Free measuring and testing services

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fdjslkgh

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Re: Free measuring and testing services
« Reply #20 on: 5 Apr 2018, 02:03 pm »
Danny, I've got a pair of Acoustic Research AR M1s (the $300 speakers that Mark Levinson used to use to demonstrate his Cello electronics) that have a simple first-order (cap and resistor) crossover on the tweeter and nothing on the woofer. With your help, I've already upgraded the cap to a Sonicap, do you think there's any value in going further with these? I'm not averse to shipping them to you, and they were generally regarded as punching above their weight class, but I don't know how quickly you think we'd run into diminishing returns.

Danny Richie

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Re: Free measuring and testing services
« Reply #21 on: 6 Apr 2018, 07:48 pm »
Danny, I've got a pair of Acoustic Research AR M1s (the $300 speakers that Mark Levinson used to use to demonstrate his Cello electronics) that have a simple first-order (cap and resistor) crossover on the tweeter and nothing on the woofer. With your help, I've already upgraded the cap to a Sonicap, do you think there's any value in going further with these? I'm not averse to shipping them to you, and they were generally regarded as punching above their weight class, but I don't know how quickly you think we'd run into diminishing returns.

I have no doubt that I can do a lot with them and take them up a level or two in performance. With shipping each way plus crossover parts you'd spend $250 to $300 pretty easily.

You're call...

fdjslkgh

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Re: Free measuring and testing services
« Reply #22 on: 9 Apr 2018, 04:55 pm »
I need to replace the dustcaps, as they seem to have degraded over time, and then I'll give them another listen and make a decision. There are so few sealed 2 way designs out there that I'm somewhat inclined to really blow these out of the water and have something truly unique. Since I bought them for $30 off Craigslist it would't be the end of the world to pay $300 total for something really special-sounding.

danvprod

Re: Free measuring and testing services
« Reply #23 on: 24 Apr 2018, 09:17 pm »
These ones would be fun to have your services performance on. Plus they are already wired to have an external crossover; a tweaker's dream.







Tweeter is scan-speak D2008/8512-00 3/4" Textile Dome and woofer is 5 1/2" Vifa woofer. TL enclosure tuned to ~35 Hz or so.

maty

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Re: Free measuring and testing services
« Reply #24 on: 1 Jun 2018, 09:18 am »
I had no plans to upload more images of crossovers but I could not resist seeing them on expensive Danish speakers. $3,299 / €2,599 / £1,999

Dali Opticon 8 crossover

http://www.diyaudio.com/forums/multi-way/307551-dali-opticon-8-crossovers-upgrade-help.html

Optimized by me:

[Scheme] http://maty.galeon.com/WP-imagenes/hard/Dali-Opticon-8-crossover-scheme.jpg



Danny Richie

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Re: Free measuring and testing services
« Reply #25 on: 1 Jun 2018, 12:36 pm »
Quote
These ones would be fun to have your services performance on. Plus they are already wired to have an external crossover; a tweaker's dream.

I'm upgraded quite a few of those Sililoquy's over the years. I think three different models. Some of them measured pretty rough.

Danny Richie

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Re: Free measuring and testing services
« Reply #26 on: 1 Jun 2018, 12:37 pm »
Matty, you sure have a way of finding the ones that look embarrassing inside.

maty

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Re: Free measuring and testing services
« Reply #27 on: 3 Feb 2019, 08:04 pm »
Maty, you sure have a way of finding the ones that look embarrassing inside.

KEF Q750, again.

[German] https://www.hifitest.de/test/lautsprecher_surround/kef-q750_atmos-set_15812

-> https://www.hifitest.de/test/bildergalerie/lautsprecher_surround/kef-q750_atmos-set_15812/11

[Big IMG] https://www.hifitest.de/images/testbilder/big/kef-q750-atmos-set-lautsprecher-surround-47582.jpg

[Big IMG] https://www.hifitest.de/images/testbilder/big/kef-q750-atmos-set-lautsprecher-surround-47583.jpg


Hans Wetzel wrote:

https://www.soundstageaccess.com/index.php/equipment-reviews/856-kef-q750-loudspeakers

Quote
Conclusion

KEF’s Q750 is a superb loudspeaker. It’s one of the most neutral transducers I’ve ever heard, and for the money offers staggeringly transparent sound. I fed it a steady diet of male and female singer-songwriters, and was always satisfied with the authenticity of what I heard. It’s not exactly a looker, but it’s well engineered, and sounds far more expensive than its price suggests. If I had $1500 to spend on speakers, this is what I’d buy. I’m not sure I can pay KEF’s Q750 a higher compliment.

