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Cheapest Full Range 20hz - 20khz Speakers?

andreasmaaan

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Speaking of transient response and group delay, I'm interested to see the opinions fly when we talk about our first speaker with a passive radiator. Here's a Mackie rep's response about the HR824:

"...Yes the output of the passive radiator is slightly delayed from the front fired wave. It does require some time to get the mass of the radiator moving. But it also requires some time (granted not as much) to get the air moving through a port. And a port that was long enough to do what the passive radiator does would create other issues if it was even possible..."
Yes, this is an accurate statement IMO. The "issues" caused by long ports I explained in a bit of detail here. They are particularly a problem in 2-way designs. For woofers in 3-way designs and (especially) subwoofers, ports can get very long before they start causing the same kinds of problems, since the pipe resonances and standing waves within the cabinet will remain out of band until the dimensions become quite large.

The HR824 is a two-way design of course, and therefore more susceptible to the problems described.
 
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tuga

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The question, though, is whether the effects will be audible. I guess I can do two things to try to convince you. Firstly, let me refer you back to the study I talked about in post #181. Look at the group delay in the low bass for those stimuli (Group A) for which no audible difference was discerned. They are literally (way) off the chart.
I didn't download the paper since it was AES and I assumed not free.
Did they create a test identical to what I proposed, a series of quick successive notes played on a kick drum?
My reasoning, which could be incorrect, is that this would cause non-linearities that might be audible.

I understand that current knowledge invalidates my hypothesis but I am betting on the chance that current knowledge is short (for want of a better word).

Secondly, let me suggest you try this piece of software. It's a little piece of freeware that you can load any WAV file into and then play around with phase distortion, and then ABX test yourself with. If you want to emulate the phase distortion caused by a ported speaker, click "low filter" and "phase 24dB/octave", then choose your enclosure resonance Q factor (values under 0.71 are overdamped, values above 0.71 are underdamped).
No WinOS in the house unfortunately. :confused:
 

andreasmaaan

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I didn't download the paper since it was AES and I assumed not free.
Did they create a test identical to what I proposed, a series of quick successive notes played on a kick drum?
My reasoning, which could be incorrect, is that this would cause non-linearities that might be audible.
They used impulses rather than a real instrument. Similar to that 5ms audio file that I sent you. Previous studies had shown that subjects were more sensitive to phase distortion with this type of signal than with recorded music of any kind.

No WinOS in the house unfortunately. :confused:
If you'd like to send me a file of your choice, I can run it through and send you the phase-distorted copy?
 

tuga

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They used impulses rather than a real instrument. Similar to that 5ms audio file that I sent you. Previous studies had shown that subjects were more sensitive to phase distortion with this type of signal than with recorded music of any kind.
I'd be interested to learn more about those studies, or to be more precise methodology, sample size and experience of listeners, but won't bother you with that.

If you'd like to send me a file of your choice, I can run it through and send you the phase-distorted copy?
Only if it's not too much trouble.
I need to find a track that would be most fit for purpose.
Is it possible to set the tuning frequency of the port?
(does it make sense to speculate that if issues are audible then it's more likely to happen with a port tuned to 40Hz than 20Hz?)
 

andreasmaaan

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Only if it's not too much trouble.
I need to find a track that would be most fit for purpose.
Is it possible to set the tuning frequency of the port?
(does it make sense to speculate that if issues are audible then it's more likely to happen with a port tuned to 40Hz than 20Hz?)
Yeh, you can set the tuning frequency. I would set it a lot higher than even 40Hz personally, if I wanted to give myself the best shot at hearing a difference :)

But 40Hz seems pretty reasonable, so long as you choose music with some content in that frequency region.
 

Duke

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Secondly, let me suggest you try this piece of software. It's a little piece of freeware that you can load any WAV file into and then play around with phase distortion, and then ABX test yourself with. If you want to emulate the phase distortion caused by a ported speaker, click "low filter" and "phase 24dB/octave", then choose your enclosure resonance Q factor (values under 0.71 are overdamped, values above 0.71 are underdamped)...

@Duke, would you be interested in having a go with this, too? It's also possible to model the phase distortion caused by e.g. a 24dB/octave mid-tweeter crossover...
Thanks, I'll download it and take a look!
 

tuga

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Yeh, you can set the tuning frequency. I would set it a lot higher than even 40Hz personally, if I wanted to give myself the best shot at hearing a difference :)

But 40Hz seems pretty reasonable, so long as you choose music with some content in that frequency region.
Do you have any recording of Prokofiev's Romeo & Juliet Suite No. 2, Op64B?
The first 25 seconds of the first piece Montagues & Capulets might be a good choice.




Another perhaps better option might be the first 5 seconds of Ravel's Fanfare for the ballet "L'Éventail De Jeanne". Denon's recording of the ONF directed by Inbal was probably minimally mic'ed (maybe even a single stereo pair, I don't have the booklet to confirm this).

 

andreasmaaan

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Do you have any recording of Prokofiev's Romeo & Juliet Suite No. 2, Op64B?
The first 25 seconds of the first piece Montagues & Capulets might be a good choice.




Another perhaps better option might be the first 5 seconds of Ravel's Fanfare for the ballet "L'Éventail De Jeanne". Denon's recording of the ONF directed by Inbal was probably minimally mic'ed (maybe even a single stereo pair, I don't have the booklet to confirm this).

