Jeff wrote:

Orava wrote:

 

DMacri wrote:

Orava wrote:

I think Thiel, Vandersteen, and DALI and a few others had similar design goals/attempts.

Not to mention the original Dahlquist DQ-10, phase and time alignment was a forte of this 5 way design. And it did have a fairly small sweet spot, but man, the sound in that sweet spot was amazing. Sounded best if you did the mirror image and cap mods. I used to sell these back in college. 

R

 

Ah, maybe they didn´t have distributor here at that time... or they were in price category I didn´t dare to look.

They were mainly a product of the mid to late 70's. They looked like Quad electrostats but with cloth grills rather than metal, mainly since John Dahlquist loved Quads. A partner in the company was THE Saul Marantz. They were not efficient, really needed a good high current amp, and we're bass shy, which is why they developed a good subwoofer for them, but the imaging and smoothness were addictive. The midrange driver was a dipole, a conventional cone driver free air mounted with a felt pad over the back. Very placement critical, more so than the MS150, as you had the rear back wave to contend with, like all dipoles. 

Back then, there were two stereo stores on the same college town street, we sold Dahlquist, ADS, Polk, Harman Kardon, and a bunch of other high end stuff, and the other dealer sold Klipsch and, ta da, B&O!  They went out of business ao we moved into their storefront, then we went under, mainly due to mismanagement. The owner would trade equipment out the back door for coke, which doesn't pay the bills. 

You mean these?

http://www.ebay.de/itm/Vintage-Highend-Dahlquist-DQ-10-Marantz-Design-Boxen-Made-in-the-USA-1976-/290774629423?pt=DE_Lautsprecher_Martin&hash=item43b384bc2f

Frankly, then look like "home made" 😕

Jeff wrote:

They were mainly a product of the mid to late 70's. They looked like Quad electrostats but with cloth grills rather than metal, mainly since John Dahlquist loved Quads. A partner in the company was THE Saul Marantz. They were not efficient, really needed a good high current amp, and we're bass shy, which is why they developed a good subwoofer for them, but the imaging and smoothness were addictive. The midrange driver was a dipole, a conventional cone driver free air mounted with a felt pad over the back. Very placement critical, more so than the MS150, as you had the rear back wave to contend with, like all dipoles. 

Back then, there were two stereo stores on the same college town street, we sold Dahlquist, ADS, Polk, Harman Kardon, and a bunch of other high end stuff, and the other dealer sold Klipsch and, ta da, B&O!  They went out of business ao we moved into their storefront, then we went under, mainly due to mismanagement. The owner would trade equipment out the back door for coke, which doesn't pay the bills. 

In about 1987 I listened to a pair of Dahlquist DQ-10s driven by a Phase Linear 400.  Probably the best sounding reproduction of music I've heard ever.  And this was outside, on a concrete slab patio.

Source material?  Original Sony Discman plugged directly into the Phase Linear power amp.

Bought the Phase Linear but did not have the cash for the DQ-10s.

Regretted to this day.

Yup, that's them! All the upper drivers are on individual baffles the size and distance from the listener being determined by the time alignment and freq range covered. Once heard a setup with double DQ10's, stacked, with two subs, one for each side. Very impressive.

Maybe interesting for those taking part in this thread (if you can read French):

https://docs.google.com/file/d/0BwTS40IaQa16ckdKOVEtQ2xSOUNoR2JhOGV4TVFjdw/edit?pli=1

That talks about the technical concept of the Beovox Uniphase 1st series. The graphs with the square wave response at 0, 15 and 30 degrees on the horizontal plane have been expecially useful for me - it is clear that the MS 150 should stay parallel to the back wall in order to achieve a correct frequency response at the listening point. I'm still experimenting with the position on the vertical axis... :)

Excellent read!

Thank you!

DMacri wrote:

I know there is a good write up on this somewhere, but the Uniphase design matched the drivers in frequency and time domains. The angles of the baffles provided some time alignment and the crossovers where low order. This also meant the positioning of the speakers was critical so height and angles really matter. Although a pain to set up properly, they will offer excellent imaging and soundstage depth. More realism than typical speakers.

