woofers coil, as well as having a smaller voicecoil itself.

Probably the biggest issue with this advice is that someone new to the forum and probably measurements not only can't run a sweep, but may have trouble figuring out how. I suspect that just listening to test tones or sweeps and using your ear might give you good information too. That might be a better solution for now.
 
Swerd

Swerd

Audioholic Warlord
I think his advice is fine. If I was trying to diagnose a speaker that I didn't think was working properly, I would absolutely run a sweep on it with something like REW. I don't need the original data because if something is wrong, it will be evident.
It's fine if you know what you're doing. If you've never run a sweep before, and never looked at frequency response graphs of speakers in real rooms, you'll be confused by those disturbing looking peaks and valleys below ~250 Hz.

I know one speaker maker, Dennis Murphy, who often wishes his customers never heard of REW.
Probably the biggest issue with this advice is that someone new to the forum and probably measurements not only can't run a sweep, but may have trouble figuring out how. I suspect that just listening to test tones or sweeps and using your ear might give you good information too. That might be a better solution for now.
I agree.
 
Matthew J Poes

Matthew J Poes

Audioholic Chief
Staff member
I know one speaker maker, Dennis Murphy, who often wishes his customers never heard of REW.
Hah, it's funny because its true!

With AV Nirvana being the official support source for REW, you can imagine we get a lot of the new users over there. I'm totally fine with new users who are trying to figure it out and ask a lot of questions. That is our job, and I happily help. What really throws me are the guys that come in with pseudo expertise who either use REW and insist something is wrong with it (the software), their mic, or....That their speakers are broken and in need of fixing. They then EQ them to within an inch of their life and proclaim all is well. Share the results, and...those of us who actually understand this stuff die a little inside.

I can't count the number of times I have had to explain why you shouldn't EQ a speaker above 300-500hz (and not really much above 100hz). The most common response I get is...Why not? Isn't that what we hear? Nope! That is not what you hear, and that is why you shouldn't EQ it.

REW is an amazing free tool, but there is no denying that it has caused a lot of problems too. Besides keeping a lot of good people up at night for no good reason, it's lead to a lot of misunderstanding. In my own presentation on REW I actually try to dispell some common REW myths and talk about graphs people should stop interpreting. Like Waterfalls! Please everyone who reads this, stop using them. If you want to know why, go watch my video. They are probably contributing more to confusion and misinterpretation than any other measurement graph (and there are particular acoustic experts who, quite frankly, are making this problem so much worse than it needs to be due to their own misunderstanding).

But I digress....To the OP, please look for some test tones or websites with test tones, especially frequency sweeps and try listening to those. Listen first through headphones. Once you have a sense of what the sweep should sound like, listen to a speaker you think is good, then a speaker you think is bad. You can most easily do this by swapping speakers. Only listen to one speaker at a time, it will be hard to tell what is going on with multiples playing. That should at least help you narrow down the problem a bit.

It might help to mention the general area you live, as someone on this forum may live nearby and be able to take measurements.
 
Verdinut

Verdinut

Audioholic Spartan
Someone with insufficient knowledge of loudspeaker behavior using REW may be expecting to see a very close to flat frequency response.

The fact is that an almost absolutely flat frequency curve as found with good amplifiers is unattainable with speakers, and he may figure out that the driver being tested is not a good performer while it's exactly the opposite.
 
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S

shadyJ

Speaker of the House
Staff member
Someone with insufficient knowledge of loudspeaker behavior using REW may be expecting to see a very close to flat frequency response.

The fact is that an almost absolutely flat frequency curve as found with good amplifiers is unattainable with speakers, and he may figure out that the driver being tested is not a good performer while it's exactly the opposite.
Very few people would enjoy a system that measures flat in room at the listening position. Perhaps those with significant amounts of high frequency hearing loss would like that kind of sound.
 
Matthew J Poes

Matthew J Poes

Audioholic Chief
Staff member
Very few people would enjoy a system that measures flat in room at the listening position. Perhaps those with significant amounts of high frequency hearing loss would like that kind of sound.
or people who listen with their brains instead of their hearts.
 
JerryLove

JerryLove

Audioholic Samurai
Very few people would enjoy a system that measures flat in room at the listening position. Perhaps those with significant amounts of high frequency hearing loss would like that kind of sound.
What is the reasoning behind that statement?

