Dear all,
This is my first time posting to this forum, although I've been reading and using it as an important research resource for the past few years!
I've built a few speaker systems over the last 7 years or so, and after my last 'projects', I have a number of speakers that I would like to use together.
I have:
50 Aurasound NS3-194-16a 3" full range drivers
2 MCM 55-2421 8" woofers
(The Aurasounds were for the Murphy Corner Line Array design, if you're wondering why there were so many)
What I would ideally like to do is to create a stereo pair that sound really nice. I would be using them as studio monitors, and for me the qualities I'm looking for are musicality and imaging. Sensitivity is important, but I've found that with some designs that if it's the focus, it can lead to an experience that isn't as immersive as it could be.
The MCM woofers were intended for one of Bill Fitzmaurice's designs, but I ran out of money for the other components.
This may be the wrong forum to be in (I did spend 10-15 minutes deciding whether to post here, or the multi-way forum), but I was wondering what advice people had in terms of making use of any (or all) of these drivers.
I like the concept of corner-loading (especially with the Decware corner horn as an example), and horns, but I know my options are somewhat limited with what I have.
Thanks to everyone for your time, and I look forward to your suggestions, or advice on direction!
Dan
This is my first time posting to this forum, although I've been reading and using it as an important research resource for the past few years!
I've built a few speaker systems over the last 7 years or so, and after my last 'projects', I have a number of speakers that I would like to use together.
I have:
50 Aurasound NS3-194-16a 3" full range drivers
2 MCM 55-2421 8" woofers
(The Aurasounds were for the Murphy Corner Line Array design, if you're wondering why there were so many)
What I would ideally like to do is to create a stereo pair that sound really nice. I would be using them as studio monitors, and for me the qualities I'm looking for are musicality and imaging. Sensitivity is important, but I've found that with some designs that if it's the focus, it can lead to an experience that isn't as immersive as it could be.
The MCM woofers were intended for one of Bill Fitzmaurice's designs, but I ran out of money for the other components.
This may be the wrong forum to be in (I did spend 10-15 minutes deciding whether to post here, or the multi-way forum), but I was wondering what advice people had in terms of making use of any (or all) of these drivers.
I like the concept of corner-loading (especially with the Decware corner horn as an example), and horns, but I know my options are somewhat limited with what I have.
Thanks to everyone for your time, and I look forward to your suggestions, or advice on direction!
Dan
There are horn projects for the 55-2421 on the web. e.g.:
High output 8" Tapped horn
Building a tapped horn
High output 8" Tapped horn
Building a tapped horn
Thanks for the responses! It's certainly started me thinking 
I have plans for Bill Fitzmaurice's T18 sub, of which I can make two (seeing as I have 55-2421s) - it's good to see that it's a popular item and other options are out there.
As for the Aurasounds - it seems as if I could make use of the baffles I've created for the MCLA speakers, make minor modifications in order to use them as di-pole arrays. One thing I did notice with these in an array configuration was that it was somewhat difficult to get clean high-frequencies out of them. With EQing it can be done, but it sounded 'forced'. It's possible that for those speakers, they weren't placed close enough together in order to get those higher frequencies (wavelength between driver centres was too long).
So, I'd really like to pursue the option of single driver enclosures, with helper subs and possibly tweeters (if really needed). Would there be any use in looking for an enclosure that used these speakers in, say, a 2x2 configuration that could possibly replace a larger driver?
I have plans for Bill Fitzmaurice's T18 sub, of which I can make two (seeing as I have 55-2421s) - it's good to see that it's a popular item and other options are out there.
As for the Aurasounds - it seems as if I could make use of the baffles I've created for the MCLA speakers, make minor modifications in order to use them as di-pole arrays. One thing I did notice with these in an array configuration was that it was somewhat difficult to get clean high-frequencies out of them. With EQing it can be done, but it sounded 'forced'. It's possible that for those speakers, they weren't placed close enough together in order to get those higher frequencies (wavelength between driver centres was too long).
So, I'd really like to pursue the option of single driver enclosures, with helper subs and possibly tweeters (if really needed). Would there be any use in looking for an enclosure that used these speakers in, say, a 2x2 configuration that could possibly replace a larger driver?
With 50 Auras you have the option of matching a pair of them, and building a simple FAST with an 8", whilst leaving 48 for 2 array of 24 each....
Or.... You could do 5 arrays of 10 (awkward numbers for simple array impedance) and combine the 2 8" ers in the Centre channel, for a HT setup.
Or.... You could do 5 arrays of 10 (awkward numbers for simple array impedance) and combine the 2 8" ers in the Centre channel, for a HT setup.
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Hmmm .......
How to do something useful with 50 3" Drivers ?
Buy a shed load of Apex Jr $1 tweeters ?
