• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Is transient response the most important thing for the perceived audio quality in a system ?

Is transient response important for a good perceived sound ?

  • 1. No , not very important - explain why

    Votes: 18 45.0%
  • 2. Yes, very important - explain why

    Votes: 22 55.0%

  • Total voters
    40

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
What is a speaker cone doing during the flat part of a square wave?

There are no flat parts, unless the slopes are also infinitely steep. So, if a cone finds itself on a flat it’s probably asking itself how it got there so fast :)
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,523
Likes
37,054
Here is a Quad ESL63 square wave courtesy of Stereophile.
1685062117343.png

And the step response.
1685062183772.png

That quasi-point source design must really work. Here is the impulse response.
1685062497306.png
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
I think you'll always be defeated by room reflections, if nothing else.

But we don’t accept high distortion in DACs or amps, just because we’ll have to deal with room effects later. We expect each part of the chain to be the best it can, and we strive to address shortcomings in performance at every stage. That goes for everything from recording to listening room.
 

levimax

Major Contributor
Joined
Dec 28, 2018
Messages
2,348
Likes
3,462
Location
San Diego
How do you know that? This is just one of an infinite number of possible signal shapes. If the speaker cannot reproduce this signal, what other signals will it be incapable of reproducing?
It is a fact that music does not contain anything like a square wave so what would be the point of worrying about reproducing one? If a speaker can reproduce 20 Hz to 20 Khz at a linear SPL that is all you need for listening to music. Chasing things that don't make a difference is a waste of time and money and learning what is important and what is not important is the value this site offers vs the "everything matters" audiophile myths.
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
It is a fact that music does not contain anything like a square wave so what would be the point of worrying about reproducing one? If a speaker can reproduce 20 Hz to 20 Khz at a linear SPL that is all you need for listening to music.

Well, I thought I pointed out that I’m not talking about square, but “square”, i.e. bandwidth limited. Like in the example signals I’ve shown. Any HiFi system that is designed to be transparent between 20Hz and 20kHz should be able to reproduce those.

Now, no system is transparent, every real system contains high- and low-passes. Phase distortion is therefore inevitable. Even a linear phase system, and of course a minimum phase system, will distort the square wave. But if the phase response is smooth these distortions will look ”nice”, like in these quick simulations:

Rolled off top end:
1685075482647.png


Falling phase throughout:
1685075563195.png


(the phase shift values are plucked out of the air, just for illustration)

That’s the sort of output you’d expect from a minimum phase system. I think these distortions of the signal shape are benign, since this kind of filtering happens in nature all the time. Our hearing would be accustomed to them. But if you see responses like this (again, completely made up):

1685075942742.png


then you can kind of guess that the speaker designer didn’t pay enough attention to phase response. Any composite signal (like music) that undergoes phase distortions like this will probably sound less real or convincing to our ears. This may also affect sound stage and imaging, who knows. There doesn’t seem to be enough research on this.
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
Here is a Quad ESL63 square wave courtesy of Stereophile.
View attachment 288237
And the step response.

Just for fun, I pointed the mic at my speakers and got this for a 1kHz square signal:

IMG_0625.jpeg


Not too bad, courtesy of Dirac Live :cool:

Without Dirac, it looks far less flattering:

IMG_0624.jpeg
 

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,891
Likes
35,912
Location
The Neitherlands
Dirac does a lot of correcting in this case.

It should be noted that what Tangband is talking about is not just upper FR and rise/fall time but transients 'first' wavefront that is of importance, not so much what happens after that (steady state signals). Marvin (SBAF) has been playing with this for a while.

see: https://www.superbestaudiofriends.o...urst-response-hd800-sr-207-hd650.3688/page-11

A bit like this:
index.php



index.php


When it is the first wavefront that is the most important (got the impression it is) then only the amplitude of the first part on the left is important for that 'impulse' aspect.

REW is capable of creating bursts for those that like to experiment. In the end it may well all come down to FR (for single driver headphones) but for speakers with XO and baffle mounted it may also be timing related.
 
Last edited:
OP
Tangband

Tangband

Major Contributor
Joined
Sep 3, 2019
Messages
2,994
Likes
2,789
Location
Sweden
Dirac does a lot of correcting in this case.

