HSB has scrutinized this little 3" bird from China (DM 7500) with very good results :
https://hifi-selbstbau.de
Full extended report only for members ($25/yearly subscription) , incl. passive filter network making bandpass FR flat to +/-1dB along the filter function ...
Don't ask me for giving away copies of the results of HSB test report , I'm just here because I don't like the extreme prices of ATC and VOLT ... and you'll see there are cheaper alternatives!
Btw - in the report they mentioned the idea to mount the dome driver from behind the baffle , and shaping the contour similar to the front plate profile of the DM7600 , nice idea! (fabric dome is very exposed due to large height)
A man without a hobby is braindead 🙂
https://de.aliexpress.com/item/1005004670052234.html
https://de.aliexpress.com/item/1005006747187144.html?src=google
https://hifi-selbstbau.de
Full extended report only for members ($25/yearly subscription) , incl. passive filter network making bandpass FR flat to +/-1dB along the filter function ...
Don't ask me for giving away copies of the results of HSB test report , I'm just here because I don't like the extreme prices of ATC and VOLT ... and you'll see there are cheaper alternatives!
Btw - in the report they mentioned the idea to mount the dome driver from behind the baffle , and shaping the contour similar to the front plate profile of the DM7600 , nice idea! (fabric dome is very exposed due to large height)
A man without a hobby is braindead 🙂
https://de.aliexpress.com/item/1005004670052234.html
https://de.aliexpress.com/item/1005006747187144.html?src=google
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Here's a cheaper place to buy DM-7600
https://aliexpress.ru/item/10050067...spm=a2g2w.stores.seller_list.5.66e93b5ebbAwg1
https://aliexpress.ru/item/10050067...spm=a2g2w.stores.seller_list.5.66e93b5ebbAwg1
In the HSB report they said the fabric dome of the DM7500 is not sticky , unlike the old Dynaudio domes , that coating collected dust like crazy and is getting a disgusting look after 2-3 years ... but to be sure I would like to test a "lotus effect" coating which you can spray on lightly to the surface . For special/critical drivers I buy always 3 pieces so I can select for closer tolerances and use the leftover one for experiments/modifications!
Also I want to see all the details inside of the driver , removing ferrofluid from the air gap is another option! (can be re-filled)
I envision a nice compact 3way speaker coming up my memory lane , a faint touch of yesterday in the shadows of things ...
Also I want to see all the details inside of the driver , removing ferrofluid from the air gap is another option! (can be re-filled)
I envision a nice compact 3way speaker coming up my memory lane , a faint touch of yesterday in the shadows of things ...
Btw - the HSB report has a statement included about the Dynaudio D76 that is wrong (afaik) ... to my knowledge the D76 never had ferrofluid in the air gap! (unlike the D52/D54) ... but the coil overhang was non-symmetric to compensate for higher air stiffness in negative direction giving less harmonic distortion!
I used these in a three-way that I took to InDIYana in April. They were really well received. I crossed over at 650Hz and 3500Hz, I know someone else who used them and crossed over at 550Hz. In the U.S., Parts Express has 10-12% off sales pretty much every holiday, so I consider these a $90 midrange. For those situations where a 3" dome works, these are pretty darn good for the price.
Not sure how useful these are, but here are MY measurements in a faceted baffle (pic of baffle at the end).
Raw measurements on baffle at 1 meter
Measurements with crossover at 650Hz and 3500Hz
Distortion
Shape of my baffle. (Dayton Audio AMT 2-4; HiVi DM7500; Dayton Audio RS270P-4A)
Not sure how useful these are, but here are MY measurements in a faceted baffle (pic of baffle at the end).
Raw measurements on baffle at 1 meter
Measurements with crossover at 650Hz and 3500Hz
Distortion
Shape of my baffle. (Dayton Audio AMT 2-4; HiVi DM7500; Dayton Audio RS270P-4A)
Btw - in case of high resolution - low distortion drivers , Distortion Consistency (DisCon) becomes seriously significant! It is needed to measure more than one driver and select a low tolerance pair for hi-quality stereo requirements!
And do not forget - woofer and tweeter distortion is "bleeding" into the "blackness" of the midrange channel , altering & worsening his absence of distortion!
Blackness means here , simulate perfect driver & network , then reverse the midrange channel and see the maximum deepness/cancellation you can achieve with that configuration!
And - remember according to textbooks about hearing , maximum pitch resolution is around 880Hz!
Center freq between 40Hz and 16.000Hz is 800Hz!
Designing 3way speakers is much more complex than 2ways!
2way speakers are deceivers 🙂
Blackness means here , simulate perfect driver & network , then reverse the midrange channel and see the maximum deepness/cancellation you can achieve with that configuration!
And - remember according to textbooks about hearing , maximum pitch resolution is around 880Hz!
Center freq between 40Hz and 16.000Hz is 800Hz!
Designing 3way speakers is much more complex than 2ways!
2way speakers are deceivers 🙂
Distortion goes a bit wonky below 2KHz doesn't it? Can @Marveloudio comment if the HSB plots show the same rise in distortion below 2KHz that @A4eaudio shows?
A4audio shows only 90dB level while HSB shows from 80 to 110dB in an animated GIF file , only 2 seconds long , difficult to read . Around 90dB similar , above slowly rising , K2 dominating , K3 much lower maybe 6-9dB , again hard to read .
As always - do a prototype first and hear/measure before investing tons of money!
Have a Plan B for your drivers if prototype expectations fail!
As always - do a prototype first and hear/measure before investing tons of money!
Have a Plan B for your drivers if prototype expectations fail!
At least one error is in the HSB report : "Das periodenskalierte Zerfallspektrum zeigt ein verzögertes Ausschwingen um 1 kHz"
But the diagram shows a linear time scale , not a periodic one!
Means it looks much worse than it is in hearing related terms ...
Very good to excellent is the dome to dome FR linearity and stability over level!
Enuff said , buy those damn' $25 subscribtion and cancel timely enough , it was the work of an german engineer working for FORD car acoustics in germany for many years he knows his stuff ... time to respect hard work , even it is "only" hobby stuff ....
But the diagram shows a linear time scale , not a periodic one!
Means it looks much worse than it is in hearing related terms ...
Very good to excellent is the dome to dome FR linearity and stability over level!
Enuff said , buy those damn' $25 subscribtion and cancel timely enough , it was the work of an german engineer working for FORD car acoustics in germany for many years he knows his stuff ... time to respect hard work , even it is "only" hobby stuff ....