Hi experts,
I'd like to put my thought or plan or whatever to get experts' advices on it.
I have been thinking of a new 3-way speakers around the same ATC SCM75-150s, complemented with Scanspeak D2104 21mm tweeters and some 8" double woofer instead of a 10" Volt B2500.1.
Then I was invited by another DIYer for auditioning his new speakers using Raal 70-20 tweeters, Scanspeak's freakin' expensive 83mm dome midrange, also Scanspeak's illuminator 7" as a midbass, along with Scanspeak's 13" woofer. He originally planned a 3-way without the midbass, but got an advice from a professional to add the midbass in between. It sounded awesome, and also seem to prove the superiority of the 4-way design.
So, I began to wonder what if I add midbass between ATC and 8" double woofers. My logical half tells me professionals and experts will say midbass is not necessary with 8" double woofer below. But I am still curious. What are your thoughts about this?
Regards,
Jay
I'd like to put my thought or plan or whatever to get experts' advices on it.
I have been thinking of a new 3-way speakers around the same ATC SCM75-150s, complemented with Scanspeak D2104 21mm tweeters and some 8" double woofer instead of a 10" Volt B2500.1.
Then I was invited by another DIYer for auditioning his new speakers using Raal 70-20 tweeters, Scanspeak's freakin' expensive 83mm dome midrange, also Scanspeak's illuminator 7" as a midbass, along with Scanspeak's 13" woofer. He originally planned a 3-way without the midbass, but got an advice from a professional to add the midbass in between. It sounded awesome, and also seem to prove the superiority of the 4-way design.
So, I began to wonder what if I add midbass between ATC and 8" double woofers. My logical half tells me professionals and experts will say midbass is not necessary with 8" double woofer below. But I am still curious. What are your thoughts about this?
Regards,
Jay
Mid bass makes more sense for detail
With very heavy duty sub woofers.
Since they dont have much detail above 80 to 100 Hz
Very high inductance / large diameter coils
I dont mind passive crossovers at all.
But " sub woofers" make more sense
for active because of size of coils is costly.
Likewise excursion protection filters
make more sense active
because impedance curve is a roller coaster
down there
With very heavy duty sub woofers.
Since they dont have much detail above 80 to 100 Hz
Very high inductance / large diameter coils
I dont mind passive crossovers at all.
But " sub woofers" make more sense
for active because of size of coils is costly.
Likewise excursion protection filters
make more sense active
because impedance curve is a roller coaster
down there
If you use subs with a crossover at 60-80 Hz, a tweeter like a ribbon with a limited low frequency at 3-6 kHz, a small 3" midrange with limited low frequency extension, or similar the passband of a single midrange becomes greater than a decade and the response will be compromised to some degree at the high and/or low end. A 4 way tends to become a better choice. A decade can also be asking a bit much if one opts for pistonic hard coned drivers and want to avoid the harmonics of the motor driving the resonances. With a 3" (upper) midrange driver there is a case for a lower midrange driver and subs.
On the other hand if you start with 2 x 8" woofers then a 3 way with 4-5" midrange and 1" tweeter with lower crossover frequencies works well. It depends on what you want to fix in the spec and what you can adjust to optimize performance.
My vote goes for a 4 way over a three way if you are building and "end game" system and want the best, but if its a "learning curve" build you plan on selling later then go for a three way.
Regardless of 3 or 4 way, here are my top ten tips:
(1) Active crossover is a must, preferably modern DSP based but if you are a pure analog fan then a good analog active crossover is still way better than a passive crossover.
(2) 3 or 4 channels of amplification is required per cabinet, but there are a lot of low cost high quality power amps available and you can mis valves up top with solid state low down for the best of all worlds.
(3) Sealed box or open baffle will consistently outperform any ported/passive radiator/transmission line delayed resonance system. Also far more flexible with cabinet volume and driver specification tolerance.
(4) Choose dedicated Pro drivers rather than audiophile drivers, this will increase performance and decrease $ costs.
(5) When studying driver spec sheets, prioritise the Time Domain performance over the frequency domain! Always study the "Cumulative Spectral Decay" (waterfall plots) and choose drivers ability which to not store energy (the shortest time taken to settle back to zero dB) in the frequency band you will be using the driver. A "clean" is a great indicator of a well designed driver.
