HifiCompass has done some listening comparisons of the Bliesma domes
Also for the new Bliesma textreme dome
It all comes down to a matter of taste, silk, paper or beryllium. As a long time listener (jazz, acoustic, and electronic) at low volume, after 40 years i still love my silk dome mid range..and my TL sub that gives me deep lows playing low volume. Silk never burned my ears or sounded harsh or unnatural, but that's me! Just discover what you like and build your dream speaker 😉
Silk can be very good, as implicated by the D7608. It depends on many factors, in the end, how the mid will sound character wise. In the pistonic range at average SPLs, there will be little discernable difference between dome materials. The dome profile and thickness can determine some if its transient capabilities. I've heard very detailed sounding cloth domes and some overly smooth veiled one. The D7608 lands in between them. I would venture the M74S would also be in the middle somewhere looking at the specs.
@mikessi The problem with paper diaphragm material is theres a wide range of possible dampening behavior and other physical characteristics based on what's mixed in with it, its density, thickness, rigidity in both planes and the length of its fibers, just to scratch the surface. It can have a wide range of properties, some of which are unpredictable and even un-intentional.
If comparing apples to apples, different formulations of paper should have the common property of higher internal dampening and loss, "typically" being a material consisting of randomly directional stranded fibers.
I haven't heard that many paper dome drivers in my travels. The ones I did come across didn't stick out as being anything special based on my recollections. I can tell you paper or cellulose fiber diaphragms are not so consistent and their acoustical performance are subject to influence by a few atmospheric conditions ie. humidity and temperature being the main ones negatively impacting performance.
Paper can be coated or mixed with other substances greatly changing its acoustical properties. It can be made lighter and thinner than textiles such as silk and linen. Thats a huge potetial advantage.
Both the M74P and S should sound similar to each other based on specs, but I have no direct experience comparing both substances on paper. Rising FR is a good thing, especially when horn loading a driver. The problem with silk is its rigidity, or lack thereof, causing the diaphragm to buckle under higher acoustical load. Paper can be made stiffer, so it has that immediate advantage over cloth or silk.
In the case of other textile diaphragms, these usually perform similarly. They will always have a more veiled sound than solid diaphragms. Paper is usually all over the map, but in lighter weight diaphragm applications it will behave less uniform over its surface, leading to early breakup and other less desirable behavior.
In the case of the D7608, it has an excellent balance of rigidity and dampening. That shows itself as being smoother sounding but more accurate than most other similar large textile mid domes. This mid doesn't suffer from the typical over-dampened sound observed with other larger textile domes.
Judging by the mms of the M74S, it has a lighter variety of silk fiber with less coating. The coating is heavier by volume than the silk itself, but the resulting product should sound livelier than paper, depending on how low the M74P's mms is.
So I'd venture to say the Hificompass review is on point comparing the two M74 versions. I'm just not a fan of the production variances typically encountered with paper or cellulose fiber dome diaphragms. Coated silk would be more predictable and consistent IMO, especially when used in higher power/SPL applications. The upper midrange breakup would be more linear across the entire range. Paper just isn't as well suited to the application unless it's mixed with other fibers or coated with other beneficial materials.
If comparing apples to apples, different formulations of paper should have the common property of higher internal dampening and loss, "typically" being a material consisting of randomly directional stranded fibers.
I haven't heard that many paper dome drivers in my travels. The ones I did come across didn't stick out as being anything special based on my recollections. I can tell you paper or cellulose fiber diaphragms are not so consistent and their acoustical performance are subject to influence by a few atmospheric conditions ie. humidity and temperature being the main ones negatively impacting performance.
Paper can be coated or mixed with other substances greatly changing its acoustical properties. It can be made lighter and thinner than textiles such as silk and linen. Thats a huge potetial advantage.
Both the M74P and S should sound similar to each other based on specs, but I have no direct experience comparing both substances on paper. Rising FR is a good thing, especially when horn loading a driver. The problem with silk is its rigidity, or lack thereof, causing the diaphragm to buckle under higher acoustical load. Paper can be made stiffer, so it has that immediate advantage over cloth or silk.
In the case of other textile diaphragms, these usually perform similarly. They will always have a more veiled sound than solid diaphragms. Paper is usually all over the map, but in lighter weight diaphragm applications it will behave less uniform over its surface, leading to early breakup and other less desirable behavior.
In the case of the D7608, it has an excellent balance of rigidity and dampening. That shows itself as being smoother sounding but more accurate than most other similar large textile mid domes. This mid doesn't suffer from the typical over-dampened sound observed with other larger textile domes.
Judging by the mms of the M74S, it has a lighter variety of silk fiber with less coating. The coating is heavier by volume than the silk itself, but the resulting product should sound livelier than paper, depending on how low the M74P's mms is.
So I'd venture to say the Hificompass review is on point comparing the two M74 versions. I'm just not a fan of the production variances typically encountered with paper or cellulose fiber dome diaphragms. Coated silk would be more predictable and consistent IMO, especially when used in higher power/SPL applications. The upper midrange breakup would be more linear across the entire range. Paper just isn't as well suited to the application unless it's mixed with other fibers or coated with other beneficial materials.
Thanks @mikessi and @profiguy. I really appreciate your time taken to respond and indulge me.
Ultimately, as all my experience thus far tells me, it seems the answers lie in listening. I look forward to doing as much research and learning as i can before the listening begins, there is a lot to consider if one is to achieve a good end result. However, ultimately the best way to decide would be to build two speakers and see which one is preferable.
I see how this rabbit hole adds up!
I will add the M74P, M74S and the D7608 into my considerations.
Going off topic here but these two seem to have more of the properties I might be after
Dayton Apollo 12N https://loudspeakerdatabase.com/Dayton/Apollo_12N
Eighteen Sound 12ND730 https://loudspeakerdatabase.com/18Sound/12ND730
Anyone got any experience with them? Should I start another thread elsewhere perhaps?
Tweeter research required for sure. Can you explain the tapered round over to me? Cabinetry is probably my strongest skill in the process at present so a challenge here isn't shied away from. I understand the taper, being narrower at the top than the bottom, bur the round over?
Many thanks!
Ps i am unsure of etiquette here, if these things are better discussed in private or other threads please do say.
Ultimately, as all my experience thus far tells me, it seems the answers lie in listening. I look forward to doing as much research and learning as i can before the listening begins, there is a lot to consider if one is to achieve a good end result. However, ultimately the best way to decide would be to build two speakers and see which one is preferable.
I see how this rabbit hole adds up!
I will add the M74P, M74S and the D7608 into my considerations.
This makes sense, has sent me off in the direction of understanding what makes a lively and natural sounds woofer. Perhaps it is not the best option.
Going off topic here but these two seem to have more of the properties I might be after
Dayton Apollo 12N https://loudspeakerdatabase.com/Dayton/Apollo_12N
Eighteen Sound 12ND730 https://loudspeakerdatabase.com/18Sound/12ND730
Anyone got any experience with them? Should I start another thread elsewhere perhaps?
Tweeter research required for sure. Can you explain the tapered round over to me? Cabinetry is probably my strongest skill in the process at present so a challenge here isn't shied away from. I understand the taper, being narrower at the top than the bottom, bur the round over?
Many thanks!
Ps i am unsure of etiquette here, if these things are better discussed in private or other threads please do say.
Can't recall where I read this, recently on a thread here, but someone pointed out 2 criteria for a woofer's ability to sound good up into the mid (say 500Hz or higher): high Qms and low Rms. On top of all the other parameters you're seeking. (Maybe in this long thread started by @hifijim about his latest 3-way high end build.) Not certain of the veracity of this assertion but.....
By that criteria, Dayton Apollo 12N is better. OTOH, FaitalPro 12RS430 is much better.
No experience with any of these drivers: some experience with SBA 10" and 12" drivers. I've only ever used them as subs, with LR4 or LR2 filters @ 200Hz or lower.
PS -- If you don't need loud & real deep, the Satori WO24TX (claimed to be 9.5" but looks closer to an 8 than a 10) sounds really good even up ~1500Hz. Subjectively, lively, detailed, transparent. And it will play OK to ~35 Hz. If you go this route, you could always add a sub or 2 if so desired.
Could well be. That discussion starts here: https://www.diyaudio.com/community/...d-on-bliesma-m74a.420575/page-20#post-7909811
Judging by other parameters, the FaitalPro still looks better than the others.
@Kwesi This is solid advice and very applicable to the desired properties an extended range woofer should possess.
@mikessi -
"By that criteria, Dayton Apollo 12N is better. OTOH, FaitalPro 12RS430 is much better."
These two have alot of potential if blended correctly with the baffles influence in mind. The Dayton 12N had me curious when it first came out. They revised this one and the new version is better than before. There is however a significant problem in the 1k area on this driver and I suspect its the spider flopping around at certain frequencies around the wide dip I mentioned.
The SB34NRXL just has a radial surround reflection mode at 800 hz which may be noticeable under certain baffle proportions ie. if diffraction ripple falls within a certain area, either smoothing it out or accentuating it. I've used this driver a few times and have always loved its bass capabilities while performing excellently in the lower mids. I'd definitely describe it as a lively sounding woofer. The demodulation is well thought out and effective. This woofer has the resolution of the larger SS Revalators and can keep up in the excursion department. There is no discernable modulation with the lower mids when this woofer plays loud. That's not an easy feat to accomplish, especially for the cost.
The Satori WO24TX is excellent if you can afford it, but i don't recommend running it past 500 hz. It also needs a notch even if you cross it lower.
The Faital RS woofers have heavy rubber surrounds which cause other problems. Their mid band performance is "ok", but not even close to on par with the Satori 24WOTX or SB34NRXL.
Another good candidate is the Eminence KL3012LF. This is a rare bird of a pro driver that can dig down very low and has a natural midband character. It can be crossed up to 400 hz easily and won't wimp out with big dynamic swings. It also sounds excellent at lower volume. This is a driver you won't have to worry harming grabbing it by the throat and pushing hard. Its well worth the $260 it usually sells for. I use 4 of these, 2 per channel with a large JBL biradial crossed at 800 hz. They will frighten you with their transient capabilities if you aren't prepared. IMO one of the best pro 12" able to perform double duty as an extended mid hifi woofer.
@mikessi -
"By that criteria, Dayton Apollo 12N is better. OTOH, FaitalPro 12RS430 is much better."
These two have alot of potential if blended correctly with the baffles influence in mind. The Dayton 12N had me curious when it first came out. They revised this one and the new version is better than before. There is however a significant problem in the 1k area on this driver and I suspect its the spider flopping around at certain frequencies around the wide dip I mentioned.
The SB34NRXL just has a radial surround reflection mode at 800 hz which may be noticeable under certain baffle proportions ie. if diffraction ripple falls within a certain area, either smoothing it out or accentuating it. I've used this driver a few times and have always loved its bass capabilities while performing excellently in the lower mids. I'd definitely describe it as a lively sounding woofer. The demodulation is well thought out and effective. This woofer has the resolution of the larger SS Revalators and can keep up in the excursion department. There is no discernable modulation with the lower mids when this woofer plays loud. That's not an easy feat to accomplish, especially for the cost.
The Satori WO24TX is excellent if you can afford it, but i don't recommend running it past 500 hz. It also needs a notch even if you cross it lower.
The Faital RS woofers have heavy rubber surrounds which cause other problems. Their mid band performance is "ok", but not even close to on par with the Satori 24WOTX or SB34NRXL.
Another good candidate is the Eminence KL3012LF. This is a rare bird of a pro driver that can dig down very low and has a natural midband character. It can be crossed up to 400 hz easily and won't wimp out with big dynamic swings. It also sounds excellent at lower volume. This is a driver you won't have to worry harming grabbing it by the throat and pushing hard. Its well worth the $260 it usually sells for. I use 4 of these, 2 per channel with a large JBL biradial crossed at 800 hz. They will frighten you with their transient capabilities if you aren't prepared. IMO one of the best pro 12" able to perform double duty as an extended mid hifi woofer.