Speaker Stuff
(They are surprisingly decent Audax from my research.)
Then blantantly ripoff the succinct details of :
http://www.parts-express.com/pedocs/manuals/301-980-audio-artistry-inc-cbt36k-manual-9148.pdf
Its doable but begs the question is it worth doing with very
cheap drivers ? I'd say it is if your up for it and have the
design skills to mug your way round all the problems,
and being able to implement it all on the cheap, with
passive line EQ and active x/o stuff around chip amps
biamping or possibly passive croosovers.
It could be done. But needs lots of skill.
rgds, sreten.
How to do something useful with 50 3" Drivers ?
Buy a shed load of Apex Jr $1 tweeters ?
Speaker Stuff
(They are surprisingly decent Audax from my research.)
Then blantantly ripoff the succinct details of :
http://www.parts-express.com/pedocs/manuals/301-980-audio-artistry-inc-cbt36k-manual-9148.pdf
Its doable but begs the question is it worth doing with very
cheap drivers ? I'd say it is if your up for it and have the
design skills to mug your way round all the problems,
and being able to implement it all on the cheap, with
passive line EQ and active x/o stuff around chip amps
biamping or possibly passive croosovers.
It could be done. But needs lots of skill.
rgds, sreten.
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Heh, although the 'ripoff' idea seems like a good one, I don't think I have the patience for such an ambitious project at the moment!
It seems like there is a lot of positive energy towards the dipole array design, and, to be honest, it's new to me. It's interesting how simple the construction side of things are for this, though, and that interests me in that I can certainly butcher what I have to make them!
Do I have to use 24 per side to have an effective array though? Could I do something smaller, maybe an array of 9, 12, or (dare I say it) even one in a different type of enclosure?
It sounds like the addition of a tweeter is going to be likely, but I'd like to keep my additional costs to a minimum for now - it certainly aids the WAF!
I was also thinking of using the MCM 55-2421s in an enclosure that the arrays (or whatever is decided on) can stand on, to create a stereo pair. HT and surround might be too much for me at the moment
For the subs, I could make Bill Fitzmaurice's T-18s, which sound quite nice and cross over at 80Hz, but I'm willing to explore other sub ideas (especially the high output tapped horn mentioned above), or a sealed or open cabinet.
It seems like there is a lot of positive energy towards the dipole array design, and, to be honest, it's new to me. It's interesting how simple the construction side of things are for this, though, and that interests me in that I can certainly butcher what I have to make them!
Do I have to use 24 per side to have an effective array though? Could I do something smaller, maybe an array of 9, 12, or (dare I say it) even one in a different type of enclosure?
It sounds like the addition of a tweeter is going to be likely, but I'd like to keep my additional costs to a minimum for now - it certainly aids the WAF!
I was also thinking of using the MCM 55-2421s in an enclosure that the arrays (or whatever is decided on) can stand on, to create a stereo pair. HT and surround might be too much for me at the moment
For the subs, I could make Bill Fitzmaurice's T-18s, which sound quite nice and cross over at 80Hz, but I'm willing to explore other sub ideas (especially the high output tapped horn mentioned above), or a sealed or open cabinet.
Tuba 18
CBT36 Line Array Speaker Kit Pair 301-980
The line array(s) are interesting; I'd would have to hear a $2,000 kit before jumping in. Not like you can re-purpose boxes of 3" drivers, which is commonly done with conventional size speaker drivers (and makes for a good hobby).
That mcm woofer; how long has that been around, 10 years? I bet they are thousands of them out there!
CBT36 Line Array Speaker Kit Pair 301-980
The line array(s) are interesting; I'd would have to hear a $2,000 kit before jumping in. Not like you can re-purpose boxes of 3" drivers, which is commonly done with conventional size speaker drivers (and makes for a good hobby).
That mcm woofer; how long has that been around, 10 years? I bet they are thousands of them out there!
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Very true. I think that means for my goals now that I should look for a way of replacing the Aurasound speakers with other drivers, so that I'm not trying to work around any limitations.
While there have been a lot of designs for arrays, I've seen a lot of designs for single drivers in differing configurations. In terms of cost, maintenance and sound quality I think that this is what I'd like to go for.
The back-loaded horn enclosures look quite cool, as well as being reported as an option that sounds good.
Maybe I could swap some (or all) of the Aurasounds with someone willing to part with two good single drivers? It might be Apples to Oranges, so I don't really expect that even though I'm hopeful
I've had the designs for the T-18 for a while, so I can save money by using that for the subs.
Well many here would really like to see the T-18 build and hear your impressions.
A swap is going to be hard work for the 3" - a pit fall of diy-ing speakers, some are going to end up on shelves; have several of the 55-2421, which is fine, I'll use them someday.
