Hello,
I would like to know the opinion of other users who have already been able to test the Bliesma M74B-6. Above all, it would be interesting to know what advances it brings compared to other mythical domes such as the ATC SM75-150S. I´m more interested in the sound experience of each one than in technical detailss. Thank you very much for your contributions.
I would like to know the opinion of other users who have already been able to test the Bliesma M74B-6. Above all, it would be interesting to know what advances it brings compared to other mythical domes such as the ATC SM75-150S. I´m more interested in the sound experience of each one than in technical detailss. Thank you very much for your contributions.
It's hard to really do a 1:1 listening test. Just putting 2 different speakers next to each other shows the sound difference of the whole concept, not just the midrange. I'm afraid you have to do this yourself if you really want to compare these drivers.
I did this experimental setup to compare the Bliesma drivers. Not perfect but better a most setups. Just got the M74B, to the listening comparison of A and S I alredy wrote some words.
I would GUESS the ATC will be somehow in the middle between these 2 (membrane harder as M74S but not as stiff as aluminium). You can crossover 100Hz lower and it's proven that it takes a lot of power. But the ATC is way bigger to mount (more distance to the tweeter) and frequency response is not as nice.
My choice is the Bliesma.
I did this experimental setup to compare the Bliesma drivers. Not perfect but better a most setups. Just got the M74B, to the listening comparison of A and S I alredy wrote some words.
I would GUESS the ATC will be somehow in the middle between these 2 (membrane harder as M74S but not as stiff as aluminium). You can crossover 100Hz lower and it's proven that it takes a lot of power. But the ATC is way bigger to mount (more distance to the tweeter) and frequency response is not as nice.
My choice is the Bliesma.
Thank you very much for your answer, JF.
I currently have a medium-high setup consisting of the Bliesma T25B-6 and the Scan-Speak 12MU/4731T00 illuminator and I´m considering trying the M74B-6 instead of the SS since the ATC dome is not currently available. There is a close comparison between the M74B and the Volt VM 753 (https://www.aos-lautsprecher.de/news/), but I haven't read any other opinions about the performance of the M74B-6 (apart from hificompass). Hopefully soon other users will be encouraged to share their experience.
Best.
I currently have a medium-high setup consisting of the Bliesma T25B-6 and the Scan-Speak 12MU/4731T00 illuminator and I´m considering trying the M74B-6 instead of the SS since the ATC dome is not currently available. There is a close comparison between the M74B and the Volt VM 753 (https://www.aos-lautsprecher.de/news/), but I haven't read any other opinions about the performance of the M74B-6 (apart from hificompass). Hopefully soon other users will be encouraged to share their experience.
Best.
I'm pretty sure the M74B is the absolute top for midrange money can buy. The ATC is also there (the Volt is not as good as the ATC but also pretty great), I expect the hard membrane of the Bliesma to be more "natural" and the ATC has an even bigger motor (but less sensitivity). You won't make any mistake with any of these.
Also the M74A should be very close and is way cheaper.
But if you only build one pair and want the best money can buy - just get an M74B and don't thinka about it any more. You won't get a midrange with Beryllium membrane anytime soon elswere.
Also the M74A should be very close and is way cheaper.
But if you only build one pair and want the best money can buy - just get an M74B and don't thinka about it any more. You won't get a midrange with Beryllium membrane anytime soon elswere.
I own the Bliesmas.
I heard the ATCs in ATC and PMC studio monitors. PMC is pretty crazy at their demos and always crank the volume way up. They also give their monitors for events like AES recording competitions and there they fill large rooms with really loud volume - these speakers can deliver. We also had a PCM set in the studio at the university I studied sound engineering. I'm not a fan of their transmission line cabinets (boomy in "normal" sized studio rooms) but the music lives in the midrange and there they are amazing.
I'm not sure about the Volt - I belive they are used in the "smaller" Klein&Hummel or PCM speakers, but not sure if I heard them. But the (rare) measurements you can find online show they are different to the original ATC (resonance frequency is 100Hz higher, frequency response is not as flat).
As the ATCs are hard to find now I don't think there are any 1:1 comparisons, not even sure if it's ever done. But all of these are great drivers, no question.
I showed some measurements here (and in some other post - can't find it):
https://www.diyaudio.com/community/threads/some-speaker-driver-measurements.317632/post-7146705
Depends how loud you play and what THD you can accept - as always with domes (also tweeters). And what LF driver you use, what's it's THD at volume and is it lower as the Bliesma.
Here a measurement at 100dBSpl with different cut of points (active, 24dB/Oct). At 100dBSpl most low frequency drivers have >1% THD.
I will aim for 400-450Hz crossover.
https://www.diyaudio.com/community/threads/some-speaker-driver-measurements.317632/post-7146705
Depends how loud you play and what THD you can accept - as always with domes (also tweeters). And what LF driver you use, what's it's THD at volume and is it lower as the Bliesma.
Here a measurement at 100dBSpl with different cut of points (active, 24dB/Oct). At 100dBSpl most low frequency drivers have >1% THD.
I will aim for 400-450Hz crossover.
