One more question, if you will indulge it, @profiguy and others, as since they are domes I hope it is reasonable in this thread. Perhaps you don't have firsthand experience as with the other drivers being discussed, but do you, or others, have any thoughts on Bliesma's M142 series, in particular the "A" and "T"?
https://hificompass.com/en/reviews/bliesma-m142a-6-7-almg-dome-midrange
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m142a-6
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m142t-6
Thank you,
Bill
https://hificompass.com/en/reviews/bliesma-m142a-6-7-almg-dome-midrange
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m142a-6
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m142t-6
Thank you,
Bill
@Bill Brown I don't have extensive experience with the M142A, but had a production sample for a very brief evaluation period thanks to a fellow here on the forum. This is a very low compromise driver in many ways and likely one of the best drivers currently available based on its bandwidth capability.
The thing that stands out first off is the unrestricted rear radiating surface. There's really nothing that would hold it back used as a dipole. Overall, its the most capable large dome I've ever come across in this regard and the least encumbered in terms of linearity, transparent reproduction and sheer dynamic capabilities in its advertised band width. Perhaps a very large Raal ribbon could compliment it and keep up, especially when used in a dipole. Its just such a unique driver, not just in the way I mentioned. Its hard to make any other comparisons with other drivers because there really are no others like it.
There's no doubt they designed the M142A to mate up with the M74 family of mids. The distortion is so low that it could easily cross around 250 hz 2nd order. The huge VC isn't likely going to complain with the electrical demand. There's plenty of xmax for sub 300 hz HP to keep up with a pair of very capable 12" LF drivers.
I wish I had a pair of these drivers to audition. They'd definitely meet my expectations for a midbass region driver with the agility and character to keep up and transition to the M74A.
My only other readily available, obvious choice for a well matching LF driver is the SB WO24TX. That one is over $400, so there's no cheap solution to something that would for sure combine well with the M74A/B/T.
The biggest hindrance is the lack of high sensitivity midbass drivers with low enough distortion to mate with a driver like the M142A. For my own needs, the Eminence Neo 10s are a good solution, as they have very low HD up to 600 hz at the levels I want to get from the entire design. The durability is the other reason, so the odd transient won't damage anything on the low end. This is considering I listen to analog sources with the occasional infrasonic "surprise" lurking to take out a woofer from overexcursion. A DSP setup would just employ a hard limiter to solve this issue.
So that's about all I can tell you about the M142A. Its definitely not a driver for novice builders. It needs too much special attention to get the best from it. This considers the inherent need for a proper enclosure which is rather critical with this driver.
The thing that stands out first off is the unrestricted rear radiating surface. There's really nothing that would hold it back used as a dipole. Overall, its the most capable large dome I've ever come across in this regard and the least encumbered in terms of linearity, transparent reproduction and sheer dynamic capabilities in its advertised band width. Perhaps a very large Raal ribbon could compliment it and keep up, especially when used in a dipole. Its just such a unique driver, not just in the way I mentioned. Its hard to make any other comparisons with other drivers because there really are no others like it.
There's no doubt they designed the M142A to mate up with the M74 family of mids. The distortion is so low that it could easily cross around 250 hz 2nd order. The huge VC isn't likely going to complain with the electrical demand. There's plenty of xmax for sub 300 hz HP to keep up with a pair of very capable 12" LF drivers.
I wish I had a pair of these drivers to audition. They'd definitely meet my expectations for a midbass region driver with the agility and character to keep up and transition to the M74A.
My only other readily available, obvious choice for a well matching LF driver is the SB WO24TX. That one is over $400, so there's no cheap solution to something that would for sure combine well with the M74A/B/T.
The biggest hindrance is the lack of high sensitivity midbass drivers with low enough distortion to mate with a driver like the M142A. For my own needs, the Eminence Neo 10s are a good solution, as they have very low HD up to 600 hz at the levels I want to get from the entire design. The durability is the other reason, so the odd transient won't damage anything on the low end. This is considering I listen to analog sources with the occasional infrasonic "surprise" lurking to take out a woofer from overexcursion. A DSP setup would just employ a hard limiter to solve this issue.