Yep, they look like good candidates. Would you be willing to send me say 30 second excerpts? (FWIW I think this would come under the fair use (educational purposes) copyright exception.)
 

tuga

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Yep, they look like good candidates. Would you be willing to send me say 30 second excerpts? (FWIW I think this would come under the fair use (educational purposes) copyright exception.)
I am now thinking that though my choices might higlight the issue I mentioned (quick succession of percussive low frequency notes) they may not be the best choices for assessing (generic) phase distortion.

I wonder what kind of musical programme you or @Duke would suggest that would better highlight phase distortion and at what frequency?
Harpsichord?
 

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andreasmaaan

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I am now thinking that though my choices might higlight the issue I mentioned (quick succession of percussive of low frequency notes) they may not be the best choices for assessing (generic) phase distortion.

I wonder what kind of musical programme you or @Duke would suggest that would better highlight phase distortion and at what frequency?
Harpsichord?
Yeh exactly I reckon. I'd think your best shot would actually involve midrange phase distortion and a signal that consists of (perhaps counter-intuitively) long sustained notes and a lot of harmonics. Harpsichord, synth, saxophone... opera maybe?
 

infinitesymphony

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Had some fun with the phase audibility program, but the lag between ABX was a definite tell. Some of the noise generators had less lag and that made them more difficult to tell apart.
 

tuga

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Yeh exactly I reckon. I'd think your best shot would actually involve midrange phase distortion and a signal that consists of (perhaps counter-intuitively) long sustained notes and a lot of harmonics. Harpsichord, synth, saxophone... opera maybe?
Not something that I listen to often but perhaps it'll work. The snippet is too big. It'll have to wait for tomorrow.
 

andreasmaaan

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Not something that I listen to often but perhaps it'll work. The snippet is too big. It'll have to wait for tomorrow.
This is really strange, but the program just doesn't seem to like the Ravel snippet you sent me!

So I did it manually, by creating an FIR filter with group delay corresponding to:
  • Ported box, under-damped alignment, F3 of 40Hz
  • LR4 crossover at 1kHz
Actually, I think it's better this way, as I trust RePhase more than I trust that piece of software to do exactly what it says it will and to not introduce audible amplitude response errors.

So anyway, I created two files. I ran both through the Windows mixer, but only one is phase-distorted. I've uploaded the two files (one distorted, one undistorted) to this google drive folder (they were too large to upload directly to ASR). I also made the exports 24 bit, just to make sure no audible noise could be introduced, e.g. by dithering.

Would you like me to tell you which is which?
 

andreasmaaan

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@dasdoing I also (finally) uploaded the files you sent me to do this with.

Same filters as Tuga's files:
  • Ported box, under-damped alignment, F3 of 40Hz
  • LR4 crossover at 1kHz
And in the same folder.
 

Shazb0t

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This is really strange, but the program just doesn't seem to like the Ravel snippet you sent me!

So I did it manually, by creating an FIR filter with group delay corresponding to:
  • Ported box, under-damped alignment, F3 of 40Hz
  • LR4 crossover at 1kHz
Actually, I think it's better this way, as I trust RePhase more than I trust that piece of software to do exactly what it says it will and to not introduce audible amplitude response errors.

So anyway, I created two files. I ran both through the Windows mixer, but only one is phase-distorted. I've uploaded the two files (one distorted, one undistorted) to this google drive folder (they were too large to upload directly to ASR). I also made the exports 24 bit, just to make sure no audible noise could be introduced, e.g. by dithering.

Would you like me to tell you which is which?
 

infinitesymphony

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My vote's for Panotsi 1 and Ravel 2 being "the same," whether that's unshifted or shifted. I would guess unshifted. You know, if there's actually a difference between any of the files at all. I spent 5 minutes listening on a pair of $9 headphones, so don't blame me if I'm wrong. :cool:
 

Duke

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This is really strange, but the program just doesn't seem to like the Ravel snippet you sent me!

So I did it manually, by creating an FIR filter with group delay corresponding to:
  • Ported box, under-damped alignment, F3 of 40Hz
  • LR4 crossover at 1kHz
Actually, I think it's better this way, as I trust RePhase more than I trust that piece of software to do exactly what it says it will and to not introduce audible amplitude response errors.

So anyway, I created two files. I ran both through the Windows mixer, but only one is phase-distorted. I've uploaded the two files (one distorted, one undistorted) to this google drive folder (they were too large to upload directly to ASR). I also made the exports 24 bit, just to make sure no audible noise could be introduced, e.g. by dithering.

Would you like me to tell you which is which?
Thank you!!

My call is that Pantosi 1 and Ravel 2 are UNSHIFTED, and Pantosi 2 and Ravel 1 are phase SHIFTED.

Listened to each track maybe 3 or 4 times on my (no-name) cheap earbuds.

Embarrass me, mock me, hurl insults in my general direction if I'm wrong. I'll deserve it.
 
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infinitesymphony

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Thank you!!

My call is that Pantosi 1 and Ravel 2 are UNSHIFTED, and Pantosi 2 and Ravel 1 are phase SHIFTED.

Listened to each track maybe 3 or 4 times on my (no-name) cheap earbuds.
Well, we're both in agreement, so we're going to be right or wrong together. Or I poisoned the well by being the first to post. Somebody with golden ears please use some higher fidelity equipment than we did for contrast. :D
 
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