Feeling it's time for a project and have been keen on building a line array for some time. Have read lots here and a few papers over the years.
What do people think of the following driver:
https://www.daytonaudio.com/product...-magnet-aluminum-cone-full-range-driver-8-ohm
Considering using 32 of them per stack, without the addition of tweeters. Would such an abundance of smallish drivers with seemingly OK high-end negate the requirement for addressing the high frequency?
For info, I can't hear a thing above 14 kHz, am 41 and plan on getting older where I'm expecting to largely appreciate wonderfully clear mids.
I do have some experience with miniDSP products, making measurements and tinkering with EQ.
If these drivers are not considered good, then curious to find another ~2.5" ish that would do the job. However, I like the idea of giving them a try but couldn't resist asking the community how daft my idea is first.
Lastly, don't let anyone in the Elsinore thread know I'm planning to build something to compete with them for movie night. My Elsinore's are great, but I want a new toy.
What do people think of the following driver:
https://www.daytonaudio.com/product...-magnet-aluminum-cone-full-range-driver-8-ohm
Considering using 32 of them per stack, without the addition of tweeters. Would such an abundance of smallish drivers with seemingly OK high-end negate the requirement for addressing the high frequency?
For info, I can't hear a thing above 14 kHz, am 41 and plan on getting older where I'm expecting to largely appreciate wonderfully clear mids.
I do have some experience with miniDSP products, making measurements and tinkering with EQ.
If these drivers are not considered good, then curious to find another ~2.5" ish that would do the job. However, I like the idea of giving them a try but couldn't resist asking the community how daft my idea is first.
Lastly, don't let anyone in the Elsinore thread know I'm planning to build something to compete with them for movie night. My Elsinore's are great, but I want a new toy.
If you're set on 2 1/2 drivers, disregard this post. If you're open to 4 inch drivers, here's a pretty novel idea.
https://www.madisound.com/pdf/TheCHRArray-plan-250811.pdf
https://www.madisound.com/pdf/TheCHRArray-plan-250811.pdf
That's a neat modular system. But specifically interested in opinions about using these 2.5" drivers.
I'm liking the square front plate which should make mounting them neat as well as the datasheet's performance curve. Obviously, I'd buy a sample before diving in.
I'm liking the square front plate which should make mounting them neat as well as the datasheet's performance curve. Obviously, I'd buy a sample before diving in.
OK, somethings to consider is that the lower the frequency, the wider its BW and that the majority of acoustic power is in the < ~500 Hz BW, so a good argument can be made based on these music, hearing charts to concentrate on getting this up to ~12.5 kHz as good as the budget allows and tack on/EQ the extremes for LFE, top end 'sizzle'/'air'.
But if we accept the pioneer's (Bell Labs/W.E.) 80 - 12.5 kHz BW sufficient for full range vocals, then the mean acoustic power = 1 kHz = ~ 4.311"/10.95 cm effective dia. and if the baffle/room boundaries 'support' the < 500 Hz BW, then the mean is 2.5 kHz, shrinking the driver to ~ 1.72"/4.38 cm with your proposed driver ~ 2.126"/5.4 cm = ~2027 Hz mean 'favoring' a larger driver.
Historically, the pioneer's initially concentrated on getting the 250-2.5 kHz analog and later the 300 - 3.0 kHz digital telephone BWs 'flat' @ 'x' SPL, though eventually changing it over time to adapt it to ever increasingly wider BW/apps, so ultimately we're needing a 3 way line array with the McIntosh XR-290 demo for the most part forever 'spoiling' me on accepting any less for a truly wide range system at minimum regardless of speaker alignment type.
In short, we're caught between a 'rock and a hard place' in that we ideally need a fairly large driver or at least a 2 way + sub system, so all things considered it seems you chose well enough overall spec-wise for your intended (limited HF) app if with a wide enough baffle to support ~80 Hz/F6 in room or willing to trade efficiency for BW and EQ flat.
But if we accept the pioneer's (Bell Labs/W.E.) 80 - 12.5 kHz BW sufficient for full range vocals, then the mean acoustic power = 1 kHz = ~ 4.311"/10.95 cm effective dia. and if the baffle/room boundaries 'support' the < 500 Hz BW, then the mean is 2.5 kHz, shrinking the driver to ~ 1.72"/4.38 cm with your proposed driver ~ 2.126"/5.4 cm = ~2027 Hz mean 'favoring' a larger driver.
Historically, the pioneer's initially concentrated on getting the 250-2.5 kHz analog and later the 300 - 3.0 kHz digital telephone BWs 'flat' @ 'x' SPL, though eventually changing it over time to adapt it to ever increasingly wider BW/apps, so ultimately we're needing a 3 way line array with the McIntosh XR-290 demo for the most part forever 'spoiling' me on accepting any less for a truly wide range system at minimum regardless of speaker alignment type.
In short, we're caught between a 'rock and a hard place' in that we ideally need a fairly large driver or at least a 2 way + sub system, so all things considered it seems you chose well enough overall spec-wise for your intended (limited HF) app if with a wide enough baffle to support ~80 Hz/F6 in room or willing to trade efficiency for BW and EQ flat.
My Modified CBT24 design uses a SB Acoustics 2.5" diameter cone driver. Each array uses 24 of these drivers and they are augmented by dual 12" subwoofers for coverage of the lowest frequencies. The CBT design (based on original work by Don Keele) uses a curved cabinet. I have a thread on this design at:
https://www.diyaudio.com/community/threads/my-new-line-array-its-a-modified-cbt24.313352/
You may enjoy reading about this design and how it progressed. These arrays are my daily listening speakers in my living room.
