3 way active with real punch.. which way would you go.? Pro driver or .?

[DWPress]

What you're hoping to do is something I've been evolving for 30 years starting with passive components and 10+ with digital XO starting with a Minidsp 4x10 to do XO, time, EQ and SPL corrections to the diverse drivers involved in a 3-way XO + subs. FYI, Minidsp hardware Sharc processors are pretty limited with what you can do in bass frequencies and the basic Dirac they offer is also pretty crappy by comparison. I do it all via computer now which allows far greater flexibility.

I built these HUGE monkey coffins based on the "golden mean" dimensions in all the speaker building books back in the 80's following all the T/S guidance available at the time and they are dimensionally huge sealed enclosures (I'm committed, 180 liter, 6.4 cubic foot) to adequately cover the frequency range of 30-20kHz I was hoping for. In retrospect, in futility. The enclosures have remained huge but have undergone massive internal changes over the years as well as speaker drivers as I learned better practices, gained access to better software tools and trying to understand half of what some of the really smart people here know.

I know you're looking at 80-120Hz zone but if you want to activate the room and reinforce the presence in that frequency range get some subs. I'm in a 16x20x11', 3500 cubic foot space and XO my 15" woofers to two subs at 65Hz because it works better in MY space and speaker placement.

My goal has been to have an even sound throughout the room (it's my art studio, I move around) instead of a specific listening position so have added some absorption and diffusion for my specific needs.

Some things not mentioned often enough when going active. Sorry if obvious but I learned the hard way.

• Pay specific attention to the sensitivity of your W/M/T combination with the intent in advance that you're applying EQ and DSP which will automatically reduce your overall SPL.
• Also, very important, the input sensitivity and voltage gain for the amps you want to use for each driver speaker pair. No use really having a stellar SINAD for your tweeter amp if it only has 13dB of gain and now you have to pad down your 89dB sensitivity woofer to get to your 94 SPL/w/m tweeter audible.
• With larger midrange drivers (5" +) they start to beam at lower frequencies off axis. Be aware of this depending on the directivity you are hoping to achieve with your build.
• Impedance of driver selections in harmony with each other and the amplifiers that are driving them - voltage limited vs power limited.

Current configuration of drivers to fill in what's not in the sig:
GRS 15PT8 15" woofers
B&C 6md38 6.5" midrange
Audax two34xo 1.25" dome tweeters
15" Dayton rss390hf-4 sub + a SVS 12" SB1000 in opposite corners (not ideal but necessary)

currently using LR4 XO at 65, 350, 1500kHz but one of the subs uses a gentler slope on the HP because it integrates better somehow with MY room in SPL and phase.

Good luck! Have fun! I know you will, I have. It will, eventually, sound awesome!

 

[Audionaut]

Just take a look at BMS

Or
RCF, B&C, 18sound, Faital Pro, Beyma, Precision Devices, Oberton and Celestion
I think you will find suitable chassis in every portfolio of the renowned PA companies.

I once installed this 12S305 from BMS in an active three-way system. Very good chassis

Overview

www.bmsspeakers.com

 

[Heinrich]

With high spl DSP active with real punch/slam being out of my $ range it seems DIY active would be for this sorta thing would be the way to go. Top flight Pro bass drivers in 15" range seem like a way to go, but so does the 13" Scan Speak.? B & C & Beyma have some nice upper end drivers, so do many others. If you were to do a 15"dsp active 3way with high spl capability & above all 80-100hz ish pinch/slam that is felt at 9-10' which way would you go.? Been so long since I had anything close to it I forgot what it really takes. Not interested in small multi driver towers at all.

Fun fact with p/a, those guys judge the effort by its outcome, not the input. Home hifi looks more at the input, what gets in to a ‚system‘, which brand, what driver size, the material of cone and dome, cable isolation (really!?) … as I said, fun fact.

Of course you are on the pro side. A single well implemented 12“ per side at a distance of 3m / 10’ will for sure knock your socks off. You will not be able to run into any compression or other sorts of limitation without secretly admitting that the spl is WAY to high to be remotely pleasant by any means. It‘s a blanket statement, but it holds.

Look, the overall loudness is the contribution of all the frequencies combined. Even with bass heavy music the bigger part, subjectively, comes from the mids. Too loud of a bass will will soon feel like having a deep dive under water, that pressure, permanently. The mids will simply hurt and deafen you - for days after the fact.

