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Perlisten speakers

hardisj

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However, as to the actual point, I had done some experiments with reticulated foam in the ports of subwoofers to see if it could reduce port noise. I looked at two things, a reduction in port resonances, a reduction in port chuffing. I got the idea from Earl Geddes and he directed me on how to conduct the tests. I did all the tests with a low noise calibrated measurement microphone and nearfield measurement of the port itself. Ultimately, I didn't find it worked very well for either. Port resonances were only marginally reduced, not enough to matter in many cases. Good port design in the first place turned out to be more important. It also didn't help port chuffing. In fact, best I could tell from this crude method of measuring chuffing, it made it worse.

What I've continuously found is that the port is hardly ever the real culprit; it's simply that the internal resonances of the enclosure are leaking out of the port. I've tested this numerous times (sometimes sharing the data, sometimes not) by stuffing the port and re-measuring the speaker to see if a mid-to-upper-midrange resonance remains in place and the majority of the time it does. As reviewers/viewers of the data, we typically jump to "port noise" because of the high amount of energy escaping through the port but it's almost always enclosure resonance(s) that are the real culprit.
 

Godataloss

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What it did do, which I did like, was lower the Q of the tuning. This allowed a small extension of the LF response at the expense of a bit of output around tuning. similar to the QB3 alignment mentioned above. I found that if I placed a plug of 30ppi reticulated foam in the port that covered 2/3 or more of the length, I could closely mimic the Qb3 alignment. However, as noted, it seemed to make port chuffing issues worse.
I believe this is why Goodmans did it as well. I had a pair of the Triaxiom 15 inch coaxials. The cabinets spec'd an ARU- Acoustic Resonating Unit- felt and mesh in a wood panel about 10 inches square. Link to a discussion on AK if you're interested. Needless to say they are as rare as hen's teeth in the US and I just sold the drivers on Ebay and sent them back home over the pond for an embarrassing profit.
 

Matthew J Poes

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What I've continuously found is that the port is hardly ever the real culprit; it's simply that the internal resonances of the enclosure are leaking out of the port. I've tested this numerous times (sometimes sharing the data, sometimes not) by stuffing the port and re-measuring the speaker to see if a mid-to-upper-midrange resonance remains in place and the majority of the time it does. As reviewers/viewers of the data, we typically jump to "port noise" because of the high amount of energy escaping through the port but it's almost always enclosure resonance(s) that are the real culprit.
That could very well be right. In my subwoofer examples, resonances would be surprising, but in many of the speakers you have reviewed, I could see that. In my subwoofers that I was referring to, the enclosures were CNCed for me using that interlocking matrix style bracing and all cabinet sizes were made by laminating MDF together in an interlocking manner, including interlocking corner profiles (They snapped together). Thickness on the front baffle was 3" and sides were 1.5" thick. It would be surprising if the problem was enclosure resonances. I had a fairly similar sealed and ported version, and then because of problems with the ported one I made the first time, I had them make a new one with a much bigger port. Same basic design, just the port area (and thus length too) were increased substantially. When I did that, I got a honking resonance. When I looked at my data on the sub measured outside, there was a clear sign of a resonance that was evident but higher in frequency and lower in level that seemed to have shifted down. I recall doing a calculation and finding that resonance matched the theoretical pipe resonance for the port too.

I had thought that reticulated foam would help but it didn't do anything.

However, blocking it totally did.

Most speakers are not built like that. Those enclosures weighed around 200lbs each with no drivers or insulation. I think the larger one was like 275. They were all for a 12" driver with around 3 cubic feet of internal volume, so we are talking a modest sized box.
 

Matias

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FYI Perlisten S7t is in December 21 edition of Stereophile. @Kal Rubinson reviewed it and liked it very much. Horizontal dispersion measurements is quite nice.
 

Spocko

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FYI Perlisten S7t is in December 21 edition of Stereophile. @Kal Rubinson reviewed it and liked it very much. Horizontal dispersion measurements is quite nice.
Didn't take long for Perlisten to post Kal's review!

I'd say the wisdom of the crowds have spoken - the beam forming array is genius and I look forward to seeing if the more affordable Perlisten R-series share these class leading directivity characteristics (for passive speakers).
 