So that's about all I can tell you about the M142A. Its definitely not a driver for novice builders. It needs too much special attention to get the best from it. This considers the inherent need for a proper enclosure which is rather critical with this driver.
How would one integrate m142 with m74?
What crossover points one would look?
I mean we want to avoid 1k-3/4k region, right? So would it be excessive to use such a expensive driver as a midbass/low mid driver, or needed when going for highest fidelity?
One "kind of" example i found was Marten Coltrane Quintet which has 3 drivers from 170hz. https://www.marten.se/products/coltrane/coltrane-quintet/
170hz-1k - Convex carbon midbass
1k-6k - beryllium dome
6k-60k - diamond tweeter
What crossover points one would look?
I mean we want to avoid 1k-3/4k region, right? So would it be excessive to use such a expensive driver as a midbass/low mid driver, or needed when going for highest fidelity?
One "kind of" example i found was Marten Coltrane Quintet which has 3 drivers from 170hz. https://www.marten.se/products/coltrane/coltrane-quintet/
170hz-1k - Convex carbon midbass
1k-6k - beryllium dome
6k-60k - diamond tweeter
I would not choose those frequencies.
When you are ok with a higher cross over of the M74 (they are for sure) I would go
600Hz - 3-3,5kHz M74B
When you do proper digital crossovers these "avoid" rules are to see different. When you can avoid strong vertical lobing and delays between drivers ... the real goal is to avoid that the cross over is audible at all.
I'm sorry bit that tweeter really looks like a LED COB lamp 🤓
With the right design you could perfectly hide it for small PA 😛
More serious - what tweeter is that and what horn and how low can it go? Radian?
That's also what I heard with crossover - but very slightly. I prefer the M74B way, it sounds more "natural" to me. Like AL tweeter vs. B tweeter.
I would say it's the heavier membrane. M74B has better sensitivity -> lighter membrane.
I had good results for avoiding these peaks with a different solution - a passive high cut. The coil in series also provides damping and was good enough to push THD down. I also tried 2nd order to get a good fitting of the FR. But first step is always to try a notch filter.
When I don't do a passive circuit at least I set a big notch digitally to extra dampen the signal in this area, so you really don't send anything to the driver there.
The Coltrane id say uses version more like Bliesma w137 as surround looks like inverted rubber surround for longer throw than M142
You could also use a SB acoustics MW19TX as mid woofer to go with M74B/A if you are doing a 4way.
That's also one of my main goals and this get's the "basic" foundation to have precise reproduction in my opinion. Such a concept will always have a cirtain amount of "control" over the sound.
I also don't get how much resonantors are used for low frequencies, also in big and expensive concepts.
Very good off axis linearity helps that your speaker sounds as your speaker in every room. But that's not a big thing here I would say?
This sounds like a great room! Would love to see a photo (esp the ceiling) or a sketch. What is on the back wall - diffusion?
There is a great .pdf about these wood slat diffusors on top of absorption "Sound Absorption of slat structures for practical applications". Many of these constructions have too much opening area and are not diffusing (or 10-20%). That's probably why they sound so good ;-) cause they always also have a good amount of absorption.
Rear speakers do so much for an "enveloped" feeling. Mine are way too close and still there is an upgrade with 4 instead of 2. But music is more sensitive as movies in this regard, it needs to be set up carefully.
Do you have a sketch of your listening position?
One thing which comes to my mind immediately with your room is "soft soffit". Putting your speakers IN your front wall!
I like to do this for cinema installations (RCL ;-)) and you totally chancel lambda/4 resonance with the speaker back wall. And most other fast reflections from furniture and objects around it. Normally I just put a screen with acoustic transparent fabric over it and you hide everything perfectly - and get perfect natural sound from "nowhere" which is a GREAT effect when you just want to listen to the music and have no thought about the tech and speakers behind it! I really enjoy this in my living room.
Where your speakers are positioned is part of the over all concept. When you can manage to put them on/in your front wall (reflective or absorptive) you have a solid start for the rest of the build.