Still the 12“ will grin at you asking for more. As said before:
a) because it will remain virtually free of distortion, you won‘t be able to sense its limits anyway
b) a 15“ would scale up by only 3dB, which is nil in this context
c) German BMS, US JBL are premium, don‘t waste your time and money on cheap contenders for too many evaluation runs; the industry can afford this, not you
d) 60 liters, port tuning to 35Hz, 10..15cm port diameter (wind noises!! limit performance the most today) and you‘re done, leave rest to room equalization; go active with a crossover at 250Hz or lower

cheers

 

[Jaxjax]

The ATC SCM 150 SL is a dream speaker for me or the 100 for that matter & would like to copy at least the aesthetics of them . I Can them change the front baffle out for different configurations, drivers etc. I was to try a coax but not sure if I should go that route with my skill set. Width of speaker IS heavily in the equation because I can only go so far left with left speaker as it's in a corner, but ATC 150 or 100 dimensions would be ok. The B & C SW115 or Faital 15HP1060 etc, with maybe Purifi 6.5" @ 93.2 db & a decent tweet I can cross low. I have some Scan Speak 9500 already but I'm sure I'll need better. I also think I should try strong BL on the 15-12" .? I could also try the 3" Volt at 94db, but don't know if still available. I do have the Yamaha P2500S so will start with those. Will research computer solutions vs minidsp flex 8 for a start.

 

[Heinrich]

The ATC SCM 150 SL is a dream speaker for me or the 100 for that matter & would like to copy at least the aesthetics of them . I Can them change the front baffle out for different configurations, drivers etc. I was to try a coax but not sure if I should go that route with my skill set. Width of speaker IS heavily in the equation because I can only go so far left with left speaker as it's in a corner, but ATC 150 or 100 dimensions would be ok. The B & C SW115 or Faital 15HP1060 etc, with maybe Purifi 6.5" @ 93.2 db & a decent tweet I can cross low. I have some Scan Speak 9500 already but I'm sure I'll need better. I also think I should try strong BL on the 15-12" .? I could also try the 3" Volt at 94db, but don't know if still available. I do have the Yamaha P2500S so will start with those. Will research computer solutions vs minidsp flex 8 for a start.

Sorry, won‘t do, and why shall it, to begin with. One ingredient of the secret sauce is the midrange. Its small dimension, allowing for a smaller center to center distance to the tweeter. And for sure there are many more.

In case you need ‚for sure better‘ than the Scan Speak mentioned, that is beyond my horizon.

Good luck!

 

[Audionaut]

The ATC SCM 150 SL is a dream speaker for me

A concept that I consider difficult in terms of the consistency of sound dispersion: A 15 inch bass speaker that should have high efficiency and needs to be separated relatively high because of the ATC SM75SU dome, which firstly radiates wide and secondly, even if it can be coupled low, can never be decoupled as low as a high power compression driver or a cone chassis.
This will result in a very wavy behavior of the vertical and horizontal isobars and a mediocre lower cut-off frequency for such a large speaker.
Many things can be equalized actively, but a 15 inch bass loudspeaker that is also supposed to reproduce the mid-range cleanly should not be equalized too much actively, because otherwise the mid-range will become measurably unclean.
This is very difficult to do yourself, also because the ATC dome tweeter is no longer available individually on the open market and all other domes, including the Bliesma domes, have a different dispersion behavior.

 

[Jaxjax]

A concept that I consider difficult in terms of the consistency of sound dispersion: A 15 inch bass speaker that should have high efficiency and needs to be separated relatively high because of the ATC SM75SU dome, which firstly radiates wide and secondly, even if it can be coupled low, can never be decoupled as low as a high power compression driver or a cone chassis.
This will result in a very wavy behavior of the vertical and horizontal isobars and a mediocre lower cut-off frequency for such a large speaker.
Many things can be equalized actively, but a 15 inch bass loudspeaker that is also supposed to reproduce the mid-range cleanly should not be equalized too much actively, because otherwise the mid-range will become measurably unclean.
This is very difficult to do yourself, also because the ATC dome tweeter is no longer available individually on the open market and all other domes, including the Bliesma domes, have a different dispersion behavior.