If you do not consider the valley at 1.2 khz, I say.

I hope that a crossover redesign will solve it. What do you think?

Danny Richie

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Re: Free measuring and testing services
« Reply #28 on: 4 Feb 2019, 04:04 am »
I'm sure there is a lot that can be done with those in a number of areas.

Send a pair over and I'll let you know.

maty

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Re: Free measuring and testing services
« Reply #29 on: 4 Feb 2019, 07:23 am »
Well, you know, I live in Tarragona (Spain, EU).

Every time I have more clear that we can not trust reviews where there are no measurements. And with the other audio hardware too.

They need more mass at the furniture as mine little KEF Q100 (it was a substantial improvement) of my second audio system.

maty

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Re: Free measuring and testing services
« Reply #30 on: 4 Feb 2019, 07:32 am »
Just now I have send an e-mail to Hans Wetzel, with this link.

maty

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Re: Free measuring and testing services
« Reply #31 on: 4 Feb 2019, 02:52 pm »
Hans has confirmed and will respond in the coming days in SoundStage! Access. I have told him that I think that small valley is intentional, looking for a frequency response in soft "V".

Maybe the answer will be here:

https://www.soundstageaccess.com/index.php/feedback

Btw, SoundStage! Access | SoundStageAccess.com (GoodSound.com) - KEF: Q350, Q750, or R500?

Quote
Regarding  your question about the R500, you might have noted that I compared the  Q750 to the larger R700 in my review. If the R500 is priced similarly to  the Q750 in Sweden, I would spring for the R500 every day of the week.  While the R500 won’t be dramatically more resolving than your Q350, you  should still hear more low-level detail through the R-series model.  Furthermore, the R500 is a true three-way design, which should produce  deeper and more robust bass. Finally, the R500 is, to my eyes, a far  better-looking speaker than any Q model, with a more solid and inert  cabinet. The cumulative improvements over your Q350 should be  significant. . . . Hans Wetzel

Danny Richie

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Re: Free measuring and testing services
« Reply #32 on: 4 Feb 2019, 03:54 pm »
Hans has confirmed and will respond in the coming days in SoundStage! Access. I have told him that I think that small valley is intentional, looking for a frequency response in soft "V".

Maybe the answer will be here:

https://www.soundstageaccess.com/index.php/feedback

Btw, SoundStage! Access | SoundStageAccess.com (GoodSound.com) - KEF: Q350, Q750, or R500?

It could be intentional. There could have been some break up or stored energy there being suppressed, or there could be a peak in the horizontal or vertical off axis that is being compensated for.

I'd be more concerned about the quality of the crossover parts, wiring, binding posts, and cabinet resonances.

maty

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Re: Free measuring and testing services
« Reply #33 on: 4 Feb 2019, 05:29 pm »
Maybe you are right. Why?

The old KEF Q900

https://www.stereophile.com/content/kef-q900-loudspeaker-measurements





but the coaxial is 8" and not 5.25". The good KEF coaxial is the 5.25", not the 6.5" or 8".

https://www.stereophile.com/content/kef-q900-loudspeaker-specifications

Quote
Description: Two-and-a-half-way floorstanding loudspeaker.

Drive-units (all aluminum): Uni-Q (coaxial) with 1.5" vented dome tweeter and 8" midrange unit, 8" woofer, two 8" passive radiators.

Crossover frequency: 1.8kHz. Frequency response: 32Hz–40kHz, ±3dB. Impedance: 8 ohms. Sensitivity: 91dB/2.83V/m. Maximum output: 114dB. Amplification: 15–200W.

Every time I have more clear that the best thing is a good pair of monitors with the most flat response and one or two subwoofers (with adjustable phase). As long as they leave you at home ...