(6) Never use drivers with big rubber surrounds, always choose the cotton/linen/silk/fabric surrounds used in Pro drivers.
(7) Size matters... Try to use the largest Sd you can to cover any given frequency band, this can be one large driver or multiple smaller drivers.
(8) Sensitivity is king. Look for the drivers rated "Reference Efficiency" in the spec sheet (not just the rated sensitivity) as a higher efficiency will minimise the amount of cone travel required to reach your max SPL in your room. My rule is no driver should ever exceed 50% of its rated Xmax at your chosen peak SPL's and typically under 20% at your average levels.
(9) Second priority is power handling, using your chosen max SPL's, try not to exceed 40% to 50% of max continuous AES rating, ignore the audiophile manufacturer claims in RMS or "recommended power handling" BS!
(10) Use separate cabinets for each driver "way".
(11) Heavy cabinets are important, even in open baffle! My rule of thumb is minimum for the ratio of cabinet weight to driver cone weight (Mms) is 500 to 1. ie if your mid bass Mms is 100g the cabinet should weigh 50Kg. You can compromise a bit on this but remember the driver prob weighs around 12Kg so adding another 35Kg for the cabinet is not too extreme. Stranded bamboo is great but expensive and cheap steel plate is better than Magico's expensive alloy! Never ever use any MDF!
(12) If you have room to pull the cabinets out 1m or so from the front wall open baffle is best for mid bass, mid and top end. Low bass (20Hz to around 70Hz) can be sealed of open baffle... Sealed if the system is part of a home cinema or open baffle if its music only. Either choice will sound superb if you choose DSP / Eq crossover, open baffle is easier to integrate with most rooms if you choose analog active crossover.
Oops, ran over to 12 tips... Hope some of them help!
Cheers
A.
Regardless of 3 or 4 way, here are my top ten tips:
(1) Active crossover is a must, preferably modern DSP based but if you are a pure analog fan then a good analog active crossover is still way better than a passive crossover.
(2) 3 or 4 channels of amplification is required per cabinet, but there are a lot of low cost high quality power amps available and you can mis valves up top with solid state low down for the best of all worlds.
(3) Sealed box or open baffle will consistently outperform any ported/passive radiator/transmission line delayed resonance system. Also far more flexible with cabinet volume and driver specification tolerance.
(4) Choose dedicated Pro drivers rather than audiophile drivers, this will increase performance and decrease $ costs.
(5) When studying driver spec sheets, prioritise the Time Domain performance over the frequency domain! Always study the "Cumulative Spectral Decay" (waterfall plots) and choose drivers ability which to not store energy (the shortest time taken to settle back to zero dB) in the frequency band you will be using the driver. A "clean" is a great indicator of a well designed driver.
(6) Never use drivers with big rubber surrounds, always choose the cotton/linen/silk/fabric surrounds used in Pro drivers.
(7) Size matters... Try to use the largest Sd you can to cover any given frequency band, this can be one large driver or multiple smaller drivers.
(8) Sensitivity is king. Look for the drivers rated "Reference Efficiency" in the spec sheet (not just the rated sensitivity) as a higher efficiency will minimise the amount of cone travel required to reach your max SPL in your room. My rule is no driver should ever exceed 50% of its rated Xmax at your chosen peak SPL's and typically under 20% at your average levels.
(9) Second priority is power handling, using your chosen max SPL's, try not to exceed 40% to 50% of max continuous AES rating, ignore the audiophile manufacturer claims in RMS or "recommended power handling" BS!
(10) Use separate cabinets for each driver "way".
(11) Heavy cabinets are important, even in open baffle! My rule of thumb is minimum for the ratio of cabinet weight to driver cone weight (Mms) is 500 to 1. ie if your mid bass Mms is 100g the cabinet should weigh 50Kg. You can compromise a bit on this but remember the driver prob weighs around 12Kg so adding another 35Kg for the cabinet is not too extreme. Stranded bamboo is great but expensive and cheap steel plate is better than Magico's expensive alloy! Never ever use any MDF!