Did you see this thread? It started about the same time as yours- check it out:
http://www.diyaudio.com/forums/multi-way/245304-first-build-recommendations.html
A swap is going to be hard work for the 3" - a pit fall of diy-ing speakers, some are going to end up on shelves; have several of the 55-2421, which is fine, I'll use them someday.
Did you see this thread? It started about the same time as yours- check it out:
http://www.diyaudio.com/forums/multi-way/245304-first-build-recommendations.html
Heh, although the 'ripoff' idea seems like a good one, I don't think I
have the patience for such an ambitious project at the moment!
Hi,
Fair enough, but don't expect other simpler approaches to work well.
Simple fact is using lots of 3" drivers is always going to be ambitious.
Clueless simplicity does not make it simpler, its just more wrong.
rgds, sreten.
HTML:
http://billfitzmaurice.info/forum/viewtopic.php?f=13&t=7673It seems that the older threads I'd created on those forums have disappeared, but I did build a pair of Bill's SLAs, an AutoTuba, and an Omni15 Bass cab.
Since then I've moved from England to America, and so I'm effectively starting again. I was going to build a pair of his David stereo floor-standing speakers (a folded horn combined with an MTM), but again ran out of money for the expensive parts. Still, I finished one to the point where I could use it as a sub with one of the 55-2421s, and it's amazing! I've combined it with a couple of different speakers, and it fits seemlessly into the room...to the point where you wonder if it's actually running, but when you disconnect it the bottom falls out of your world
The SLAs were also very sensitive and detailed, but a little 'cold' sounding to me. I think my ear tends to lean towards a smaller number of drivers, as I've found the same in my Bass playing career. I tend to go for the big 15" cabinets over a 4x10", because I (and the bands I've been in) find I fit better into the overall sound.
Rambling aside, I've been reading up on the Spawn series of Frugal Horn speakers, mentioned on these forums, and in other realms of the internet. I really like the design, and could see them being a good fit for my purpose. Strangely (or not), my wife likes how they look too, so that's a definite bonus!
Here's a quick picture I'd taken when I'd finished the Murphy Corner Line Arrays, containing the Aurasounds (they were sensitive, but I could never get the EQ to make them sound really good, most likely because the cabinets were designed for the ND90):
I might put the Aurasounds on eBay or something, as I don't think I'll make use of them again. They did well for their experiment, but I need to be more serious about my decisions for now, and a stereo system comprising of only four drivers is very tempting.
I'll do some more reading on this design, but if there are any comparative designs that are worthy of note, please let me know!
Thanks,
Dan
Hi,
FWIW its worth you can repurpose drivers if you know what you are doing.
e.g. take a cheap decent small tweeter :
Vifa BC25SC55-04 1" Square Frame Tweeter 264-1024
Add 4 NS3 drivers as a MMTMM with a slight tweak to roll off the outer pair
at ~ 1KHz*, the inner pair working up the the x/o point. Then add a further
4 NS3's to turn it into a 2.5 way and a MMMMTMMMM. A good plan for
the cabinet would be a sliced open PVC pipe forced open by the baffle.
Two ridges in the baffle sides to locate the pipe edges.
Mass load the bottom of the pipe with sand.
See here for a useful discussion of a tall MMTMM :
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
[Here we have just changed it to (MM)(MM)(T)(MM)(MM).]
It won't go low but biamping with stereo subs will work. I know that
MCM driver well, and its very good in small cabinets, with an ABR/PR,
you best bet nowadays is the PE 10" PR to go with it in a small cab.
Line level 1st order high pass will tame any upper bass excess to
gives a decent roll off that can mate to stereo subs run quite high.
rgds, sreten.
* Looks like you can do this, exploiting the drivers peak in the mid.
FWIW its worth you can repurpose drivers if you know what you are doing.
e.g. take a cheap decent small tweeter :
Vifa BC25SC55-04 1" Square Frame Tweeter 264-1024
Add 4 NS3 drivers as a MMTMM with a slight tweak to roll off the outer pair
at ~ 1KHz*, the inner pair working up the the x/o point. Then add a further
4 NS3's to turn it into a 2.5 way and a MMMMTMMMM. A good plan for
the cabinet would be a sliced open PVC pipe forced open by the baffle.
Two ridges in the baffle sides to locate the pipe edges.
Mass load the bottom of the pipe with sand.
See here for a useful discussion of a tall MMTMM :
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
[Here we have just changed it to (MM)(MM)(T)(MM)(MM).]
It won't go low but biamping with stereo subs will work. I know that
MCM driver well, and its very good in small cabinets, with an ABR/PR,
you best bet nowadays is the PE 10" PR to go with it in a small cab.
Line level 1st order high pass will tame any upper bass excess to
gives a decent roll off that can mate to stereo subs run quite high.
rgds, sreten.