And, if the room is equalized, only f < 200 Hz.

maty

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Re: Free measuring and testing services
« Reply #34 on: 18 Feb 2019, 09:59 am »
Hans Wetzel answered:

KEF Q750: Not So Neutral?

https://www.soundstageaccess.com/index.php/feedback/951-kef-q750-not-so-neutral

[ To Hans Wetzel,

Hi from Tarragona, Spain. You wrote [in your KEF Q750 review]: “KEF’s Q750 is a superb loudspeaker. It’s one of the most neutral transducers I’ve ever heard, and for the money offers staggeringly transparent sound” [emphasis added]. But [per the measurements from www.hifitest.de‘s review, here and here], I can see a valley at 1.2kHz. I have commented about this issue in GR Research, and in DIYAudio, too. I think it is intentional, [with KEF] looking for a soft “V” response.

Maty
Spain ]

Quote
The measurements you link to do, indeed, note a roughly -3dB dip around 1.2kHz. Since you seem to be measurement-oriented, it’s worth exploring what we’re looking at. Let’s focus on the frequency-response graph. Are these measurements taken in-room, or in an anechoic chamber? Are the three curves on-axis, 15 degrees off-axis, and 30 degrees off-axis, or something else? Was it measured at 1m, 2m, or some other distance? Without any offered methodology to accompany the graph, you’re extrapolating an awful lot from three curves. That is one very narrow snapshot that is certainly better than nothing, but doesn’t offer anywhere near a complete picture of how the Q750 might sound in your average room.

Take a look at some of our measurements on www.speakermeasurements.com, which we perform in an anechoic chamber at Canada’s National Research Council, where some of the early hi-fi pioneers did their acoustic research, including Dr. Floyd Toole (of Harman International), who quite literally wrote the book on modern loudspeaker design (see below). I’ll point you to the measurements of Revel’s Performa3 F206 loudspeaker. Numerous writers on our staff agree that the Revel (which is a division of the aforementioned Harman International) F206 is the most neutral loudspeaker at its $3500 USD price point, and its measurements are about as “textbook” as you can get for that kind of money, as evidenced by the “Listening Window,” which averages five measurements into one neat plot that is both commendably smooth and flat, with a 2-3dB tilt from left to right. There is nothing amiss between 1kHz-1.5kHz. Chart A, however, which includes on-axis, 15-degree off-axis, and 30-degree off-axis curves, shows a “valley” centered at around 1.2kHz–1.3kHz; surely not neutral!

Hi-fi measurements, like everything else in life, must be placed in context. If you were to only hear direct sound from the Revel, then a deviation like that “valley” would surely be problematic. But we don’t hear like that. What our ears hear is a combination of direct sound from the speaker drivers, along with a variety of reflections that arrive at our ears at slightly different times, which our mind interpolates into something recognizable. The takeaway is that on-axis and near-on-axis measurements like the ones you mentioned in your e-mail only paint part of the picture and have the potential to be misleading if taken in isolation. I’d encourage you to take a look at some of our other measurements, which includes several KEF models. I’ll note that the Q750 is a two-and-a-half-way design that uses passive radiators in lieu of a bass-reflex port (or two). These kind of fundamental design choices may well have contributed to idiosyncrasies in the Q750’s frequency response curve that wouldn’t appear in a two-way or three-way bass-reflex design.

We try to measure as many speakers as we can, but with writers all over North America, shipping large speakers often proves expensive and impractical, so it’s not always possible. Just so you know, I actually wanted the Q750 measured, but we couldn’t make it work logistically -- sorry about that.

To answer your question above in a terribly longwinded fashion, yes, I think KEF purposely designed the Q750 to have the “valley” around 1.2kHz in its on-axis and near-off-axis frequency response curves. I am confident, however, that KEF did not intend for that to be audible, in-room, at the listening position. I suspect that if we were to run our usual battery of measurements on the Q750, the “Listening Window” plot would bear that out, and also confirm my subjective listening impressions.

I recommend Dr. Floyd Toole’s book, Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms. I think you’ll find it highly educational. . . . Hans Wetzel