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#11 | |
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diyAudio Member
Join Date: Nov 2008
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I'd like to answer, but not sure as you've recently made an attack on my integrity and implied my work is suspect. I'm no longer sure of your agenda. I did offer a fair amount of help recently in setting up an home-built isolation chambers. I get the feeling I'm being pushed into another sand-trap. Mark. Last edited by markaudio; 19th April 2012 at 08:11 AM. |
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#12 |
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diyAudio Member
Join Date: Nov 2008
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Hi Chris,
Yes, the data is RAW. Periodically, issues of interpretation come up and I too often get hit. My time gets eaten up having to repeat all this stuff. No wonder most makers do the smoothing, narrow the scales on the graphs and don't talk to end-users. Here's an example of Bob Brine's measurements of his T7 box (uses Alpair 7). Bob does excellent work, looking at his data, it appears to be RAW - wide scale presentation. Take a look at the pic and you'll see my observation on the wide variance generated by the set-up in the higher range. The variance is due to the set-up, Not the driver. There's no way an Alpair 7's power-train can mechanically drop 29dB at 12-kHz output with only a 5 degree change in the off axis position. Its an typical indication of the real challenges that exist every time we all attempt to measure drivers and systems. Overall, Bob's measurements are very good. I recommend his work to anyone wishing to buy a system or a design; And other similar audio guys who make such efforts. His frequency results pretty much correspond to my driver measurements which is very encouraging. I believe Bob, yourself, me and other experienced audio guys understand the challenges in obtaining repeatable measurements and recognise there will be variation between tests. And therein is the problem. If all makers published wide scale RAW - FULL RANGE (note "full range") frequency measurements, you'd see similar types of results as those of CHS and Alpair 12P. But then the bigger problem arises, that a few Diyers that don't understand to difference between the driver's actual net emittance and the point selection measurement generated by test software, make criticisms of said drivers, hence most makers won't take the commercial risk. I've done my best to explain these issues many times, maybe I'll have to give up and follow the other makers, go back to presenting smoother data that the majority of Diyer's are happy to use. Cheers Mark. Last edited by markaudio; 19th April 2012 at 12:56 PM. |
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#13 | |
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diyAudio Member
Join Date: Jun 2011
Location: Copenhagen
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Quote:
I agree with you about the Alpair 7.3 vs the CHR-70.3. I would say that the sound of the two drivers is much more similar than the price difference suggests. In an A/B test it really wasn't easy for me to tell the difference between the two. IMO both drivers sound just excellent, but if I should comment on the differences I would say that the Alpairs sound a bit more neutral while the CHR-70s are more forward. Mind you, the test I did was by no means scientific. I simply listened to each of the drivers over a period of time using the same test enclosure (4 litre sealed and stuffed with an active LR4 at 250Hz and bass support – A so-called FAST I suppose). Since I really enjoyed the CHR-70, I'm interested in knowing more about the CHS-70. @Mark, I would really appreciate if you would tell more about the CHS-70 from a technical perspective? And also, will this driver be sold in China only or do you plan to expand the distribution to Europe and the US in the future? Thanks, Soren |
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#14 | |
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diyAudio Member
Join Date: Nov 2008
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Quote:
Read your impressions re the CHR-70 and Alpair 7 Gen. 3's with interest. The neutrality of the Alpair 7 is the key. Its suspensions, coil and cone are more advanced than the CHR's. Interestingly, some have said to me that the latest CHR-70 is a bit too "hot" at the top-end (their expression) but that's a useful comment as its indicative of this new driver's extended range. The CHS is a step behind the latest CHR. Its frame, coil and other parts of its power-train are lower grade, but this driver still out-performs the Gen. 2 CHR. The CHS is an OEM and custom driver for the China market. There's no plans at this stage to introduce it to other regions. Thanks Mark. |
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#15 | |
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diyAudio Member
Join Date: Jun 2011
Location: Copenhagen
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Quote:
Perhaps I could persuade you to consider black as an additional colour option for the CHR-70 Gen. 4?
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#16 | |
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diyAudio Member
Join Date: Nov 2008
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Quote:
I'm with you on this, the black cones look really good. I'd like to make a CHR 70 - Gen. 3 with a black cone. I made the BB4-AL for Europe (black coned CHR-70 Gen.2 with a slight tweak) but it didn't catch on. I'm not sure if this was down to branding or promotional support issues, rather than colour. If you and other members support this idea, contact Daniel at Lautsprecher, request the black colour. Daniel Gattig vom Lautsprechershop LT: daniel@lautsprechershop.de Cheers Mark. |
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#17 | |||
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diyAudio Member
Join Date: Jan 2011
Location: Ladysmith, BC
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Quote:
* There are some of your drivers I don't think sound good, admittedly. Quote:
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Recently Dayton released a new line of drivers called the Designer Series. All their data show a similar set of reflection blips in the measurements. I'm quite sure they are related to the measurement setup. Scanspeak's 15Wu474 and 12Mu473 also have show this effect. Look at the saw teeth at 28, 38, and 70hz in all three measurements. That's a reflection no doubt considering the low frequency. Does that mean I think you, Dayton, scan speak and many others do a poor job of measuring? No. Would you care to see some of my measurements so you can pick them apart? I'd actually appreciate the criticism. The only MA product I've measured is the EL70 though. Measured quite well imo
Last edited by markaudio; 19th April 2012 at 04:30 PM. Reason: Removing commercial conflict |
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#18 | |
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diyAudio Member
Join Date: Jan 2011
Location: Ladysmith, BC
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Quote:
Every measurement has reflections. You know this. Perhpas there was a reflection that corresponds to 500hz? If not, great, easy for you to answer. In which case the saw teeth are a real part of the drivers performance. That's all I wondered. The unfortunate part of Bob's measurements is, I too believe they are raw, but they're in room. In room measurements shouldn't be raw unless certain techniques are implemented (close mic, measuring in a very large room, etc.). They're impossible to read and include the effects of the room. Move the mic or speaker and the measurement changes dramatically. Even at 1/2m like Bob did. Measuring a complete speaker at 1/2m introduces other issues also. What I mean is, this is a bad example of your drivers frequency response, imo. |
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#19 | |
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diyAudio Member
Join Date: Aug 2002
Location: victoria BC
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Quote:
- for more than a few reasons I've long not been particularly a fan of measurements; pretty or theoretically optimal results are far too often pursued at the expense of what many would consider the "fuzzy / subjective / elusive" goals of musicality - I don't have the technical expertise* to debate these issues, so don't take my silence as affirmation (* to quote ms O'Connor - "I do not want what I haven't got") - AFAIC once an audio system is in a room playing music, all the pretty anechoic or test bench measurements in the world are meaningless, and even the most sophisticated EQ/room correction etc etc will not likely perfect things for all listening positions
__________________
you don't really believe everything you think, do you? community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi |
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#20 |
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diyAudio Member
Join Date: Jan 2011
Location: Ladysmith, BC
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Chris, my comment wasn't meant to put words in your mouth. All I meant by it was at first it seemed you misunderstood my query, and then understood. Sorry.
As far as your views on measurements. Thats nice. It's still of great interest to me. It recently occured to me while Kyle and I were emailing that measuring is probably the most enjoyable part of DIY speakers to me. So my enquiry isn't a way to quantify how Mark's drivers sound. In fact, I'd agree with you that a single on axis FR means very little in terms of sound quality. My enquiry is more about the interest I have in data, and how this particular set of data should be interpreted. |
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