How about the Purify PTT6.5M ? There is the the Purifi 5.25 & 4.5 mids but those to are like 85db vs the 93.2db of the PTT6.5..
the 9500's I have are 550 @ 91.. Could go the SS D2404/5520-00 route but there$ 500. a pop. Same Fs & 91db but nice off axis. I'll model plug some of these in & see how screw'd I am
I also see the SS D3004/5520-00 is 97db @ Fs 475 ... & a few other SS that are 94.5db around 500 Fs
The SCM150 ASL box is OD of 8.84 cuft. so 8 cu internal maybe.?

 

[Audionaut]

These aren't beauties, but they were some of the best speakers I've made.
18-inch bass, AMT tweeters, all Beyma components, external activation via the DCX2496 and PA multi-channel amplifier.
I think they could do everything you asked for here.

 

[JohnnyNG]

View attachment 444287

These aren't beauties, but they were some of the best speakers I've made.
18-inch bass, AMT tweeters, all Beyma components, external activation via the DCX2496 and PA multi-channel amplifier.
I think they could do everything you asked for here.

I disagree, they're beauties!

 

[DWPress]

The SCM150 ASL box is OD of 8.84 cuft. so 8 cu internal maybe.?

@Audionaut - they look good to me!

Again, speaking from experience, 8 cu feet is the size of a refrigerator. Are you settled with a home and don't plan to move? If you are settled and have a specific room they will live in - then design your speaker for the room!

Having really large enclosures with capable drivers is incredible but seriously consider the trade offs. I fly mine from the ceiling so they don't take up valuable floor space but this isn't ideal either. Optics fail, consider the size of these compared to the standard 32" doors.

 

[crazycloud]

These aren't beauties, but they were some of the best speakers I've made.
18-inch bass, AMT tweeters, all Beyma components, external activation via the DCX2496 and PA multi-channel amplifier.
I think they could do everything you asked for here.

I agree with @JohnnyNG that they're lovely. Not fancy like a SF perhaps, but functionally elegant. Out of curiosity, what are the cone Beymas you used?

Over 20ya I made a similar speaker with JBL 2226/2123/ Beyma CP380M and some old Yamaha horns (about the same size as Altec 811), all active. Originally it was a custom designed analog xover, later DSP when they became affordably available. There were many later versions with a variety of different drivers.

I later went to MEHs, that were 2x the size of yours and in plain MDF until I moved and broke up the boxes. Aesthetics wasn't an issue as the wife had passed, but so long as they were reasonable looking like an old JBL 43xx series, she'd have been fine.

I have many, many excellent drivers on hand and haven't decided what to build as the CNC isn't set up yet, but it will be large.

 

[Jaxjax]

View attachment 444288

These aren't beauties, but they were some of the best speakers I've made.
18-inch bass, AMT tweeters, all Beyma components, external activation via the DCX2496 and PA multi-channel amplifier.
I think they could do everything you asked for here.

No, there beauties to be sure. My SO would also agree as speaker requirements here are black & preferably flat black. The fit & finish on those turned out excellent !! That is something I would like to hear . I have a never ending desire these days to feel my music when wanted & those appear to be able to do it in a fairly compact package.

 

[Jaxjax]

@Audionaut - they look good to me!

Again, speaking from experience, 8 cu feet is the size of a refrigerator. Are you settled with a home and don't plan to move? If you are settled and have a specific room they will live in - then design your speaker for the room!

Having really large enclosures with capable drivers is incredible but seriously consider the trade offs. I fly mine from the ceiling so they don't take up valuable floor space but this isn't ideal either. Optics fail, consider the size of these compared to the standard 32" doors.

View attachment 444289

I dig the make it happen !!!!

 

[Heinrich]

I dig the make it happen !!!!

Recently I realized a concept that wasn‘t aiming for feeling the sound, that impact you mentioned, but to hear down the deepest bass. More like looking at the sound, not so much the (in)famous immersion into it.

I see your point. Not addressing you in particular I still think that some numbers could help when deciding for an implementation. The 15“ bass, best taken from Altec or JBL is a legend originating in times long gone by. It could be, no hyperbole, that a modern 8“ outperforms what was deemed top of the line in 15“ back then. Don‘t judge by the looks.