Let's have a look.
https://hificompass.com/en/speakers/measurements/scan-speak/scanspeak-12mu/4731t00
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m74b-6
At 8V the ScanSpeak produces about 99dBSpl (and it's a 4R driver!). The Bliesma get's 107dBSpl - way higher sensitivity. Bliesma also has a huge 3" voice coil - will take some power.
THD at 100dBSpl is about 1% for the ScanSpeak - Bliesma 0,1% at 1kHz. Even at 107dBSpl it stays lower.
SS - 5,4g membrane weight. Bliesma 1,8g
Interestingly the Bliesma seem to beam stronger! Didn't expect that. But it's more regular.
Of course you can crossover the ScanSpeak lower. Frequency response is very easy to handle. It's a great driver!
But you get way louder with the mid dome with less distortion.
How is the sound difference? Good question, looking forward to someone doing a comparison ;-)
The other post with some measurements: https://www.diyaudio.com/community/...me-midrange-lineup.380200/page-5#post-7140555
I will do measurements probably next week - what do you want to be measured, maybe I can squeeze it in.
These measurement levels are in 1m. But I'm not sure if mic position is 1m, sometimes I go closer and correct SPL for 1m distance. (to get less room influence)
Here you can see H2 and H3. Higher ones are not prominent. The THD rise at lower frequencies is purely H2, ther is also no rise of H3 at very low crossover frequencies.
These measurement levels are in 1m. But I'm not sure if mic position is 1m, sometimes I go closer and correct SPL for 1m distance. (to get less room influence)
Here you can see H2 and H3. Higher ones are not prominent. The THD rise at lower frequencies is purely H2, ther is also no rise of H3 at very low crossover frequencies.
That´s the key question. We have already read the data obtained by different users, but not the sound evaluation, except for the subjective comments posted by hificompass. This information interests me even more than the technical data, which is also important of course.
What can a high-quality dome offer compared to a high-quality cone? I usually listen to classical music and I am very sensitive to the timbre of the piano. I have the feeling that I cannot hear the timbre of the piano naturally in the recordings, I always have the feeling of artificiality and I doubt if the beryllium dome can provide any improvement in this regard.
The experience of a piano in a room can't be reproduced with stereo recordings. The instrument gives parts of the frequency range in different directions and "interacts" with the room - you would need ambisonics to recreate that.
The T25B is the closest to "natural" sounding with tweeters I know. I have a test track with orchestra and a snare in the background - with the T25A you hear all the details of the playing, with the T25B I have the feeling to hear the TYPE of snare. Or with cymbals - with the T25B you can hear if it's an expensive cymbal with all the fine "crush" resolution or a cheaper one which is a little more rough. (I'm a drummer so that's my references) You can also concentrate on that with the T25A - but it's "there" and easy to hear with the T25B.
ScanSpeak Beryllium are also very good in this regard but I perfer Bliesma for the form factor and the higher membrane resonance.
Not sure how much the mid driver influences this experience. Let's continue the work ;-)
The T25B is the closest to "natural" sounding with tweeters I know. I have a test track with orchestra and a snare in the background - with the T25A you hear all the details of the playing, with the T25B I have the feeling to hear the TYPE of snare. Or with cymbals - with the T25B you can hear if it's an expensive cymbal with all the fine "crush" resolution or a cheaper one which is a little more rough. (I'm a drummer so that's my references) You can also concentrate on that with the T25A - but it's "there" and easy to hear with the T25B.
ScanSpeak Beryllium are also very good in this regard but I perfer Bliesma for the form factor and the higher membrane resonance.
Not sure how much the mid driver influences this experience. Let's continue the work ;-)
I also have the illuminator Scan Speak beryllium tweeter and the Bliesma T25B-6 and I totally agree with your comments.
I know the difficulties involved in recording and playing the piano sound, but there are audiophile recordings that should be close to the natural timbre of the piano, and yet I have always found limitations in playback.
Your question is very relevant, how much the mid driver influences the global sound experience?
I wish someone can share their experience in this regard.
I know the difficulties involved in recording and playing the piano sound, but there are audiophile recordings that should be close to the natural timbre of the piano, and yet I have always found limitations in playback.
Your question is very relevant, how much the mid driver influences the global sound experience?
I wish someone can share their experience in this regard.
Just made THD measurements with 2 M74B.
Measurement distance is 0,5m but SPL level is for 1m distance. No windowing. Just a MTM prototype setup, the A version of the pic above is changed to original M74B.
Remeber - these are 2 drivers! So you have to subtract 6dB.
But still ... that's 0,1% THD at 94dBSpl (which is pretty loud!) And about 0,5-1% at 110dBSpl!
You could easy go 6dB more with these drivers and a proper crossover, probably 10dB.
Measurement distance is 0,5m but SPL level is for 1m distance. No windowing. Just a MTM prototype setup, the A version of the pic above is changed to original M74B.
Remeber - these are 2 drivers! So you have to subtract 6dB.
But still ... that's 0,1% THD at 94dBSpl (which is pretty loud!) And about 0,5-1% at 110dBSpl!
You could easy go 6dB more with these drivers and a proper crossover, probably 10dB.