(12) If you have room to pull the cabinets out 1m or so from the front wall open baffle is best for mid bass, mid and top end. Low bass (20Hz to around 70Hz) can be sealed of open baffle... Sealed if the system is part of a home cinema or open baffle if its music only. Either choice will sound superb if you choose DSP / Eq crossover, open baffle is easier to integrate with most rooms if you choose analog active crossover.
Oops, ran over to 12 tips... Hope some of them help!
Cheers
A.
It depends on what is valued in a speaker. Here in the UK there is a history of speaker diy kits using extremely expensive drivers from the likes of atc, volt, scan-speak with basic cabinets and basic crossovers. As best I can judge from posts on local audio forums many purchasers are happy and keep the speakers for a long time. They don't seem to be speaker DIY hobbyists though but more subjective home audio enthusiasts looking for a prestige end game speaker that isn't the price of commercial subjective audiophile end game speakers.
Hi WhiteDragon. Thank you for your reply. Sorry that I forgot to mention I have an SVS SB13 Ultra sub, so that's why I am going with 2 smaller woofers than before. Hopefully, there is no issue with SB13 Ultra + 2 8" woofers in the low bass.
Hi Hydrogen Alex,
Thank you very much for your tips. Since there are so many, I am making my comments embedded below:
My vote goes for a 4 way over a three way if you are building and "end game" system and want the best, but if its a "learning curve" build you plan on selling later then go for a three way.
JH> This is encouraging, though I might want to build more after this. I had a pretty successful 3-way design, though I didn't build the enclosures myself.
Regardless of 3 or 4 way, here are my top ten tips:
(1) Active crossover is a must, preferably modern DSP based but if you are a pure analog fan then a good analog active crossover is still way better than a passive crossover.
JH> Exactly, though my local peers don't agree. I am using a modified surround processor to accommodate steep linear-phase FIR crossover, and will build a Mac-based electronics system using professional gears for more flexibility.
(2) 3 or 4 channels of amplification is required per cabinet, but there are a lot of low cost high quality power amps available and you can mis valves up top with solid state low down for the best of all worlds.
JH> Absolutely. It would be a great fun to think about what amplifiers to match what drivers. Call me crazy, but I am using a Prima Luna tube amplifiers for 2 ATC midranges, though tweeters and woofers are driven by solid state amps. I will continue using Prima Luna for the midranges, and probably Job 225 stereo amplifier for tweeters. Might use some stereo amps for midbass and woofers instead of the current 9-ch HT amplifier.
(3) Sealed box or open baffle will consistently outperform any ported/passive radiator/transmission line delayed resonance system. Also far more flexible with cabinet volume and driver specification tolerance.
JH> That's also a great idea. Sealed for midbass for sure, and also sealed for 2 8" woofers, thanks to the subwoofer. My current one is ported for the 10" woofer, but I feel that it's working suboptimally and kind of redundancy, combined with the 13" sealed sub.
(4) Choose dedicated Pro drivers rather than audiophile drivers, this will increase performance and decrease $ costs.
JH> I guess SCM75-150 falls in the pro driver category. I don't know about midbass/woofer surely for now, but was thinking Scanspeak ones mainly. What would you recommend for tweeter/midbass/woofers? I think I would go with D2104 because my old D2904/9500 doesn't seem good enough in dispersion.
(5) When studying driver spec sheets, prioritise the Time Domain performance over the frequency domain! Always study the "Cumulative Spectral Decay" (waterfall plots) and choose drivers ability which to not store energy (the shortest time taken to settle back to zero dB) in the frequency band you will be using the driver. A "clean" is a great indicator of a well designed driver.
JH> I will try to learn how to look at the waterfall diagrams. Honestly, I didn't pay much attention.
(6) Never use drivers with big rubber surrounds, always choose the cotton/linen/silk/fabric surrounds used in Pro drivers.
JH> Is this due to the efficiency? I find those surround materials scarce in the drivers of renowned audiophile high-end manufacturers. It's also hard to evaluate(or audition) good professional monitor speakers.
(7) Size matters... Try to use the largest Sd you can to cover any given frequency band, this can be one large driver or multiple smaller drivers.
JH> Do you see problems with my choice of 21mm + 75mm + 7" + 8" x2?
(8) Sensitivity is king. Look for the drivers rated "Reference Efficiency" in the spec sheet (not just the rated sensitivity) as a higher efficiency will minimise the amount of cone travel required to reach your max SPL in your room. My rule is no driver should ever exceed 50% of its rated Xmax at your chosen peak SPL's and typically under 20% at your average levels.