It should be noted that what Tangband is talking about is not just upper FR and rise/fall time but transients 'first' wavefront that is of importance, not so much what happens after that (steady state signals)

A bit like this:
index.php


see: https://www.superbestaudiofriends.o...urst-response-hd800-sr-207-hd650.3688/page-11

When it is the first wavefront that is the most important (got the impression it is) then only the amplitude of the first part on the left is important for that 'impulse' aspect.

REW is capable of creating bursts for those that like to experiment. In the end it may well all come down to FR (for single driver headphones) but for speakers with XO and baffle mounted it may also be timing related.
Good explaining by you. Yes , what happens at first wavefront is much more important than what comes after (later reflections from the room ) because its attenuated by the brain as much as 10 dB , very unsimilar to a microphone.
Many people at this forum thinks the microphone works similar as a brain with two ears , this is clearly not the case.
The mic takes up all the information, but the ear/brain selects sounds.

 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
REW is capable of creating bursts for those that like to experiment.

Yep, it was those REW tone bursts that proved to me that the Topping D90 XLR outputs were the wrong polarity (but the RCA outputs were correct). Up to that point I had wondered why my sub at the time (which ran off the RCAs) always integrated better when switched to 180º…
 

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,891
Likes
35,912
Location
The Neitherlands
That does not seem to something that can be fixed in firmware (without flipping the polarity of the RCA).
Has this been solved in the meantime ?

Would be a silly mistake from Topping and may need a polarity flipping XLR cable to fix it.
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
That does not seem to something that can be fixed in firmware (without flipping the polarity of the RCA).
Has this been solved in the meantime ?

Not sure. This was the original AKM non-MQA version. I believe the sockets are PCB mounted, so there isn’t much of a chance to screw this up during assembly.

I just flip polarity back at the speaker terminals.
 

Galliardist

Major Contributor
Joined
Jun 26, 2021
Messages
2,558
Likes
3,273
Location
Sydney. NSW, Australia
I find myself wondering what the issue actually is here.
Quite a bit of the debate may need modification because it considers instruments, but not that we are really listening to musicians manipulating instruments, and the sounds and timing of what the musicians do is what needs to be reproduced. It may be a matter of finer control of very small signal changes we are concerned with for that reason.

Then though, I find myself with a big "but".

Let's assume that we put a speaker in a reasonable room, with a usable front end and a sufficient amplifier, and play some vaguely well recorded music on it. When have any of you, in that situation, heard an issue that is clearly related to the attack part of an instrument's sound, or anything else that can clearly be caused by a transient? Even on "very poor" speakers, speech is usually distinct, you'll "pass the foot tapping test", you'll be able to tell what instrument is being played if it is being played solo, you can hear when the instrument starts and when it stops. Yes, we can point to "detail", but it's noted in threads here time and again that detail issues are related to frequency response and distortion.

Is not the answer back in post 2(!)?

The Transient response is covered already by the FR and does not need to be measured separately (see Fourier).

This has been discussed a gazillion times and you find many threads on this already here.
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
When have any of you, in that situation, heard an issue that is clearly related to the attack part of an instrument's sound, or anything else that can clearly be caused by a transient?
Very often, with the right setup. At least I think it has to do with transients, at least in part. It’s a startling presence of a sound source in the air, in the room in front of you. Startling is the right word, because it can really startle you for its realism. This happens mostly with small ensembles, single voices, etc., not so much with large orchestras. You can easily make out groups of instruments in an orchestra, but you don’t feel like there’s a violin there somewhere. I suppose the multiple instruments blur each other’s transients and make a more homogenous sound.

It can also happen with non-acoustic (i.e. synthesized) music. I listened to a track once (I think it was Yello), and constantly looked over my shoulder because I thought there was someone at the door. The door is on left, somewhat behind the listening chair. Sounds from behind don’t usually do that. They can be interesting effects but you can tell they’re part of the programme. But this effect was so well-crafted that it fooled me multiple times in a row. I even turned off the music to see whether it stops.

These things only come out when my system is at its peak (speakers in the right position, room treated, DSP spot on). I often experiment with different speaker positions, room treatments, Dirac filters, etc. and it is very easy to ruin this ability.

It‘s a bit like the magic that suddenly happens when you bring a telescope into perfect collimation :cool:
 
OP
Tangband

Tangband

Major Contributor
Joined
Sep 3, 2019
Messages
2,994
Likes
2,789
Location
Sweden
I find myself wondering what the issue actually is here.
Quite a bit of the debate may need modification because it considers instruments, but not that we are really listening to musicians manipulating instruments, and the sounds and timing of what the musicians do is what needs to be reproduced. It may be a matter of finer control of very small signal changes we are concerned with for that reason.

