ok but what B&C driver? some of them I would say are of comparable quality (depending as well on application) as TAD. A DE250 is going to sound different to a DE750TN. I would be concerned about over generalisation that high end compresion drivers are never worth it as often the expensive features are things like capability for low crossover. A good data point though that the TAD driver was not magical though 😉
Excuse me but isnt that a little "sloppy" being scientific about it - I mean proper documentation? I presume you did the outmost to get as a clean and resolving system as absolutely possible!?
Hand on hart - you didn't go into that experiment with the already set mind that distortion "shouldn't" matter?
//
Hand on hart - you didn't go into that experiment with the already set mind that distortion "shouldn't" matter?
//
so linear regression analysis using a single data point? No worries, I have done that too. 😉
At this point in my personal experience with horns, I think the problem is not the CD itself but the horns. Something that sounds good is BIG, expensive and needs to extend well below the xover frequency.
Plenty of drivers out there, BMS are cheap, have low distortion and sound great. Anything suggested in this thread will work.
Earl, without subjective opinions over "domination", the difference between different drivers on the same waveguide can be large, as can be clearly seen in this comparison:
https://www.diyaudio.com/community/threads/high-frequency-compression-driver-evaluation.212240/
If equalized to the same response, the drivers sound similar within excursion limits, but without EQ, the difference in drivers may be both measurable and audible.
Art
Hi Art
The two identical systems were separately EQ'd to be as close as possible.
Did they sound "different", probably. Was this difference significant to the 30 subjects? No.
I'm not going to get into an argument nit-picking the test. No psychoacoustic test is ever perfect, but if it's done correctly it presents a data point. One data point based on a controlled, blind, multi-subject, that is statistically significant is worth more than thousands of data points from uncontrolled person opinions.
This data point indicates that the drivers can be made to be insignificant aspects of a good design.
As to suggestions that we deliberately biased our tests, that's insulting.
Isn't that a little bit of apple and oranges comparison? The white, orange and magenta curves: what drivers are they? 🤔
I wasn't insulted by your comments, it's just that this was so long ago and I don't remember the details. Even though it was documented at the time, I am not about to go dredging up those reports. I remember the results very well, but not the details of the test.
The driver was likely either a DE25 or DE250. I used both. Later on I used the DE500, but it didn't have the bandwidth of the DE250 and could only be used if the system was active instead of passive.
The driver was likely either a DE25 or DE250. I used both. Later on I used the DE500, but it didn't have the bandwidth of the DE250 and could only be used if the system was active instead of passive.
If driver "A" is an apple, and driver "B" is an orange, and your mouth is a horn/waveguide, then yes 🙂
"82on" is an B&C DE82
"1Aon" is an Electro Voice DH1A16
"02on" is an Eminence PSD2002 (Series 1 diaphragm, less VHF, smoother response than Series 2 diaphragm)
The PSD2002 is an example of a "commodity" driver with response that requires extensive EQ to sound decent, and every one I've tested has a different response- you'd need different EQ for each driver.
"50on" is an BMS 4550
"52on" is an BMS 4552
"PAon" is an Jensen Hypex D-30, an antique with no phase plug, hence the acoustical low pass killing the HF response.
At any rate, some drivers sound more alike, and some sound a lot different, and the EQ required to flatten one driver's response may sound horrible on another.
Art
Last edited:
This is a big problem! Consistency is imperative. B&C once made a "running" change for some reason and it totally screwed up my crossover design. They were consistent however both before and after the change.
When was the change made to the DE250? Was it the motor or the diaphragm asy? I use the current 16 ohm verion which has a bit smoother and cleaner performance down low than the 8 ohm. Doesn't make much sense being they both use the same diaphragm design and appear the same construction. The winding thickness on the 16 ohm version is a few thousandth thinner, giving more clearance in the VC gap. I have a feeling this driver has been dumbed down by B&C to compete less with their higher end models.
