For some time I have been curious about the use of 15" "Pro" drivers in consumer speakers. I realize they have been a staple with horn-loaded 2-ways and 3-ways, but why aren't they more prevalent in other consumer designs What are the advantages of pairing it with conventional domes and cones? I ran across this speaker by ATC Loudspeakers. It is very similar to a design I've been toying with. I'd like to get everyone's input on the advantages and disadvantages of this kind of arrangement over a typical high-end 3-way using conventional 8", 10" and even 12" woofers.
EL150 | ATC Loudspeakers
EL150 | ATC Loudspeakers
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That ATC is just their Studio grade SCM150SL in a pretty frock. TBH I wonder why soffit mount never took off for home audio.
Pro woofer have high FS and need bigger boxes to not reach low at all.
not the same game at all.
I own both and have to use subwoofer with Pro stuff...
not the same game at all.
I own both and have to use subwoofer with Pro stuff...
My opinion is that all speakers require a subwoofer for best performance, so why hobble a 3-way with an anemic bottom octave and the inability to position the speaker for best low-end performance. This is why I'm exploring the benefits of a 15" mid-bass for my next 3-way design.
Funny you should bring that up. I've been contemplating a corner soffit-mount 2-way for a small room short on floor space, but that deserves its own thread.
To be honest... there is quite an overlap from Hi Fi intended woofers and Pro intended woofers. Usually the main 3 differences are durability, efficiency and max out put capabilities.
You can generally (with design concessions) make most Pro woofers work well in a Hi Fi application, but few Hi Fi woofers can survive in a Pro application. And there are a few that can excel at both.
Durability and high output capacities come at a price and are usually not required in most Hi Fi applications.
You can generally (with design concessions) make most Pro woofers work well in a Hi Fi application, but few Hi Fi woofers can survive in a Pro application. And there are a few that can excel at both.
Durability and high output capacities come at a price and are usually not required in most Hi Fi applications.
Mixing high efficiency woofers with domes is an issue
Normally, the tweeter has higher efficiency than the woofer(s) and is adjusted with L-pad resistors. Take a high efficiency woofer, say something that belts out 97dB 1w/1m and try to find a dome tweeter that efficient to "match". Granted, you can put an L-pad on the woofer but then just heating up the room and cooking power resistors.
For this reason, generally speaking most speakers that are very high in efficiency use compression drivers and horns.
You can use pro drivers with high efficiency dome tweeters--the smaller 8 and 6" pro drivers with horn loaded dome tweeters will get you there.
Here is an example of one of those designs
http://www.diysoundgroup.com/cobalt-mtm-kit.html
Normally, the tweeter has higher efficiency than the woofer(s) and is adjusted with L-pad resistors. Take a high efficiency woofer, say something that belts out 97dB 1w/1m and try to find a dome tweeter that efficient to "match". Granted, you can put an L-pad on the woofer but then just heating up the room and cooking power resistors.
For this reason, generally speaking most speakers that are very high in efficiency use compression drivers and horns.
You can use pro drivers with high efficiency dome tweeters--the smaller 8 and 6" pro drivers with horn loaded dome tweeters will get you there.
Here is an example of one of those designs
http://www.diysoundgroup.com/cobalt-mtm-kit.html
I would implement an active system. Still I was trying to find an efficient tweeter and midrange to minimize too much attenuation of any one signal. I was even thinking of using an M-T-M arrangement for better midrange efficiency.
A couple of things to keep in mind. If you have a pro woofer that is 95 db or so per watt, in most situations you will need to build in baffle step correction in the crossover... in the real world that is usually around 3 DB. I pick 95 db on the pro woofer because if you desire bass extension with reasonable out put potential, even with a 15", 93-96 dbw raw efficiency is where you going to end up. Example, FS in the 32-38 Hz area and Xmax of at least 4.5 mm peak.
My point is you are really dealing with a 92 db/watt or so woofer.
And if you are doing anything close to a 12 db/oct 2nd order slope 3 way, you are going to see a 2-2.5 db gain in the mid range band pass do to summation of the cross over (over lap). There are quite a few dome mid ranges that are available with true raw efficiencies of 89-92 db/w in their native operating range. On the baffle, 2nd order crossover in place you have 92-95 db/w effective (actual) mid range.
So a horn loaded mid range is usually not required.
As for the tweeter, there are several excellent horn loaded drivers available from all the major hi-fi driver manufacturers that really are 93-96 db/w efficient from 2.25Khz up.
In the end, a pro hi fi woofer can be a good thing, especially if you appreciate dynamics and the highest practical efficiency in an enclosure smaller than South Dakota.
My point is you are really dealing with a 92 db/watt or so woofer.
And if you are doing anything close to a 12 db/oct 2nd order slope 3 way, you are going to see a 2-2.5 db gain in the mid range band pass do to summation of the cross over (over lap). There are quite a few dome mid ranges that are available with true raw efficiencies of 89-92 db/w in their native operating range. On the baffle, 2nd order crossover in place you have 92-95 db/w effective (actual) mid range.
So a horn loaded mid range is usually not required.
As for the tweeter, there are several excellent horn loaded drivers available from all the major hi-fi driver manufacturers that really are 93-96 db/w efficient from 2.25Khz up.
In the end, a pro hi fi woofer can be a good thing, especially if you appreciate dynamics and the highest practical efficiency in an enclosure smaller than South Dakota.
Its intresting to see this because for the past mounth I have been contemplating a 15" 2-way with a CD down to 1000hz. I think the main advantage is sensativity, but you can also good decent bass although the enclosure is ganna be big. I plan on using a Eminence N314T-8 for the CD and a Eminence H14EA for the horn. It will be mated with a Beyma SM115/N which should get me to 40 hz or so in a 6 cubic foot enclosure. I want to style if from a vintage JBL.
Good point about BSC drawing down the effective efficiency of the mid-bass driver.
But maybe you can also agree that for most listeners a baffle step correction, which is usually designed-in (without any need to know how or why by the user), is usually an easier solution - isn't it ?
And we haven't even started with listeners that are living in a rented apartment or the ones who swap equipment very often .......
Regards
Charles
And we haven't even started with listeners that are living in a rented apartment or the ones who swap equipment very often .......
Regards
Charles
I don't think I'll ever understand the obsession with BSC indoors but there might be a point if the distance from speakers to room boundaries is measured in multiples of meters.
In my previous home the speakers were with their backs to the wall and I had to reduce low bass by about 5dB to get a flat in-room 20-20k response, in my current home they are in corners and I knocked off 8dB.
All this is running active with no BSC but with a BSC fixed in a passive xover the sound would be horrific.
In my previous home the speakers were with their backs to the wall and I had to reduce low bass by about 5dB to get a flat in-room 20-20k response, in my current home they are in corners and I knocked off 8dB.
All this is running active with no BSC but with a BSC fixed in a passive xover the sound would be horrific.
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