Then though, I find myself with a big "but".

Let's assume that we put a speaker in a reasonable room, with a usable front end and a sufficient amplifier, and play some vaguely well recorded music on it. When have any of you, in that situation, heard an issue that is clearly related to the attack part of an instrument's sound, or anything else that can clearly be caused by a transient? Even on "very poor" speakers, speech is usually distinct, you'll "pass the foot tapping test", you'll be able to tell what instrument is being played if it is being played solo, you can hear when the instrument starts and when it stops. Yes, we can point to "detail", but it's noted in threads here time and again that detail issues are related to frequency response and distortion.

Is not the answer back in post 2(!)?
Dont agree at all.
Bad loudspeakers make speech very indistinct, and robs the music from every sence of realism making the experience to listen to music very boring. Havent you heard a really good hifisystem ? The sound is very far from any bluetooth kitchen device.

My Eneby 20 loudspeaker in the kitchen sounds very dull compared to my Genelecs.
 

mixsit

Member
Forum Donor
Joined
Jul 20, 2019
Messages
75
Likes
23
If it is stationary, what happens to the pressure wave in the air?
My 70 year old gut tells me, the wave front passes through the space, but the space (or room) was never actually pressurized.
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
My 70 year old gut tells me, the wave front passes through the space, but the space (or room) was never actually pressurized.

You mean the rising edge travels? I agree, we can have any (steady) level in an electrical signal, but waves in an unconfined medium don’t really do DC. The pressure would just fall off and reach zero.
 

Thomas_A

Major Contributor
Forum Donor
Joined
Jun 20, 2019
Messages
3,422
Likes
2,407
Location
Sweden
Just curious, but hasn't the square wave/step response matter in traditional x-overs been dealt with in numerous threads and referred to as inaudible?
 

theREALdotnet

Major Contributor
Joined
Mar 11, 2022
Messages
1,181
Likes
2,036
Just curious, but hasn't the square wave/step response matter in traditional x-overs been dealt with in numerous threads and referred to as inaudible?

I’m sure it has. But so has the matter of stereo being silly and mono all we need (or true multi-channel), or the matter of an amplifier being state-of-the-art if it survives a week.

Kidding aside, there are listening demos which clearly show that phase distortion is ignored at your own peril, and square/step/impulse responses are simply ways of showing said distortions more easily. The thing with phase response is, sometimes accuracy matters, sometimes it doesn’t. Same with magnitude response, funnily.
 

dualazmak

Major Contributor
Forum Donor
Joined
Feb 29, 2020
Messages
2,820
Likes
2,950
Location
Ichihara City, Chiba Prefecture, Japan
It should be noted that what Tangband is talking about is not just upper FR and rise/fall time but transients 'first' wavefront that is of importance, not so much what happens after that (steady state signals).
.....
.....
A bit like this:
index.php



index.php


When it is the first wavefront that is the most important (got the impression it is) then only the amplitude of the first part on the left is important for that 'impulse' aspect.

Yes, I fully agree with you.

In January 2022, I did exactly the same for my DSP-based multichannel multi-SP-driver multi-amplifier audio setup, and I have already shared in detail on my project thread.
For the details, please visit my post here on my project thread:
WS003122 (1).JPG


WS003120 (1).JPG


WS003119.JPG


For details, please visit my post here on my project thread.
WS003329 (1).JPG

For the details, please visit my post here on my project thread:
WS003304.JPG


WS003309.JPG


WS003310.JPG

For the details, please visit my post here on my project thread:
WS003137.JPG


WS003138.JPG


WS003139.JPG


WS003140.JPG


WS003153 (2).JPG


For details, please visit my post here on my project thread.
WS003329 (2).JPG
Edit:
I was really impressed by the still-now surprisingly excellent transient behavior (kick-up/rise and fade-out/down) of 30 cm Yamaha JA-3058 woofer in heavy rigid NS-1000 sealed cabinet stimulated by 8-wave and 3-wave sine tone burst signals of 63 Hz, 125 Hz, 250 Hz, 500 Hz and even 1000 Hz, driven directly (no LCR-network) by powerful HiFi amplifier Yamaha A-S3000; I now use it in 45 Hz - 500 Hz Fq zone in my setup, though.

I believe not only the physical woofer driver design but also the sealed heavy cabinet design/rigidity and the dedicated direct-driving amplifier all together would be effectively contributing to the excellent transient behavior.