That's also what I always say - when you have a great room, think about wide dispersion. Especially when you want your sound "around" you cause it will get precise and direct when you control your reflections (what I really love and need for work and listening but not everyone want's to hear how the sound engineer had murdered that remix/remaster 😎)
I would probably go for direct radiation and the great detail and dynamics of the Bliesma domes in your case.
When you already have the T34Bs I would go with M74T for them and woofers fitting your room. When you don't need the low end you can have a look after PHL 10" speakers or some other higher sensitivity drivers. Where do you cross over to your woofer system?
I have a concept where you use Dirac Live and 7 speakers with 14 12" drivers which also work as distributed subwoofers and Dirac Live does the calculations of the "double array" cancellations. Done right (and in your room you could do so) you can do EVERYTHING with such a system from perfect Stereo to some immersive Stereo to every Surround format you would like. But yes ... this is not cheap 🤓
But very likely the last time you pay for speakers.
The DAC is the bottle neck with these plate amps! They actually plan to do an upgrade of the amp module later this year but as long as they don't upgrade their DACs ...
But to be fair, when you use the digital input you have a better S/N range as every multichannel preamp + power amp in the market. Fidelity is not the problem of these modules.
You have a great room and are on your way to a great concept ... you will be listening to great music soon! 🙂
Hey, I am sure it is OK to ask. Most people posting here know way more than I do, but from what I have gleaned from early pages here, like page 3, the D54 may need a higher crossover than you want to use. The same consideration with most of the other domes listed/discussed. Few seem to have an Fs low enough to cross below 500hz.
In my limited experience, I think that a nice cone can give the sub 500hz lower mids more realistic "body" and "size" than a dome mid. I know next to nothing about monitoring/mixing, so there may be considerations that are more important than realistic in-the-room sense of, for example, the realistic size of an acoustic guitar or cello. I think a larger diaphragm does this better, at least for HIFI listening.
If you are willing to experiment with an additional rear cup/enclosure, I quote the OP here:
"I know a lot of people complain that the (Scan Speak) D7608 has no enclosure but that's actually a blessing in disguise, allowing you to adjust Qts and Fs (to a certain extent) to suit your needs. Being able to change sub enclosure design parameters allows this mid to sound its best.
If you look up the measurements on Hifi Compass about the D7608, you'll find the CSD is very clean in the pass band as well as excellent step response. This mid is a bargain for what it costs and the amount of flexibility you have to implement it correctly for your specific design".
The main issue I have with most plate amps is in fact compromised DACs. In my recent search for a DAC that didn't impart its own flavor, I finally found the RME ADI2 Pro FSR. This is so far the only DAC I have owned that didn't impart any audible flaws of its own into the source. The last CD player I owned that was close in performance was the NEC CD830 with its dual TDA1451A crown converters.
@VincentDano @howardg That post slipped through the cracks. Sorry.
The Dynaudio D54 isn't capable of much output below 700 hz, at least not enough to hang with a larger high sensitivity LF driver. I've used all of the Dynaudio mid domes. The two with the most potential are the D76AF and D52AF. The D76 can cross at 500 hz 2nd order no problem, but it doesn't play that high, at least not high enough for decent SPL from most 1" HF domes. D52 can play pretty loud with an 800 hz 2nd order HP and will do pretty well with a 5k LP. Most decent 1" tweeters will cope with a >4k+ HP playing 105 dB+ total system output. I haven't yet taken out a tweeter using this common sense approach. Any WGed tweeter will do better in this regard and provide even better reliability in the process.
The Dynaudio D54 isn't capable of much output below 700 hz, at least not enough to hang with a larger high sensitivity LF driver. I've used all of the Dynaudio mid domes. The two with the most potential are the D76AF and D52AF. The D76 can cross at 500 hz 2nd order no problem, but it doesn't play that high, at least not high enough for decent SPL from most 1" HF domes. D52 can play pretty loud with an 800 hz 2nd order HP and will do pretty well with a 5k LP. Most decent 1" tweeters will cope with a >4k+ HP playing 105 dB+ total system output. I haven't yet taken out a tweeter using this common sense approach. Any WGed tweeter will do better in this regard and provide even better reliability in the process.