* Looks like you can do this, exploiting the drivers peak in the mid.
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Thanks for the response sreten! I think this is an idea that can steer me in a good direction
Construction-wise, it sounds quite simple - it'll just be the calculations to get there that'll be a possible challenge.
I wanted to make sure that I was visualising your idea correctly. Something like this?
It also sounds like the top of the tube will be open-ended, but I may have misunderstood, and the design is like the ZA5 where it is closed, but with rear ports.
I like the idea, so thanks for taking the time for the hypothesis!
I'll have to dig through the forums on the T18s, and see what their advisable HF roll-off actually is. As you've eluded to, it may require a different enclosure for the subs.
Thanks,
Dan
Construction-wise, it sounds quite simple - it'll just be the calculations to get there that'll be a possible challenge.
I wanted to make sure that I was visualising your idea correctly. Something like this?
It also sounds like the top of the tube will be open-ended, but I may have misunderstood, and the design is like the ZA5 where it is closed, but with rear ports.
I like the idea, so thanks for taking the time for the hypothesis!
I'll have to dig through the forums on the T18s, and see what their advisable HF roll-off actually is. As you've eluded to, it may require a different enclosure for the subs.
Thanks,
Dan
You can use the mcm woofers in a very small box, .3 - .35 with a PR. Which requires careful planing for the both drivers and/or plate amp (crowded). As I remember the mcm woofer is good to about 200hz, but peaks up after that.
A small box would look good under the mini Line Array, but expensive, the PE PR cost as much as the woofer
A small box would look good under the mini Line Array, but expensive, the PE PR cost as much as the woofer
Attachments
Hi,
That is the basic idea, but to get the tweeter to typical ear level it
would need to be quite a bit taller. I'd build it sealed and well stuffed.
Wiring the pairs in series will give an overall 8 ohm speaker.
With the suggested 4 ohm tweeter the L-pad will bring it up.
For the MTM inner pairs capacitors across the outer two will
roll off the upper midrange and boost the upper midrange
of the other driver. It all needs careful modelling IMO.
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
Unfortunately MCM no longer sell the budget 10"
PR that went well with the MCM 8" driver.
http://www.diyaudio.com/forums/subwoofers/80138-sillys-1st-sub-8-mcm-55-2421-a.html
rgds, sreten.
That is the basic idea, but to get the tweeter to typical ear level it
would need to be quite a bit taller. I'd build it sealed and well stuffed.
Wiring the pairs in series will give an overall 8 ohm speaker.
With the suggested 4 ohm tweeter the L-pad will bring it up.
For the MTM inner pairs capacitors across the outer two will
roll off the upper midrange and boost the upper midrange
of the other driver. It all needs careful modelling IMO.
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
Unfortunately MCM no longer sell the budget 10"
PR that went well with the MCM 8" driver.
http://www.diyaudio.com/forums/subwoofers/80138-sillys-1st-sub-8-mcm-55-2421-a.html
rgds, sreten.
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Interesting. That works for me!
The only passive radiator sub (PR) that I've experienced myself was part of a 2.1 system by Logitech a number of years ago. The sub itself was pretty impressive in a small room. The PR was the only moving part to reach the outside world, as the actual driver was smaller, and used a transmission line from the back of the driver to combine with the front to 'actuate' the PR.
I've noticed that the consensus is to not use a horn sub, and employ a small enclosure. The T-18 subs are basically a 14" cube, so they aren't offensive in size, and may make a good sized stand for the MM MM T MM MM 'tops'.
A quick guess at my current ear level would be ~45", so the height of the tweeters would need to be something like 31" from the top of the T-18. With that in mind, it sounds like the MM MM T MM MM enclosures would need to be 62" high for symmetry purposes.
Do my maths work out so far?
Here's a SPL chart for the T-18:
Thanks again everyone for the discussion, and particularly you looking into the details sreten!
Dan
The only passive radiator sub (PR) that I've experienced myself was part of a 2.1 system by Logitech a number of years ago. The sub itself was pretty impressive in a small room. The PR was the only moving part to reach the outside world, as the actual driver was smaller, and used a transmission line from the back of the driver to combine with the front to 'actuate' the PR.
I've noticed that the consensus is to not use a horn sub, and employ a small enclosure. The T-18 subs are basically a 14" cube, so they aren't offensive in size, and may make a good sized stand for the MM MM T MM MM 'tops'.
A quick guess at my current ear level would be ~45", so the height of the tweeters would need to be something like 31" from the top of the T-18. With that in mind, it sounds like the MM MM T MM MM enclosures would need to be 62" high for symmetry purposes.
Do my maths work out so far?
Here's a SPL chart for the T-18:
Thanks again everyone for the discussion, and particularly you looking into the details sreten!
Dan
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