I enjoy a live performance.

If we record a live performance that can be (and in some cases is) a "flat recording" (that is to say, the recorded frequency-volumes are what was actually at the mike position.

If everything is flat (neutral) at my listening position; that is the closest I will get to hearing it live.

Why would I dislike that? Will everyone dislike it in the same way?

The point of the gear is sound reproduction. If the reproduction is accurate but sounds bad; then I would tend to fault the production. If 100% of production is bad in the same way then we could assert that accurate reproduction is bad; but I'll need to see support before I accept that premise.
 
JerryLove

JerryLove

Audioholic Samurai
I can't count the number of times I have had to explain why you shouldn't EQ a speaker above 300-500hz (and not really much above 100hz). The most common response I get is...Why not? Isn't that what we hear? Nope! That is not what you hear, and that is why you shouldn't EQ it.
Would you care to expand on that? Last I checked: I hear from about 16KHz down. I've not really experimented with where the cut-off is on the bottom where "hearing" becomes "feeling"; but I'm not sure that's involved in your claim.

Let's say that I'm listening to a performance on a piccolo or xylophone. What are the primary frequencies I am hearing?
 
R

Russdawg1

Full Audioholic
Would you care to expand on that? Last I checked: I hear from about 16KHz down. I've not really experimented with where the cut-off is on the bottom where "hearing" becomes "feeling"; but I'm not sure that's involved in your claim.

Let's say that I'm listening to a performance on a piccolo or xylophone. What are the primary frequencies I am hearing?
I sense some Dr. Toole reasoning...
 
S

shadyJ

Speaker of the House
Staff member
What is the reasoning behind that statement?
The reason is your hearing is expecting some kind of acoustic effect of the room. You want a flat response from the equipment itself, and it wouldn't sound natural if it didn't have a flat response, but your hearing acclimates to the sound of any room it is in very quickly. Of course, room acoustics will add a tilt to that response among other alterations, so that it is no longer a flat response. Well, your hearing knows how it is supposed to sound adjusted for the acoustics of the room. You don't want to adjust the systems response to compensate for all the ways that room acoustics modifies, because the system wouldn't sound natural anymore.

Consider that you could have someone playing the violin in your room. You hear the violin performance through the room acoustics, in fact you expect to hear that and it would sound strange if the room wasn't modifying the sound of the violin playing. It would sound like a performance in an anechoic chamber, which is far from a natural sound. The same thing is true of sound systems. Your sound system wouldn't sound great in an anechoic chamber. You could have a totally flat response at your listening position from your sound system in an anechoic chamber (assuming your system has a flat response), but it wouldn't be very enjoyable.
 
JerryLove

JerryLove

Audioholic Samurai
The reason is your hearing is expecting some kind of acoustic effect of the room. You want a flat response from the equipment itself, and it wouldn't sound natural if it didn't have a flat response, but your hearing acclimates to the sound of any room it is in very quickly. Of course, room acoustics will add a tilt to that response among other alterations, so that it is no longer a flat response. Well, your hearing knows how it is supposed to sound adjusted for the acoustics of the room. You don't want to adjust the systems response to compensate for all the ways that room acoustics modifies, because the system wouldn't sound natural anymore.
So... when I'm in a room wearing headphones I don't like it?

Consider that you could have someone playing the violin in your room. You hear the violin performance through the room acoustics, in fact you expect to hear that and it would sound strange if the room wasn't modifying the sound of the violin playing. It would sound like a performance in an anechoic chamber, which is far from a natural sound. The same thing is true of sound systems. Your sound system wouldn't sound great in an anechoic chamber. You could have a totally flat response at your listening position from your sound system in an anechoic chamber (assuming your system has a flat response), but it wouldn't be very enjoyable.
That would seem to depend on how the violin was recorded.

If this is, say, a chamber recording, I won't hear a violin in my room; I'll hear a violin in a chamber in my room.

Also: I feel like you are juxtaposing echos with frequency coloration. Much of what makes "my room" is the rebounding sound. This would segue into a conversation about monopole vs dipole vs omnipole as well as the nature of off-axis sound and whether room treatments improve or hurt sound. I've owned variations of all three.

My experience doesn't match your claims. Can you point me at studies that would support them?