(9) Second priority is power handling, using your chosen max SPL's, try not to exceed 40% to 50% of max continuous AES rating, ignore the audiophile manufacturer claims in RMS or "recommended power handling" BS!
JH> I think my criteria is in line with yours, here. Do scanspeak 7/8" woofers qualify?
(10) Use separate cabinets for each driver "way".
JH> Do you mean modular individual enclosures? That's what I am dreaming of at this time. If yes, how would you mechanically combine them against vibration and slight drift from one another if just placed on top of another?
(11) Heavy cabinets are important, even in open baffle! My rule of thumb is minimum for the ratio of cabinet weight to driver cone weight (Mms) is 500 to 1. ie if your mid bass Mms is 100g the cabinet should weigh 50Kg. You can compromise a bit on this but remember the driver prob weighs around 12Kg so adding another 35Kg for the cabinet is not too extreme. Stranded bamboo is great but expensive and cheap steel plate is better than Magico's expensive alloy! Never ever use any MDF!
JH> I'd agree for the sound, but I am somewhat burned with heavy stuffs. My current speaker is about 60Kg. I will have to think about it. How about HDF?
(12) If you have room to pull the cabinets out 1m or so from the front wall open baffle is best for mid bass, mid and top end. Low bass (20Hz to around 70Hz) can be sealed of open baffle... Sealed if the system is part of a home cinema or open baffle if its music only. Either choice will sound superb if you choose DSP / Eq crossover, open baffle is easier to integrate with most rooms if you choose analog active crossover.
JH> I am afraid dipoles are hard to make behave. I am also kind of space-limited(WAF). I saw my friend's Magnepans behaving very weirdly. I'd go with safe box styles, and my midrange planned has its own chamber already, not to mention the tweeters, so having only midbass dipole doesn't seem to make sense.
Thank you very much for your tips. Since there are so many, I am making my comments embedded below:
My vote goes for a 4 way over a three way if you are building and "end game" system and want the best, but if its a "learning curve" build you plan on selling later then go for a three way.
JH> This is encouraging, though I might want to build more after this. I had a pretty successful 3-way design, though I didn't build the enclosures myself.
Regardless of 3 or 4 way, here are my top ten tips:
(1) Active crossover is a must, preferably modern DSP based but if you are a pure analog fan then a good analog active crossover is still way better than a passive crossover.
JH> Exactly, though my local peers don't agree. I am using a modified surround processor to accommodate steep linear-phase FIR crossover, and will build a Mac-based electronics system using professional gears for more flexibility.
(2) 3 or 4 channels of amplification is required per cabinet, but there are a lot of low cost high quality power amps available and you can mis valves up top with solid state low down for the best of all worlds.
JH> Absolutely. It would be a great fun to think about what amplifiers to match what drivers. Call me crazy, but I am using a Prima Luna tube amplifiers for 2 ATC midranges, though tweeters and woofers are driven by solid state amps. I will continue using Prima Luna for the midranges, and probably Job 225 stereo amplifier for tweeters. Might use some stereo amps for midbass and woofers instead of the current 9-ch HT amplifier.
(3) Sealed box or open baffle will consistently outperform any ported/passive radiator/transmission line delayed resonance system. Also far more flexible with cabinet volume and driver specification tolerance.
JH> That's also a great idea. Sealed for midbass for sure, and also sealed for 2 8" woofers, thanks to the subwoofer. My current one is ported for the 10" woofer, but I feel that it's working suboptimally and kind of redundancy, combined with the 13" sealed sub.
(4) Choose dedicated Pro drivers rather than audiophile drivers, this will increase performance and decrease $ costs.
JH> I guess SCM75-150 falls in the pro driver category. I don't know about midbass/woofer surely for now, but was thinking Scanspeak ones mainly. What would you recommend for tweeter/midbass/woofers? I think I would go with D2104 because my old D2904/9500 doesn't seem good enough in dispersion.
(5) When studying driver spec sheets, prioritise the Time Domain performance over the frequency domain! Always study the "Cumulative Spectral Decay" (waterfall plots) and choose drivers ability which to not store energy (the shortest time taken to settle back to zero dB) in the frequency band you will be using the driver. A "clean" is a great indicator of a well designed driver.