Of course my near field line array white paper is a starter read for linear line arrays and can be found at:
http://www.audioroundtable.com/misc/nflawp.pdf
Jim
https://www.diyaudio.com/community/threads/my-new-line-array-its-a-modified-cbt24.313352/
You may enjoy reading about this design and how it progressed. These arrays are my daily listening speakers in my living room.
Of course my near field line array white paper is a starter read for linear line arrays and can be found at:
http://www.audioroundtable.com/misc/nflawp.pdf
Jim
Hi Jim,
Have read your posts there before - part of the reason for feeling enthusiastic about this.
Good idea about the CBT notion. I'll wire them such that a crossover/delay can be used to achieve similar from a straight system. Or at least not corner myself such that it can't be modded for later...
With 32 of the DMA70-8 drivers, the array should be 2.24 m tall. There's scope for about 50mm extra top and bottom for the cabinet/legs before I'm running out of ceiling space. An interesting idea is to have floor-to-ceiling (or close enough) to mimic an infinite array with reflections. 2.4 m ceiling here...
Your arrays look awesome!
Have read your posts there before - part of the reason for feeling enthusiastic about this.
Good idea about the CBT notion. I'll wire them such that a crossover/delay can be used to achieve similar from a straight system. Or at least not corner myself such that it can't be modded for later...
With 32 of the DMA70-8 drivers, the array should be 2.24 m tall. There's scope for about 50mm extra top and bottom for the cabinet/legs before I'm running out of ceiling space. An interesting idea is to have floor-to-ceiling (or close enough) to mimic an infinite array with reflections. 2.4 m ceiling here...
Your arrays look awesome!
Get a sample driver, if you like it, then move on to the next step. In an array, the character of the driver prevails, you get it back on steroids.
If the FR sheets are honest it seems to be a fun driver to use. Decent x-max, it could use bottom end support with a couple of subs.
I'd prefer a driver with a rising response towards the high frequencies, but there isn't that much available or affordable in this size driver.
There are lots of options when building an array. One could go the CBT route, as outlined by Jim, or go for a straight floor to ceiling array, the closest example to your driver size would be the one from nc535: https://www.diyaudio.com/community/...ne-array-for-wall-or-corner-placement.337956/. He used a corner array, but a freestanding array might have some more freedom to adapt to the room. Arrays do quite well to work with a room, straight arrays basically (seem to) avoid floor and ceiling and all objects smaller than itself. But it does still reflect off of parallel planes. So you might think about helping it with a bit of treatment. A bend CBT can function quite well in an untreated space.
In the thread I linked, there are a couple of other options researched. One of those is a shaded version of the straight array. @nc535 made a simulation model in Vituixcad to play with, the thread is full of simulations of all kinds of array processing: https://www.diyaudio.com/community/...-corner-placement.337956/page-21#post-6165665
Even though I've had arrays myself for years, I have learned a lot from those simulations and it even made me switch from a straight unshaded array towards a frequency shaded array.
If the FR sheets are honest it seems to be a fun driver to use. Decent x-max, it could use bottom end support with a couple of subs.
I'd prefer a driver with a rising response towards the high frequencies, but there isn't that much available or affordable in this size driver.
There are lots of options when building an array. One could go the CBT route, as outlined by Jim, or go for a straight floor to ceiling array, the closest example to your driver size would be the one from nc535: https://www.diyaudio.com/community/...ne-array-for-wall-or-corner-placement.337956/. He used a corner array, but a freestanding array might have some more freedom to adapt to the room. Arrays do quite well to work with a room, straight arrays basically (seem to) avoid floor and ceiling and all objects smaller than itself. But it does still reflect off of parallel planes. So you might think about helping it with a bit of treatment. A bend CBT can function quite well in an untreated space.
In the thread I linked, there are a couple of other options researched. One of those is a shaded version of the straight array. @nc535 made a simulation model in Vituixcad to play with, the thread is full of simulations of all kinds of array processing: https://www.diyaudio.com/community/...-corner-placement.337956/page-21#post-6165665
Even though I've had arrays myself for years, I have learned a lot from those simulations and it even made me switch from a straight unshaded array towards a frequency shaded array.
I second the notion that the array should be free standing. I actually used mine out in the room - which was a garage - and aimed them at the LP. I found that I couldn't get them tight enough into the corners to totally avoid boundary nulls. They need to be pulled out far enough so you can treat the nearby walls for reflections. Pulling them out from the wall leaves room for subs behind them.
I too like the Dayton DMA series drivers. My favorite for line arrays is the 1.5" DMA 45 which has a rising response above 15 khz. Its also slightly smoother throughout and has better dispersion so I would prefer it to the DMA 70, despite needing 50% more of them. The onset of combing will be 70/45 higher in frequency. Combing really isn't audible at >3m or so listening distance but I have to believe the vertical sidelobes in the combing region are detrimental to some extent.
I too like the Dayton DMA series drivers. My favorite for line arrays is the 1.5" DMA 45 which has a rising response above 15 khz. Its also slightly smoother throughout and has better dispersion so I would prefer it to the DMA 70, despite needing 50% more of them. The onset of combing will be 70/45 higher in frequency. Combing really isn't audible at >3m or so listening distance but I have to believe the vertical sidelobes in the combing region are detrimental to some extent.