Also: can you please verify my understanding of your claim: If the room happened to leave the sound flat at my listening position I would be fine with it; but if the room altered the sound and I countered that alteration I would not like it?
 
Matthew J Poes

Matthew J Poes

Audioholic Chief
Staff member
So... when I'm in a room wearing headphones I don't like it?


That would seem to depend on how the violin was recorded.

If this is, say, a chamber recording, I won't hear a violin in my room; I'll hear a violin in a chamber in my room.

Also: I feel like you are juxtaposing echos with frequency coloration. Much of what makes "my room" is the rebounding sound. This would segue into a conversation about monopole vs dipole vs omnipole as well as the nature of off-axis sound and whether room treatments improve or hurt sound. I've owned variations of all three.

My experience doesn't match your claims. Can you point me at studies that would support them?

Also: can you please verify my understanding of your claim: If the room happened to leave the sound flat at my listening position I would be fine with it; but if the room altered the sound and I countered that alteration I would not like it?
What James is saying is basically correct. The research was conducted by Toole. Numerous studies have supported that view. While you can look up the various AES published articles, it’s probably easier to buy Tooles books and read those. They do a better job explaining it in lay terms.

None of this has anything to do with how the instrument is recorded. It has to do with how we perceive speakers in a room as compared to outside. A speaker that measura flat anechoicly will have a tilt in the response of about 1db per octave from 20khz to 20hz. That causes the bass at 20hz to be about 10dB hot. This tends to always be true in any domestic room. It’s caused by the reflections off the boundaries, which at low frequencies especially, combine with the steady state at the mic. Our ear hears it basically this way as well as our ear tends to only detect transient changes like this over several cycles at such low frequencies. It is a part of why the low frequencies we hear in a room are mostly room reflections rather than direct sound. The sound has enough time to reflect off multiple surfaces before our ear detects a transient change.

It’s also important to remember that the standard approach or taking in room measurements is not a very intelligent method. In the words of Toole, it’s a “dumb” method. That is, it’s just measuring the steadystate based on omnidirectional pickup at a single location. This isn’t how our ears here. The FFT method of analyzing that data further decides that data into frequency information differently from how our brain detects it, so again, this approach is not representative of exactly what we hear. At low frequencies where the room reflections are already a part of the steady state that we hear, it’s of no conciquence. This is why eq at low frequencies is ok. However as we move out of the modal zone and into the stochastic zone, the mic combines these reflections as if they are static. They are not, they are transient and their exact nature and position at any given moment changes slightly. Further, our ears are able to separate the direct sound from the reflections (but our measurements cannot). As such, applying eq above a certain point means changing a response based on bad data. Those measurements do not reflect what the ear is hearing. It is very likely you are doing more harm than good.

PEQ and normal measurements using normal processing like REW does cannot be used to do in-room full bandwidth eq. Toole, Geddes, and many others like them would further argue that no tools can do this and Dirac and Audyssey should not be used.

However, I have read all ir Diracs published papers in their algorithm and believe that it has merit. Their approach uses a number of spatially varied measurements to detect those aspects of the response that are caused by reflections and diffraction. It can then ignore those and look for those anomalies in the response that are spatially constant. There is a little more to how this happens, but the fact remains, it then applies EQ in a manner that can avoid those problems. Because of its use of mixed phase filters, you end up with essentially an inverse transfer function of the response accounting for those aspects of the response that you shouldn’t eq.
 
S

shadyJ

Speaker of the House
Staff member
So... when I'm in a room wearing headphones I don't like it?


That would seem to depend on how the violin was recorded.

If this is, say, a chamber recording, I won't hear a violin in my room; I'll hear a violin in a chamber in my room.

Also: I feel like you are juxtaposing echos with frequency coloration. Much of what makes "my room" is the rebounding sound. This would segue into a conversation about monopole vs dipole vs omnipole as well as the nature of off-axis sound and whether room treatments improve or hurt sound. I've owned variations of all three.

My experience doesn't match your claims. Can you point me at studies that would support them?

