In Tractrix 200 i prefered DCM50 instead of JBL2450SL with Truextent because it could be crossed over as low as 400 Hz and low pass was around 3000 Hz. DCM50 sounds very very good in that frequency range.
Breakup is there - from about 12k, but I haven't noticed it (and I'm sensible to harshness).
The plots were from the Gran Gioia 2x10” and Gran Gioia MkII respectively.
BH prefers to use 3" drivers, mostly with relatively small horns and waveguides.
Few modern 1" drivers sound pleasant with a low xo point (<1000 Hz) and adequate horn loading is important in that case (to keep distortion within acceptable limits).
Do you know the crossover details (electrical order on each branch, autoformer/Lpad, etc)?
Anular ring type is not excursion constrained by the phase plug distance (good but then more work on suspension and magnet needed to enable this excursion and more IMD if the diaphragm is not made larger), has a smaller surface area for outer diameter (bad), inner and outer clamping of the diaphragm pushes the breakup frequency higher though (good and enough to counter the smaller surface area if the driver is made larger). If well designed it's the superior design. The highest output midrange compression drivers are ring type from BMS.
Comment by Jørn Rune Kviserud:
"As more recent research has shown, if we look away from Wente and Thuras work in the 20's determining some of the effects of the compression chamber with surprisingly high precision, the main problem of compression drivers are the artifacts in the phase plug. The two main factors are higher order modes originating from changes in the wave front shape in the drivers exit, and circulating modes in the phase plug causing audible modes, alterations to the frequency response, alterations to the wave front, contributions to cavity resonances in the compression chamber, causing uneven pressure on the diaphragm, causing timing errors in multiple places within the driver etc.
This is such a significant factor that comparing diaphragms in a compression driver is extremely hard. The resulting effect does not resemble the actual difference in the behavior of the different diaphragm materials. Even drivers with diaphragm modes throughout their working range sometimes seem like they perform well on paper, but oposing modes does not result in good sound.
One will simply need to redesign the phase plug in order to achieve high end performance from a compression driver."
"As more recent research has shown, if we look away from Wente and Thuras work in the 20's determining some of the effects of the compression chamber with surprisingly high precision, the main problem of compression drivers are the artifacts in the phase plug. The two main factors are higher order modes originating from changes in the wave front shape in the drivers exit, and circulating modes in the phase plug causing audible modes, alterations to the frequency response, alterations to the wave front, contributions to cavity resonances in the compression chamber, causing uneven pressure on the diaphragm, causing timing errors in multiple places within the driver etc.
This is such a significant factor that comparing diaphragms in a compression driver is extremely hard. The resulting effect does not resemble the actual difference in the behavior of the different diaphragm materials. Even drivers with diaphragm modes throughout their working range sometimes seem like they perform well on paper, but oposing modes does not result in good sound.
One will simply need to redesign the phase plug in order to achieve high end performance from a compression driver."
With so much that can go wrong, it is a small wonder we still enjoy our music that comes out of them 🤣
When you only consider the usual metrics, most annular comp. drivers seem superior to their traditional dome counterparts... and yet, with the exception of the large BMS Coaxials, why don't we see annular drivers in almost every horn-loaded hi-fi speaker?
Let's take an example: the B&C DE360.
Performance seems almost sublime (distortion, STFT etc.).
On the basis of this data you'd say: a no-brainer.
However, several people have tested this driver in actual projects and the experiences have not exactly lived up to the high (hyped) expectations.
In this comparative test Troy (Joseph Crowe) illustrates the (sonic) superiority of a basic dome comp. driver.
Honestly I think when equalised and used at comparativly low levels and high frequencies on the same horn they will sound more simlar than different (small polymer domes and anular rings). I don't agree with listening for small changes in sound this way its very unreliable. A better approach is to record each driver using a high quality microphone and then listen back with headphones if you want to listen for audiable differences that way you can swap back and forth quickly. If you want to listen this is the way: https://www.diyaudio.com/community/threads/high-frequency-compression-driver-evaluation.212240/
I'm aware of this test and consider it a plausible method for comparison.
However, for me (and many others) there's only one ultimate test, the listening experience of the driver in a system.
Troy isn't the only one who had disappointing experiences with the B&C DE360.
I own a number of BMS drivers. They're not bad, but just don't sound as natural as my dome comp. drivers. This is especially noticeable with voices.
However, for me (and many others) there's only one ultimate test, the listening experience of the driver in a system.
Troy isn't the only one who had disappointing experiences with the B&C DE360.
I own a number of BMS drivers. They're not bad, but just don't sound as natural as my dome comp. drivers. This is especially noticeable with voices.
@Patrick Bateman seemed to really like the eminence N151M-8 ring driver (at one point)?
I’ve thought about trying it in a 3 way. https://audioxpress.com/article/test-bench-eminence-n151m-8-1-compression-driver
I’ve thought about trying it in a 3 way. https://audioxpress.com/article/test-bench-eminence-n151m-8-1-compression-driver
Well spotted 😉
Blumenhofer speakers clearly deviate from the mainstream. The founder/owner/designer is a man of few words, but he possesses knowledge, experience and urge to create.
His biggest boys.
Blumenhofer speakers clearly deviate from the mainstream. The founder/owner/designer is a man of few words, but he possesses knowledge, experience and urge to create.
His biggest boys.
It's the best performing wave guide I've ever seen, at least on the QSC waveguide and it's various clones.
If it was $200 each it wouldn't be such an obvious choice, but at $95 each it's a world beater:
https://www.loudspeakersplus.com/Eminence-N151M-8-Ring-Radiator-p/eminence-n151m-8.htm
I used to be a big fan of some of the small JBL and Celestion compression drivers, but part of that was because you could get them as spare parts for around $35-$65 each. Those prices went up quite a bit:
https://www.parts-express.com/Celestion-CDX1-1425-Neo-1-Compression-Driver-25W-294-2132
They're still great drivers but at 2-3X the price, a little less compelling.
On top of all that, the waveguide makes a huge difference obviously. For a while there I had speakers in my living room that used Celestion's least expensive compression driver, and in my loft that use the same. Despite using the identical compression driver, the two sounded completely different. That's part of the reason I like keeping some QSC waveguides around, allows me to do "apples to apples" comparisons. But that opens ANOTHER can of worms, which is that the reason the N151M performs so well in my tests may simply be that it's a particularly good match for the QSC waveguide.
I have eight of them, if you want a couple I'll list them in the yard sale forum
Prices for drivers have increased enormously in the past 3 years.
So I immediately grabbed another pair of my favorite 1" drivers when someone put some leftover parts up for sale a few months ago.
€80 for a pair, new in box instead of €253 each, in some stores that still have them in stock.