Edit:
If you would be seriously interested in the precision tone burst signals (test tones) I prepared for these measurements, simply PM me writing your wish.
 
Last edited:

Galliardist

Major Contributor
Joined
Jun 26, 2021
Messages
2,558
Likes
3,273
Location
Sydney. NSW, Australia
Very often, with the right setup. At least I think it has to do with transients, at least in part. It’s a startling presence of a sound source in the air, in the room in front of you. Startling is the right word, because it can really startle you for its realism. This happens mostly with small ensembles, single voices, etc., not so much with large orchestras. You can easily make out groups of instruments in an orchestra, but you don’t feel like there’s a violin there somewhere. I suppose the multiple instruments blur each other’s transients and make a more homogenous sound.

It can also happen with non-acoustic (i.e. synthesized) music. I listened to a track once (I think it was Yello), and constantly looked over my shoulder because I thought there was someone at the door. The door is on left, somewhat behind the listening chair. Sounds from behind don’t usually do that. They can be interesting effects but you can tell they’re part of the programme. But this effect was so well-crafted that it fooled me multiple times in a row. I even turned off the music to see whether it stops.

These things only come out when my system is at its peak (speakers in the right position, room treated, DSP spot on). I often experiment with different speaker positions, room treatments, Dirac filters, etc. and it is very easy to ruin this ability.

It‘s a bit like the magic that suddenly happens when you bring a telescope into perfect collimation :cool:
We're talking speakers here though. The speakers' particular ability doesn't change because the setup of the rest of the system isn't perfect. And I can assure you that low cost speakers from the 1980s can achieve that sort of effect on occasion.

I'm going to stay on the very controversial edge of this though. When I have heard some of these startling effects and oddities, they aren't "real", and I can be pretty sure that they are mostly not part of what was intended in the recording. Singers are supposed to be on stage, drummers normally at the back, guitars to the sides, and so on. First violins to the left, second to the right, cellos to left of centre, (maybe in front and slightly to the left or well to the left according to the orchestra's practice), and so on. When an instrument suddenly jumps to sound "realistic" and way off to the side, or the bass player "sits in my lap" (yes, I've had that appear to happen) I regard it as wrong. I tend to think of two channel stereo (not so surround, if that is what you have) as being a bit like a slightly 3D TV image. Things should be in place and I should be able to understand everything in context. Even if you have a strong central image for your vocalist, if you have a choir or operatic chorus involved, or different singers placed across the soundstage, that one sticking out becomes, well, a problem.

Special effects aside - the Yello example you give may be the genuine article.

Dont agree at all.
Bad loudspeakers make speech very indistinct, and robs the music from every sence of realism making the experience to listen to music very boring. Havent you heard a really good hifisystem ? The sound is very far from any bluetooth kitchen device.

My Eneby 20 loudspeaker in the kitchen sounds very dull compared to my Genelecs.
In the last few weeks I have listened to music:
  • on hold music on a smartphone:
  • 1950s valve radio:
  • small speakers in a large hall, so compromised sound:
  • last night at dance class, on a portable Bluetooth speaker:
  • my sister's Echo Dot (she has a decent setup as well, but her friends' seasonal radio broadcasts are on low bitrate internet and AM radio, so she listens to them on it because she wants that sound for that experience):
  • three or four decent hifi systems, including my own
So, in none of those cases, even though audio was sometimes quite badly compromised, was spoken voice unintelligible, timing of the start of instrument sounds affected (the ends were, due mainly to spaces the devices were in, as I heard it), I could tap my foot or dance to the music concerned, I could identify different individual instruments quite happily.

I'm not arguing that these devices were equivalent in overall audio quality, far from it. I'm just saying that the transient response of drive units, even older ones, were all quite capable in terms of starting and stopping, and producing what they were designed to produce according to the space they were in. Of course the hifi systems did better: they had better frequency range and response, almost certainly had better sources, they were louder (never underestimate that), Transient response, in terms of starting and stopping diaphragm movement? Hardly an issue in comparison with all of the other shortcomings.

I've reported another experience here before, where a smartphone outperformed a half-million dollar but badly set up system in a store demo room, for the really important details of an orchestral recording. While I'm not going to go as far as to say that speaker transient response is completely "solved" or anything that dumb, it's hardly the problem that bad design and setup, poor frequency response, high distortion and the other usual suspects are.
 
Top Bottom