JH> I will try to learn how to look at the waterfall diagrams. Honestly, I didn't pay much attention.
(6) Never use drivers with big rubber surrounds, always choose the cotton/linen/silk/fabric surrounds used in Pro drivers.
JH> Is this due to the efficiency? I find those surround materials scarce in the drivers of renowned audiophile high-end manufacturers. It's also hard to evaluate(or audition) good professional monitor speakers.
(7) Size matters... Try to use the largest Sd you can to cover any given frequency band, this can be one large driver or multiple smaller drivers.
JH> Do you see problems with my choice of 21mm + 75mm + 7" + 8" x2?
(8) Sensitivity is king. Look for the drivers rated "Reference Efficiency" in the spec sheet (not just the rated sensitivity) as a higher efficiency will minimise the amount of cone travel required to reach your max SPL in your room. My rule is no driver should ever exceed 50% of its rated Xmax at your chosen peak SPL's and typically under 20% at your average levels.
(9) Second priority is power handling, using your chosen max SPL's, try not to exceed 40% to 50% of max continuous AES rating, ignore the audiophile manufacturer claims in RMS or "recommended power handling" BS!
JH> I think my criteria is in line with yours, here. Do scanspeak 7/8" woofers qualify?
(10) Use separate cabinets for each driver "way".
JH> Do you mean modular individual enclosures? That's what I am dreaming of at this time. If yes, how would you mechanically combine them against vibration and slight drift from one another if just placed on top of another?
(11) Heavy cabinets are important, even in open baffle! My rule of thumb is minimum for the ratio of cabinet weight to driver cone weight (Mms) is 500 to 1. ie if your mid bass Mms is 100g the cabinet should weigh 50Kg. You can compromise a bit on this but remember the driver prob weighs around 12Kg so adding another 35Kg for the cabinet is not too extreme. Stranded bamboo is great but expensive and cheap steel plate is better than Magico's expensive alloy! Never ever use any MDF!
JH> I'd agree for the sound, but I am somewhat burned with heavy stuffs. My current speaker is about 60Kg. I will have to think about it. How about HDF?
(12) If you have room to pull the cabinets out 1m or so from the front wall open baffle is best for mid bass, mid and top end. Low bass (20Hz to around 70Hz) can be sealed of open baffle... Sealed if the system is part of a home cinema or open baffle if its music only. Either choice will sound superb if you choose DSP / Eq crossover, open baffle is easier to integrate with most rooms if you choose analog active crossover.
JH> I am afraid dipoles are hard to make behave. I am also kind of space-limited(WAF). I saw my friend's Magnepans behaving very weirdly. I'd go with safe box styles, and my midrange planned has its own chamber already, not to mention the tweeters, so having only midbass dipole doesn't seem to make sense.
Hi Andy,
That's exactly what I did though I had the box built by the kit maker, and I live in SoCal. My current one is almost 20-years old, serving me very well. I only do S/W DIY, as my hand skills suck.
. I now want to go one or two notches higher, but not as crazy as my friend who used Raal, $2800 Scanspeak dome mid and the 13" woofers.
Thank you for your detailed advice. I am going to use ATC SCM75-150(very well proven) or maybe Volt VM752/753 if I have a problem in procuring the ATCs. They cover 380/500 ~ 3800Hz. I think these mids will blend well with almost any tweeter with great flexibility in choosing crossover frequencies. 3800Hz for mid/tweeter worked well, as recommended by ATC. I want to exploit this high crossover frequency and use 21mm tweeter instead of 1" range for better dispersion.
380Hz for the woofer with the ATC mid seems to work well, too, though I don't know what people who don't know or like ATC mids think about this low ccrossover for a small(er than cones) dome driver. Does this make good sense?
Please tell us about the cross over that was used . The frequencies , order etc.
Regards,
Anwesh
Those drivers are different from the ATC you will find less xmax, and a higher fs around 450h,
Z, vs the ATC's 300 ish.
As for tweeter the dome shape might make more difference then the 21mm vs 1" actually.