That is not accurate at all in my experience of comparing 20 or so different drivers. The majority were meh or bad including various premium B&C drivers. I agree that extension is pretty critical when selecting a driver, I do not understand the point of a compact compression driver that does not extend to 20khz and requires a supplementary tweeter. In my test only four drivers were exemplary, the Beyma CP755ND, Altec 288, Faital HF108, BMS 4552. And of those four, all of which I would consider extended and fundamentally capable, each presented a different flavor of mf and hf tonality.
Last edited:
milezone, I saw you are selling many of your drivers in the swap met, Beyma 755 as well ! New design philosophy ? (ok sorry, off topic)
Btw have you an experience of the BMS 4550 over the 4552 ?
Btw have you an experience of the BMS 4550 over the 4552 ?
I bought an extra CP755ND as a spare which I decided I do not (sorry my apostrophe key is broken on my keyboard) need given that I have a spare set of diaphragms. Same design philosophy to some extent though I am planning to experiment with a three way configuration including the CP755NDs for mid highs and highs, and a pair of 10inch drivers from 100hz to 1000ish hz. The reason is I do not find the 15 inch 15G40 which I am using to be a suitable driver for mid frequencies. And there is a perceptible dip around the 700hz crossover point of the two way. These should be alleviated by the addition of the 10 inch mid driver, along with improved bass performance. I do think a design like Gedlees 12 inch two way plus subs is the right way to go. I am basically using a single or pair of 10s per channel instead of 12s and will use the 15G40 drivers which I own as subs. I designed the enclosure housing the 15 inch drivers to have a removable baffle. I will probably swap the 15G40s for a pair of 18s eventually.
On a slightly different note, I just returned from auditioning a turntable setup which I am considering purchasing. The listening room consisted of 1000w CH Precision amps and Magico M6 speakers. These speakers are way outside the realm of a normal budget however it was nice to hear a very performative pair of direct radiator, sealed enclosure three way speakers. I understand Magico has gone to great lengths to achieve incredible cabinet rigidity and I think this more than anything is essential to the success of these speakers. I typically scoff at ultra high end speakers though the M6s sound outstanding, and especially given that they rely on a passive crossover network. Comparing with my wave guide two way system, the Magicos are more refined. They do not have the same sense of headroom and power, however they do posses a level of coherence and refinement that my system is lacking. The CP755NDs are raw by comparison. I think they can be tamed by improving the enclosure -- increasing the volume of the rear cover or removing it for dipole operation. I maintain my observation that this particular driver delivers as much detail as any conventional driver that I know of and if one is building a pair of speakers on a practical budget, they would be hard pressed to do better. The BMS 4552 is more tame though not as exciting to listen to. Hearing the Magicos reconfirmed my sentiment that excessive horn loading and the color imparted by it does not suite my taste at all. The waveguides which I am currently using, which sound excellent, are the limit of what I would tolerate for a midfield speaker.
On a slightly different note, I just returned from auditioning a turntable setup which I am considering purchasing. The listening room consisted of 1000w CH Precision amps and Magico M6 speakers. These speakers are way outside the realm of a normal budget however it was nice to hear a very performative pair of direct radiator, sealed enclosure three way speakers. I understand Magico has gone to great lengths to achieve incredible cabinet rigidity and I think this more than anything is essential to the success of these speakers. I typically scoff at ultra high end speakers though the M6s sound outstanding, and especially given that they rely on a passive crossover network. Comparing with my wave guide two way system, the Magicos are more refined. They do not have the same sense of headroom and power, however they do posses a level of coherence and refinement that my system is lacking. The CP755NDs are raw by comparison. I think they can be tamed by improving the enclosure -- increasing the volume of the rear cover or removing it for dipole operation. I maintain my observation that this particular driver delivers as much detail as any conventional driver that I know of and if one is building a pair of speakers on a practical budget, they would be hard pressed to do better. The BMS 4552 is more tame though not as exciting to listen to. Hearing the Magicos reconfirmed my sentiment that excessive horn loading and the color imparted by it does not suite my taste at all. The waveguides which I am currently using, which sound excellent, are the limit of what I would tolerate for a midfield speaker.
Last edited: