What about going with a very large wave guide and a coaxial compression driver? you can potentially cross to the bass driver as low as 300Hz and both diaphragms work in their piston regions. Off axis response irregularity's disappear expanding the sweet spot.
B&C Speakers
Overview
B&C Speakers
Overview
I also think that I have not broken in my drivers enough. I will let it play more to see the difference.
Thank you very much. I will really consider those options. The room I show you above has full absorbtion (designed to deal with the lowest room mode @24Hz) and diffusion around the mixing position.
The LF time domain of the room is superb and the system play cleanly down to 20Hz. However, like you said, I still think that if I choose better subwoofer driver instead of Lab 12 I will have even better transient response.
In our lab, we have a pair of Rythmik 12" Aluminum sub, they play extremely tight, but headroom is really limited.
With this 3-way main, I aim for the rooms that use only main monitor without sub. And the critical frequency range that music really need is flat 40-16000. So I aim my 3-way main to play excellent and effortless at that range. The frequency below 40Hz is just a bonus if I have to deal with sub heavy materials like Dub Step or some weird Electronic music/Sound effect.
My studio equipment is also extremely compact. It is only PC + essential devices. Because all of the money I will spend on pro level acoustics and sound system. I believe that is the heart of modern studio, not expensive analog processors. Nowadays, we work totally in-the-box (with digital effects) more often than the past to serve the fast pace of music industry.
Thank you again for introducing to me those beautiful monsters. Those drivers look absolutely brutal and the T/S parameters are also really well suited my needs.
If I cant afford to have them in my next studio, I will try to have them in my personal cave at home.
I have some more questions for you:
1. Why dont Beymar and Precision Devices have demodulation rings in the motor of those drivers?
2. Does demodulation ring really matter in this particular application of mine?
3. Near my house is a big B&C distributor, I have checked B&C 15NDL88 and 15TBX100. They are monsters @@. How do you rate those two 15" B&C midbass drivers to your suggested options?
Thank you and sorry for asking too much.
Thank you for your suggestion. I have thought about using a high quality coax 8in driver from B&C, but after look at their frequency response, I am a little bit scared 🙁 I also dont have experience with really large waveguide. So my decision is to go with normal route until my experience with speaker design becomes many times better than at the moment
Last time I emailed them about a 12" driver for 60-300hz they recommended the 12NDL88 over anything else.
Maybe describe your requirements and see what they recommend. They reply pretty quick....if covid hasn't slowed them down. Factory reopened on the 5th.
Like I mentioned at one point woofers are all pretty good from reputable manufactures. It comes down to what frequency range you need reproduced and how much sound pressure you need. You're best bang for the buck comes from Lavoce(ferrite) and PRV. Lavoce have measured just as good as their B&C counterparts and I will probably replace my 18" B&C's with 21" Lavoce drivers.
Large air displacement and symmetrical suspension/motor force is the name of the game for clean low frequency reproduction. The latest generation of high power/high xmax drivers have been designed with these specifications in mind. B&C, BMS, Precision Devices, Eminence, Faital Pro, RCF, 18 Sound have all had drivers that measured near textbook perfect in these areas. They are all very similar to each other up to a certain spl. All the Italian brands share the same DNA with many of the same designers working for multiple companies in their careers.
Maybe describe your requirements and see what they recommend. They reply pretty quick....if covid hasn't slowed them down. Factory reopened on the 5th.
Like I mentioned at one point woofers are all pretty good from reputable manufactures. It comes down to what frequency range you need reproduced and how much sound pressure you need. You're best bang for the buck comes from Lavoce(ferrite) and PRV. Lavoce have measured just as good as their B&C counterparts and I will probably replace my 18" B&C's with 21" Lavoce drivers.
Large air displacement and symmetrical suspension/motor force is the name of the game for clean low frequency reproduction. The latest generation of high power/high xmax drivers have been designed with these specifications in mind. B&C, BMS, Precision Devices, Eminence, Faital Pro, RCF, 18 Sound have all had drivers that measured near textbook perfect in these areas. They are all very similar to each other up to a certain spl. All the Italian brands share the same DNA with many of the same designers working for multiple companies in their careers.
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I would personally want demodulation rings since you'll be using them up into the low mids while going into the 30's at the same time.
My subjective experience with Eminence, B&C, and BMS woofers is that they all sounded lean at first. I would turn up the volume and wouldn't quite get the punch in the chest/gut I was expecting. Then they would finally loosen up and sound much more effortless in producing tactile bass. Wish I had measurements but I believe I would need a Klippel scanner to really see the difference in measurements.
Check out this monitor using a custom B&C coaxial and what I believe is a 15TBX100(not sure if custom or not).
RM25 Dual 15" Coaxial Reference Monitor | Fulcrum Acoustic
My subjective experience with Eminence, B&C, and BMS woofers is that they all sounded lean at first. I would turn up the volume and wouldn't quite get the punch in the chest/gut I was expecting. Then they would finally loosen up and sound much more effortless in producing tactile bass. Wish I had measurements but I believe I would need a Klippel scanner to really see the difference in measurements.
Check out this monitor using a custom B&C coaxial and what I believe is a 15TBX100(not sure if custom or not).
RM25 Dual 15" Coaxial Reference Monitor | Fulcrum Acoustic
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Thank you for detailed reply. I have calculated the cost of shipping + tax of several suggested Beymar, Lavoce drivers. Unfortunately, they are 1.5-2.5 times than buy B&C, Eminence, Celestion drivers locally, direct from distributors. So in my place, they are not economic choice like other places.
I have looked for 12NDL88 before setled with 12PLB100. The reason I selected 12PLB100 instead of 12NDL88 fpr my 2-way main monitor is the shorting ring. 12PLB100 has one, while 12NDL88 does not.
Luckily, for some reason, B&C put shorting ring on 15NDL88. 15NDL76 has better MMS/BL ratio, however, it is cancelled because it does not have shorting ring. At my place, I can purchase 15NDL88 or 15TBX100 with really good price.
Thank you. Oh my bad 🙁 I thought he mentioned regular coaxial drivers. That kind of coax compression drivers is the first time I see. The one from BMS look absolute awesome piece of work. It is crazily expenssive and way way out of my budget, too. 🙁 But surely, I will watch those kind of drivers and add to my wishlist.
I have a question. I see in the product photo, it has something look like a premade passive crossover attached to the back of driver. Is that included with the driver?
The distortion plot of BMS show really good performance on mid unit, however, I dont understand why H2 H3 on HF unit is so high? Did I missunderstand anything?
Dist curves raised 10db, ask kipman what he thinks about it. I think he have a pair...
I wish I had a pair, I couldn't justify the expense so combined 4*3" drivers and a 1.75" comp onto a horn to get a similar wide bandwidth point source that covers 500 - 20kHz. Details in my signature.
Regular coaxial drivers have historically been quite popular for studio monitors (Urei studio monitors, Altec) but tend to have some no ideal behavior either due to the tweeter->cone transition (flat style) or the woofer output reflecting off the tweeter horn. However I saw some excellent polar measurements of the Vortex 15 drivers.
A lot of harmonic distortion in compression drivers is due to air non linearity so will (broadly) track exit size and SPL at high frequency and not differ by huge amounts between different drivers. I wouldn't worry about it as humans have a high threshold of audibility for harmonic distortion. The BMS data indicates its <10% (probably not noticeable) at 110dB/1m which will be very very loud in a small studio.
Regular coaxial drivers have historically been quite popular for studio monitors (Urei studio monitors, Altec) but tend to have some no ideal behavior either due to the tweeter->cone transition (flat style) or the woofer output reflecting off the tweeter horn. However I saw some excellent polar measurements of the Vortex 15 drivers.
A lot of harmonic distortion in compression drivers is due to air non linearity so will (broadly) track exit size and SPL at high frequency and not differ by huge amounts between different drivers. I wouldn't worry about it as humans have a high threshold of audibility for harmonic distortion. The BMS data indicates its <10% (probably not noticeable) at 110dB/1m which will be very very loud in a small studio.