Could this be reason for poor-looking test measurements? If they have standard setup for it, microphone is just in wrong spot for this kind of speaker.

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So, I had fun translating the Finnish details... :D (With Google...)

measurements
Investment kajunta in a room on the floor in their own pedestal, 5 cm from the wall.
The calculated efficiency: 0.43%, the corresponding impedance: 8 ohm.
Crack Measured maximum voltage: 4.9 V
The acoustic power level of 1 V voltage of 87.5 dB
Speaker was measured without the front grill.
Free field measurement, the measuring microphone was the tweeter height.

The upper graph ist the free field frequency response, the second the power response. "Vas." is left and "Oik" is right.

I think I can say that the graphs don't match what I am hearing, since with a slow frequency sweep I should be able those points at -20 dB - and I don't...

mscili wrote:

So, I had fun translating the Finnish details... :D (With Google...)

measurements
Investment kajunta in a room on the floor in their own pedestal, 5 cm from the wall.
The calculated efficiency: 0.43%, the corresponding impedance: 8 ohm.
Crack Measured maximum voltage: 4.9 V
The acoustic power level of 1 V voltage of 87.5 dB
Speaker was measured without the front grill.
Free field measurement, the measuring microphone was the tweeter height.

The upper graph ist the free field frequency response, the second the power response. "Vas." is left and "Oik" is right.

I think I can say that the graphs don't match what I am hearing, since with a slow frequency sweep I should be able those points at -20 dB - and I don't...

Hum, near... I dont quite know myself these terms in english, but...

"Investment kajunta in room" = Placement in echoroom
"Pedestal"(?) = Stand
"Crack" = distortion (crack, really...)

I guess that if the mic is at tweeter level, it is too high. Tweeter is positioned slightly downwards, isn't it? So optimal listening position is down from tweeter high, if the speaker is on upright level. Anyway, situation in normal listening room might be complety different.
Whats more intresting is that if you are 30 deg offline in either side, there is notch at 5kHz. Tells about critical positioning of these speakers, meaning if in right position 20dB notch on 900Hz might be absent?

Orava wrote:

I guess that if the mic is at tweeter level, it is too high. Tweeter is positioned slightly downwards, isn't it? So optimal listening position is down from tweeter high, if the speaker is on upright level. Anyway, situation in normal listening room might be complety different.

This is difficult to say, since the tweeter is clearly advanced compared to the other drivers, but it is very difficult to tell if it has any direction upwards or downwards. You can also adjust the position of the loudspeakers by moving a specific part of the stand, having them more or less "upwards"... What I notice is that there is clearly a precise listening height were the imaging and the tonal balance get better. The soundstage gets bigger (expecially vertically) and the intrument get a more "real" and precise quality. Go lower, and everything gets a bit confused; go higher, and you'll get a feeling of more clarity, but loosing "reality" and balance.

Whats more intresting is that if you are 30 deg offline in either side, there is notch at 5kHz. Tells about critical positioning of these speakers, meaning if in right position 20dB notch on 900Hz might be absent?

I don't know, but in my listening position (30 degrees, 1,5 m distance) there is definitely no notch at 5 kHz, nor around 1000 Hz. I'm pretty sure I would be able to hear that. The balance and the imaging get much better if you listen off-axix by 30 degrees... I think that's the way these loudspeakers are supposed to be placed...

I was under the impression that when the speakers were properly situated on the stands, the tweeter part of the cabinet was vertical, and the woofer/mids were aligned forward of the tweeter, with the drivers tilted up. That would be in line with the standard approach of time alignment where the lighter, fastest responding drivers are mounted farther from the listeners ears with the heavier driver closer. Especially with low order, minimum phase crossovers.

My old DCM Time Windows mounted the woofer above the tweeter, and at ear level, so the tweeters were farther from the listeners ear, and displayed excellent time domain response. I've never opened them to see what the crossover topology is like.