Hi Anwesh,
I am using some linear-phase FIR design of different orders for mid/tweeter and mid/woofer. If I recall correctly, about 400 taps for mid/woofer and about 200 taps for mid/tweeter. The length and latency difference between 2 filters are properly compensated for time alignment. The slope is greater than 110dB/oct, but both filtered parts sum up correctly like, or better than LR4. 6dB points are around 380Hz and 3800Hz.
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Those drivers are different from the ATC you will find less xmax, and a higher fs around 450h,
Z, vs the ATC's 300 ish.
As for tweeter the dome shape might make more difference then the 21mm vs 1" actually.
-----
Hi Arez,
Thank you for your comments. I had spotted differences after I bought Wilmslow Topline Centre. That's why I prefer ATC to Volt's.
For the tweeter dome shapes, do you find a better ones with better shape and larger diameter than Scanspeak D2104/71200? Please let me know your recommendations. For now, I am not looking at the hard domes like metal, ceramic, diamond, etc.
Z, vs the ATC's 300 ish.
As for tweeter the dome shape might make more difference then the 21mm vs 1" actually.
-----
Hi Arez,
Thank you for your comments. I had spotted differences after I bought Wilmslow Topline Centre. That's why I prefer ATC to Volt's.
For the tweeter dome shapes, do you find a better ones with better shape and larger diameter than Scanspeak D2104/71200? Please let me know your recommendations. For now, I am not looking at the hard domes like metal, ceramic, diamond, etc.
I'd advice you to study different tweeters, measurements and off axis curves.
You will find that the dispersion is not reliant on diameter alone is all.
Look at the attached ones below from Hificompass.
You can see the 1" T25 (with al/mg diaphragm though), has a wider dispersion and better behaved off axis all the way up, vs the 2104.
Attachments
@jheoaustin - If I understand correctly, the only driver you have chosen is a 3" dome midrange, from either ATC or Volt. Everything else about the design is undecided. Is this correct?
What are your thoughts about total cabinet size? Do you have separate subwoofer(s), or do you want this system to be truly full range without subs?
It is not clear if you are planning this system to be active with DSP filtering, or passive... ?
Thanks.
What are your thoughts about total cabinet size? Do you have separate subwoofer(s), or do you want this system to be truly full range without subs?
It is not clear if you are planning this system to be active with DSP filtering, or passive... ?
Thanks.
It can be hard to give constructive advice when one is following enthusiasms rather than dry engineering (which is of course a perfectly reasonable thing to be doing with a hobby!). ATC stopped supplying their small soft domed midrange to other manufacturers and the DIY market a few years back so it will be difficult to obtain a pair and, depending on how obtained, ATC may not support them. The Volt drivers seem to be a small step down in performance and are a ludicrous price. If one really wants to use a small 3" soft dome the Neumann neo one seems to offer the same level of performance as the ATC it replaced but in a more usable package. Mind you I have not seen it used in DIY projects so it may be just as difficult to obtain as the ATC for DIYers. It's not something I have looked into. Anyone?
It might work after a fashion but it won't be working well at the low frequency end compared to a more appropriately sized midrange. To work well it likely needs a larger waveguide and a higher crossover frequency to the woofers (or lower midrange + woofers). It also flaps a bit at high frequencies and so will likely benefit from a lower crossover frequency to a 1" tweeter in a waveguide. That is, more like how K&H used to use it rather than ATC.
A small tweeter gives wider dispersion not better dispersion. Better dispersion in a technical sense is more like smoothly controlling the variation in beam width with frequency to get as close as possible to a neutral timbre in use in a room. Of course better dispersion in an audiophile sense may, quite reasonably, mean whatever sounds good to me which may well be a rapid move to wide dispersion at high frequencies.
A soft 3" midrange driver can be made to work well but there are as good if not better and cheaper approaches which is why they have become rare these days. So if your objective is to design a speaker that uses an ATC/Volt 3" soft dome then yes that makes sense. If your objective is to design a high performance speaker then preselecting an ATC/Volt 3" soft dome driver (or any driver for that matter) makes less sense.
Thank you very much for sharing your design plan. It is a very serious project to say the least, and I admit that it's very different from usual things in my DIY world.
BTW, I don't have a lot of drivers, though a Mac would account for dozens of audio DSPs. Looking forward to yours' completion and start of mine.