The SS D7608 and Seas T35C002 are an excellent match crossed at 3k. You can definitely cross the tweeter lower being almost 1.5" diameter and certainly moreso with a WG. The issue with a WG is the CTC increases substantially. A shaded pair of D7608 HPed at 500 hz 2nd order will easily keep up with a larger sensitivity tweeter and exhibit low THD in the lower mids.
A good alternative to the pricy T35C002 is the Audax TW034. Its less than $100 and pretty well behaved for a big HF dome. It just won't cross under 2.3k without a WG and some internal mods. The OE foam cap on the pole piece of this tweeter needs to be replaced with a wool felt type. That cleans the wrinkle it has at 2.2k.
A good alternative to the pricy T35C002 is the Audax TW034. Its less than $100 and pretty well behaved for a big HF dome. It just won't cross under 2.3k without a WG and some internal mods. The OE foam cap on the pole piece of this tweeter needs to be replaced with a wool felt type. That cleans the wrinkle it has at 2.2k.
Last edited:
SS D7608 and Audax TW034 seem quite nice for my purposes. Thank you for your expertise @profiguy . Low THD in the lower mids is really what I am trying to aim for. I have just seen and heard ATC (e.g in their SCM25 Pro) cross over at around 380hz which made a lot of sense to me due to the avoidance of potential phase issues + crossover distortion (I may very well be wrong as well, this is just what I deduced).
My need for a music-oriented cafe was 40~20kHz JBL-ish speakers with neutral voicing that could play quite loudly, adaptable to different rooms/settings, and not expensive. It had to be done fast. The project began conceptually at the end of March & final voicing was done last week, around 2 weeks after construction began. Finishing is scheduled to be done elsewhere starting later this week. They'll be retuned at the final location for the first opening in ~3 weeks.
I opted for 2-way with miniDSP for the speed & flexibility of DSP/PEQ & SB Audience pro drivers, including ROSSO-44CDN-PK CD with 600Hz B52 PHRN 10x14" 90x60 horns -- long discontinued, AFAIK, themselves clones of a QSC horn. Had these for a few years waiting for a suitable project.
The CD is recommended to be crossed at 1.8 khz but it runs flat to a bit below 800hz, and distortion isn't a factor even when SPL exceeds 100 dB. I tried many settings between 800 & 1800 Hz. So far 800 Hz LR4 sounds & measures best.
@VincentDano The SCM25 is a nice sounding speaker. They make good use of the big dome.
If you like that type of sound, you'll also like the D7608 with the TW034.
That ATC SM75-150 dome does most of the critical range but it has some weird sharp dip around 3.7 - 4.3 k that gets worse off axis. Its most likely due to the built in WG but won't have much affect on the summed FR.
With the TW034, the extra meat down low will allow for an offset mid LP slope on the D7608, helping the tweeter tie the summed response together. Just stay between 3 - 3.5k LR2 for the crossover if you want decent transient response.
If you like that type of sound, you'll also like the D7608 with the TW034.
That ATC SM75-150 dome does most of the critical range but it has some weird sharp dip around 3.7 - 4.3 k that gets worse off axis. Its most likely due to the built in WG but won't have much affect on the summed FR.
With the TW034, the extra meat down low will allow for an offset mid LP slope on the D7608, helping the tweeter tie the summed response together. Just stay between 3 - 3.5k LR2 for the crossover if you want decent transient response.
Last edited:
The SB 44CDN-PK is a good driver. I haven't used it that low, but it did sound rather relaxed at about 1.4k
nice, thanks very much, I will look into this combo a bit further. your time is greatly appreciated!
I think it is the combo of this 1" CD and the biggish 14x10 horn that allows the extended low response. The horn is spec'd to reach 600 Hz.
The official FR shown for the 44cdn-pk is with SBAs own 10" square horn. It starts rolling off at 1khz.