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Matias

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Impressive.

print.jpg


And of course the datasheet.

datasheet.jpg
 
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Kal Rubinson

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That narrow dispersion vertical directivity blows my mind - seriously, this was clearly designed to avoid ceiling bounce in a home theater environment.
or even with a stereo system. :D
 

Spocko

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or even with a stereo system. :D
So I need clarification or just additional insights here (for the stereo listener). In home theater you have discrete overhead speakers that would not take kindly to bed level speaker cancellations/interference from the ceiling bounce, but for 2 channel stereo listening, do ceiling bounces offer a vertical soundstage in the same way that first reflections provide a wider horizontal soundstage (which is what Dr. Toole prefers)?
 

Jdunk54nl

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This is interesting discussion on the narrow vertical stuff and praise of how narrow and well controlled it is.
It is one of the biggest criticisms of the @Dennis Murphy and his Philharmonic BMR stuff and other RAAL tweeter speakers. Yet here it is praised.
I know the BMR stuff isn't quite as controlled as this, but both seem fairly narrow vertical.

Can someone explain this? I am truly interested in what I am missing and wanting to learn.


Here is the S4b (Erins Audio Corner)
Perlisten%20S4b%20Vertical%20Contour%20Plot%20%28Normalized%29.png




Here is the BMR (Erin's Audio Corner)
Philharmonic%20BMR_Vertical_Spectrogram_Norm_Full.png


Here is the s7t (Audioholics)
image_preview2
 
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Kal Rubinson

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So I need clarification or just additional insights here (for the stereo listener). In home theater you have discrete overhead speakers that would not take kindly to bed level speaker cancellations/interference from the ceiling bounce, but for 2 channel stereo listening, do ceiling bounces offer a vertical soundstage in the same way that first reflections provide a wider horizontal soundstage (which is what Dr. Toole prefers)?
I suspect they affect our perception of a vertical soundstage but I have only my own anecdotal experience to think so.
 

JRS

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I suspect they affect our perception of a vertical soundstage but I have only my own anecdotal experience to think so.
I vaguely recall a paper by Olive saying that vertical reflections had more of an impact on timbre than perceived spaciousness, and that floor bounce was used to calculate distance from source. (Which sort of makes sense given we were born on the savannah).
 

pozz

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This is interesting discussion on the narrow vertical stuff and praise of how narrow and well controlled it is.
It is one of the biggest criticisms of the @Dennis Murphy and his Philharmonic BMR stuff and other RAAL tweeter speakers. Yet here it is praised.
I know the BMR stuff isn't quite as controlled as this, but both seem fairly narrow vertical.

Can someone explain this? I am truly interested in what I am missing and wanting to learn.


Here is the S4b (Erins Audio Corner)
Perlisten%20S4b%20Vertical%20Contour%20Plot%20%28Normalized%29.png




Here is the BMR (Erin's Audio Corner)
Philharmonic%20BMR_Vertical_Spectrogram_Norm_Full.png


Here is the s7t (Audioholics)
image
(The Audioholics plot you posted is for horizontal response.) I think the main thing to note is that the vertical directivity is very controlled in Perlisten speakers. Nearly the whole of the range consistently down vs. dips, lobing and beaming with more conventional speakers.
 

Matias

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Matias

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(The Audioholics plot you posted is for horizontal response.) I think the main thing to note is that the vertical directivity is very controlled in Perlisten speakers. Nearly the whole of the range consistently down vs. dips, lobing and beaming with more conventional speakers.
Vertical dispersion also has been controlled in previous Dynaudio speakers by having calculated cancelations between both tweeters, and currently with their waveguide too.

images
 

bo_knows

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Vertical dispersion also has been controlled in previous Dynaudio speakers by having calculated cancelations between both tweeters, and currently with their waveguide too.

images
Dynaudio DDC. If I'm not wrong, was introduced with Evidence and Temptation speakers.
 

Inner Space

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I vaguely recall a paper by Olive saying ... that floor bounce was used to calculate distance from source. (Which sort of makes sense given we were born on the savannah).
I have read that too. Imagining an evolutionary inheritance there is lazy thinking, surely. The savannah wasn't hard, flat or reflective. We've lived with flat reflective floors for what, a couple hundred years? Far too recent to have an evolutionary influence.
 

pozz

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Vertical dispersion also has been controlled in previous Dynaudio speakers by having calculated cancelations between both tweeters, and currently with their waveguide too.

images
Do we have measurements of that model? Would be nice to compare.
 
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