I also have to add the Silver Flute W20RC38-8 to the list of 8" drivers capable of mating with a 2 - 3" mid dome. This is a driver I discovered sort of by accident. I used it to repair some B&W DM580s with bad woofers. I did a few minor crossover changes to make them blend with the tweeters (which are excellent aluminum domes BTW). The results were nothing short of a shocker. This is a 2.5 way design with the lower woofer running up to 300 hz, but the upper one is crossed at 3.2 k (yes, that's 3200 hz from an 8") and they handle this very well. The only caveat is they need a 3 - 4 dB notch around 4k, which doesn't show any HD peak once filtered out.
The bass was nothing less than excellent for a $50 cast frame woofer without any VC demodulation). The enclosures were rear ported, tuned to 38 hz and the port length didn't need any trimming to get the tuning right.
These woofers are a solid 91 dB/2.83V - 8 ohm version and 93 dB/2.83 - 4 ohm. Build quality is nothing less than impressive for a cheap driver, even if they cost twice what they sell for. The wool blend cone is a little weird but impressively neutral sounding, still being on the warm side.
The bass was nothing less than excellent for a $50 cast frame woofer without any VC demodulation). The enclosures were rear ported, tuned to 38 hz and the port length didn't need any trimming to get the tuning right.
These woofers are a solid 91 dB/2.83V - 8 ohm version and 93 dB/2.83 - 4 ohm. Build quality is nothing less than impressive for a cheap driver, even if they cost twice what they sell for. The wool blend cone is a little weird but impressively neutral sounding, still being on the warm side.
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hi,
this kapa seems to have -F6 at 60 hz only if not choosing a vented design ?! And 9 mm xmax (hard to EQ)
this kapa seems to have -F6 at 60 hz only if not choosing a vented design ?! And 9 mm xmax (hard to EQ)
Really?! I've been working with it as a mid today, running it up to 2000 Hz and hear nothing but high quality repro. I've applied some EQ DSP & crossing to SBA 12" sub drivers at 170Hz LR4 and to various HF drivers LR4 at 1200~2000. By itself, it sounds almost like a full range driver, tho the upper peaks/breakups are clearly audible on axis. Where do you see the need for a notch? I didn't see anything in my sweeps, and see none here: https://audioxpress.com/article/test-bench-sb-acoustics-wo24tx-4-satori-9-5-midbass-woofer
There is some interesting information from the manufacturer about the decisions made when designing the M74P, that is at the bottom of the Hificompass review.
"At that time, I’ve got an idea to make a 3” paper dome midrange, because it was never exist and I was curious how it can sound. Inspired by T25S success, I’ve decide to make a midrange with classical paper warm, sweet and neat sound coloration, which we know from many other good paper cone drivers, but same time it still must follow BlieSMa concept: low Mms, dynamic and not overdamped sound. Finally, this driver should play the music PLEASANT, independent of its measurable parameters.
Together with Dr. Kurt Müller, we developed several paper domes of the different shape and pulp composition, prepared some different coating materials, assembled many different prototypes and started listening tests. Very fast we discovered, that prototypes with ideal frequency response sounding boring. Most of them (despite lower distortion level and high Qms) sounded like a bad copies of beryllium or silk dome versions. Also, we heard the trend between the coloration and combination of the coating, shape and pulp composition.
The task became more alchemy than engineering. Based on this trend, we ordered new shaped domes and new pulp compositions from Dr. Kurt Müller and finally found the best sounding dome. It was non-coated, very thin dome with medium mechanical loses. This experiment showed us, that if paper can’t ever reach neither beryllium clarity and low distortion, nor silk charm, nor AlMg drive – we shouldn’t try to reach these parameters for any price forgetting about the sound. It is much better to highlight this warm and sweet coloration, giving an opportunity to those who like to come home at the end of the day and play their favorite music at the background, enjoying peaceful, colorful and pleasant presentation. It will lie to you, but it is a lies you like to hear.
Now you know, that lower Qms and higher distortion wasn’t neither task nor material limitations but more like a side effect of the sound coloration we liked to achieve from this special product."
I found it to be an intersting enough middle ground between very hard domes and softer domes to get a pair. There is also a pair of T25-B sitting next to them and a pair of 12PR320 drivers in another cupboard waiting for me to find time to build speakers with them.