Thats great, I think I have a clear picture of your performance targets and the room in which you need to achieve these targets... Here are my thoughts and answers to your questions:
(1) Have a good read at this brilliant study, Audio and Loudspeaker Design Guide Lines
Michael is, IMO, a genius. His work as helped me save a lot of time and lots of money in driver selection. Interestingly the drivers that perform best (have the lowest thermal compression and lowest Mms/highest Bl) also perform best in the time domain ie Have less ringing or "bouncing around on their suspensions" after an impulse. So always look for the best CSD plot (waterfall plot) to match the lowest thermal compression.
Precision Devices have the lowest thermal compression of any drivers I have found... Check out this beast PD.1851/2
with just 1.6dB compression at 1KW continuous AES and can handle 6dB peaks of 4KW..! Please note these are Professional AES ratings and not fake"RMS" or audiophile "music power" ratings.
(2) I am not an expert in driver design so I cant answer your question about demodulation rings.
(3) My priorities, in order of importance, when looking at driver spec sheets are:
(a) Never, use a driver with a rubber surround! Only use drivers with linen/cotton surrounds or specialised hybrid fabric/carbon fibre.
(b) Mms / Bl ratio is key ie the lower the moving mass the better and the higher the magnetic force or "grip" to control that moving mass the better. Look for overall "Ref, efficiency" rating in %, not just max dB/SPL rating. Again look at the unique all round brilliance of the PD158 as an example PD.158
(c) Large voice coil, single layer is best. Double layer can handle more power on paper but the thermal compression increases dramatically. Also voice coil/voicecoil former diameter compared to cone diameter. Imagine an 15 inch cone diameter with only a 50mm voice coil attached ie a 50mm cardboard tube glued onto a cone... When that receives 500 watts of piston electrical power to pump it in and out 500 times a second (500 Hz signal) the surface area of contact and the area of cone inside the cardboard tube is tiny... The large cone "flaps" out of phase rapidly. Now imagine the same cone with a 5 inch voice coil / carboard tube attachment... The entire driver cone performance is several orders of magnitude more controlled and stable.
(d) Low Qts, low Qes, low inductance and higher Qms is better.
(e) Xmax. I am not worried by low Xmax at all... See below for more.
(f) Copper voice coils are best, or copper clad aluminium. Kapton voice coil formers are way better than alloy formers.
On Xmax... As a general rule if a driver is using more than 70% of its Xmax at your typical listening levels then use a bigger driver or add second driver to double the Sd and therefor half the driver travel. Always aim for minimum cone travel as a top design priority... Once you have chosen your drivers, use enough of them to keep driver travel as low as possible.
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I have seen their note, too. However, after minus 10dB, the H2 is still 20dB under fundamental. The H3 is really low for a 110dB @1m test.
For coax system, I always prefer 3-way and coax section is on the mid/high drivers crossover. I listened to several 2-way coax speaker before and I dont like them all.
The only coax system I love is Genelec 8351. They sound absolutely awesome. The only downside is... the cost. At that time, they cost ~12.000$/pair shipped 😱
Thank you very much for your valuable advice. It surely will saves a lot of time and money for me, too 😀
Hello,
What happened to this project?
I am looking for a 15" to connect with a 6.5" pa speaker (6md38 B&C), I found this topic interesting. Crossover point 300hz...
If I can't use in wall, I can use wide baffles...I am experimenting that now.
Regarding the low section :
Does QTS matter for home use in a sealed box ?
That said, high bl/MMS ratio will go upper easily but in the lows will require lots of eq, what would be the right balance ?
Reg
What happened to this project?
I am looking for a 15" to connect with a 6.5" pa speaker (6md38 B&C), I found this topic interesting. Crossover point 300hz...
If I can't use in wall, I can use wide baffles...I am experimenting that now.
Regarding the low section :
Does QTS matter for home use in a sealed box ?
That said, high bl/MMS ratio will go upper easily but in the lows will require lots of eq, what would be the right balance ?
Reg