Given the very same motor, a 15“ would give you just some insignificant 3dB more of max output relative to a12“, and an 18“ would add just and only another 3dB. The 18“ would need at least double the internal volume, and the ports would be like 20cm wide minimum plus a generous round over. The crossover would drop down to like 150 to 200Hz max. That sets high standards for the midrange, and you‘ll end up with a four-way. Anything from the hifi-shelf won‘t cope with the capabilities of the 18“ or that of a modern 15“ anyway.

Again, I don‘t want to distract you from the path taken, but it might be in order to comment on it.

 

[Audionaut]

I disagree, they're beauties!

they look good to me!

I agree with @JohnnyNG that they're lovely.

No, there beauties to be sure

I realize that I am part of an international forum here. Many thanks for the positive feedback.

My German friends and acquaintances thought the speakers looked: “a bit big”, “completely oversized - where should you put them in normal living rooms?” “God, they're ugly!” “Interesting (that's what they say in Germany when you don't want to offend anyone)”
My wife didn't say anything, but she's also really nice.

It's been a few years and I've since sold them below cost to someone who appreciates them.
We moved house and my wife no longer wanted the big black “things” in the living room.

I searched, but I couldn't find any more documentation, but I'll try to remember it:
The aim was to have linearly tuned speakers with consistent dispersion and the highest possible level reserves, with otherwise very good measurement values for the size and requirements.

Bass was a Beyma 18LEX1600Fe, midrange a 12-inch Beyma from the M series, which are also optimized for the midrange (some can also be used as bass-midrange drivers).
but I can't remember exactly which one it was because I have installed several types of them in projects. 12MCB700? 12MCS500?

The tweeter was a TPL 200 with a customized 3D printed horn, which a friend from a German forum printed for me in four parts. This resulted in a few hours of work on adjustments, sanding and painting and would have been unnecessary in retrospect, because the Beyma horn doesn't work any worse, it just has a slightly different outlet angle and I wanted to achieve an optimized dispersion pattern - and I also thought the look was better. (I was probably the only one)

I changed the crossover frequencies and EQ every few months during operation out of interest to see which filter types and settings I preferred. Sometimes preferences change.
Initial settings were (as far as I remember): 200Hz - 12db / 1.9kHz - 18db

No one has ever complained acoustically and I don't want to make any comparisons with ready-made speakers or other DIY projects, but I have rarely heard anything more convincing.
It is, among other things, the lack of any distortion even at very high volumes, which is always just a little more than idle for such speakers in the living room. Thanks to the large cone area, the listening impression remains consistent from very low to very high volumes, meaning that you can also hear very well at lower volumes. It wasn't easy for me to sell these little treasures.

To do my wife a favor, I then built loudspeakers whose target description was somewhat different: As small as possible, as loud as possible, yet as clean and linear as possible.

The result was this little power dwarf, which doesn't show its capabilities above 80 Hz.
From 90 Hz, I coupled another Beyma 18 inch as active support.

Acoustically similarly good, but visually much more discreet.

Thanks again for your kind feedback and I hope I was able to answer most of your questions.

 

[YSDR]

The ATC SCM 150 SL is a dream speaker for me or the 100 for that matter & would like to copy at least the aesthetics of them . I

As was mine, so I did a similar layout (but different drivers), 3-way active with punch, also can be converted to passive (now using like that) still have good punch.

 

[Audionaut]

The 15“ bass, best taken from Altec or JBL is a legend originating in times long gone by. It could be, no hyperbole, that a modern 8“ outperforms what was deemed top of the line in 15“ back then.

Which 8-inch speaker should be able to do what, for example, the already aged JBL 2226 is capable of?

 

[JohnnyNG]

View attachment 444381

I like the offset tweeters .

 

[YSDR]

And if it's ATC 'copying', personally I don't recommend the stepped front baffle of the consumer models, but the rounded edge baffle of the pro models.

 

[Heinrich]

... the already aged JBL 2226 ...

Aged I wouldn't say. I was talking about times when men still wore hats on a daily basis. When "the 15" was the real thing, and all below a sad compromise, when amps delivered 2 x 2Watts, if it was stereo at all. That's when the story of a capable 15" was born. Soon after it became a legend.

A deeper analysis of the before mentioned ATC would reveal difficulties, which are probably resolved with the actual product. And as said, I don't want to spoil your exitement with vintage design paradigms. But to call out it's vintage might be in order. That was the intention of my quoted post.