Also: can you please verify my understanding of your claim: If the room happened to leave the sound flat at my listening position I would be fine with it; but if the room altered the sound and I countered that alteration I would not like it?
There are a bunch of studies that cover this area, but one that really nails your questions is this one. It's a major paper. If you don't want to purchase it, you can still get the gist its contents from a google search about it, since there have been many articles written about it. The room causes a spectral tilt in the response that is what you expect to hear. if you are listening outdoors, that is a different scenario and your brain adjusts accordingly, and that would be like a flat response. If you countered the room response with your own alteration that gave the speaker an anechoic or outdoor response, I don't think you would enjoy that. This is covered in Floyd Toole's book as well, the third edition (well worth reading!)
 
JerryLove

JerryLove

Audioholic Samurai
What James is saying is basically correct. The research was conducted by Toole. Numerous studies have supported that view. While you can look up the various AES published articles, it’s probably easier to buy Tooles books and read those. They do a better job explaining it in lay terms.
I own the Acoustics and Psycoacustics of Speakers in Rooms, and have had brief interactions with the man himself (he posts on another forum, or used to at least). I've also done the bulk of the hearing training regimen he created as part of his studies.

The take-away I have from double-blind testing he conducted at HK was that the major issue with a negative effect was non-flat off-axis performance. I have even experimented with [purchased] speakers built around that premise by someone perhaps well described as an true believer in that regard

None of this has anything to do with how the instrument is recorded. It has to do with how we perceive speakers in a room as compared to outside. A speaker that measura flat anechoicly will have a tilt in the response of about 1db per octave from 20khz to 20hz.
You seem to be on a different subject. This is not about the speaker's performance. This is the statement I responded to

"Very few people would enjoy a system that measures flat in room at the listening position. "

Can you point me at something that indicates that a non-flat performance is preferable to one which exactly reproduces the source material at the listening position?

I also wonder if the anecdotal experience that might support that isn't training.

I know a lot of people who dislike classical recordings where the mics are near the instruments and then the orchestra is placed in mixing. They much prefer stereo (usually with head-shaped baffels) in listening positions in performance halls. I am quite the opposite. I often think that my experience being *in* the pit when the music was being performed compared to most other's experience being in the audience creates an expectation of what is "better".

Further: where I do listen to recordings with strong room influences (such as in a cathedral); I must prefer headphones or a heavily deadened room. I suspect I would very much like an anechoic chamber for listening; though I would not be surprised if flat would be an aquired taste. Too much time with non-flat changes the pallet.

It’s also important to remember that the standard approach or taking in room measurements is not a very intelligent method. In the words of Toole, it’s a “dumb” method. That is, it’s just measuring the steadystate based on omnidirectional pickup at a single location.
This feels a bit like a straw-man. You are arguing the conclusion by simply rejecting the premise.

As such, applying eq above a certain point means changing a response based on bad data. Those measurements do not reflect what the ear is hearing. It is very likely you are doing more harm than good.
This seems to tie into your earlier post rather than the one you are responding to here.

But I'm worried that you've just changed the goalposts.

You had "Nope! That [frquencies above 500Hz] is not what you hear "
You've said that EQing above 500Hz is bad, which I've asked for the reasoning for.
As I understand your reasoning in your more recent post, it's because "people take bad measurements". Is that an accurate understanding?

Indeed: didn't Toole's DB testing show in many ways the exact opposite? That speakers putting (measured) flat responses off axis were preferred over speakers which put (measured) non-flat off-axis response? How is this not at least a partial validation of a relationship between measured response and subjective listening preferences?

There's a vast gulf between "most people EQ wrong" and "EQing is bad".

PEQ and normal measurements using normal processing like REW does cannot be used to do in-room full bandwidth eq. Toole, Geddes, and many others like them would further argue that no tools can do this and Dirac and Audyssey should not be used.
Has he actually made that argument? Has he actually stated that no tool can measure sound usefully?

Did he do blind studies I'm unaware of that said the results of such EQ were universally bad?

However, I have read all ir Diracs published papers in their algorithm and believe that it has merit. Their approach uses a number of spatially varied measurements to detect those aspects of the response that are caused by reflections and diffraction. It can then ignore those and look for those anomalies in the response that are spatially constant. There is a little more to how this happens, but the fact remains, it then applies EQ in a manner that can avoid those problems. Because of its use of mixed phase filters, you end up with essentially an inverse transfer function of the response accounting for those aspects of the response that you shouldn’t eq.
I fear this paragraph includes things I have too little background with to agree or disagree.
 

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