New Thread: ER Audio Mini Panels
Come on, guys, we need to have our own thread on these panels!
They're not expensive, they have their own bias supply, crossover
and ER Audio claims they do down to 200Hz.
Aren't you curious to know what they'd sound like crossed with your favorite midwoofers and subs below that?
ER Audio says that you can also order the panels alone to connect them in arrays for greater dispersion, and save on power supplies in the process.
Mini Panels
ER Audio mini panels
Come on, guys, we need to have our own thread on these panels!
They're not expensive, they have their own bias supply, crossover
and ER Audio claims they do down to 200Hz.
Aren't you curious to know what they'd sound like crossed with your favorite midwoofers and subs below that?
ER Audio says that you can also order the panels alone to connect them in arrays for greater dispersion, and save on power supplies in the process.
Mini Panels
ER Audio mini panels
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Definitely.
I'm really tempted to order 2 or 4 of them to replace my Acoustat front panels, unfortunately the price went up by 25% recently (but they're still not that expensive). I would of course like to XO them as low as possible, definitely below 300 Hz. Rob at ER Audio wrote that they are working on measurements that will be published on the web site soon.
So, any opinions/info about the mini panels would be appreciated
I'm really tempted to order 2 or 4 of them to replace my Acoustat front panels, unfortunately the price went up by 25% recently (but they're still not that expensive). I would of course like to XO them as low as possible, definitely below 300 Hz. Rob at ER Audio wrote that they are working on measurements that will be published on the web site soon.
So, any opinions/info about the mini panels would be appreciated
The very First ESL's that I built were that size back in 2003.
They will produce 200hz with a large enough D/S but not anything earthshaking on a small power amplifier.
IMHO, Way way over priced for a panel that size and cost no more than about $20 a pair to DIY.
I can get 95db to 100db FLAT down to 50Hz to 100hz using my 9.75" x 3.25" and a sealed 5 1/4" woofer on about a pair of 50-80 watt amps setup in a bi-amped configuration.
I have shown the FR chart and pictures many many times already in many recent threads.
Just one of these panels with my 8" sub is enough to fill a 11'x 18' room your causing you to yell in order to carry on a conversation and enough lows to make it sound full and punchy without breaking a sweat!
It is not hard to build something like that.
I have been contemplating recently on starting a new build thread this summer on how to produce the set that I made back in 2003 since I burned up my best pair two years ago, in the name of science and seeing how far I could take them even with the few flaws they did have.
They worked perfectly for 9 years until I decided to push them past there limits!! He,he,he,he
I have already made a TIG rod segmented design that i have yet to put a diaphragm on and test it.
This design was fully documented at ESLDIY but they lost all of the very detailed pictures I had there.
Anyhow, I want to make a new one using the original window screen method I had used when I started making these things so I can still use my original diaphragm frames, I just need to make some new stator panels.
Also in the works is a PCB model made out of some stator's that DIY'er WrineX was kind enough to send me that are the exact same size and then compare them all to each other.
I know I have been behind the times of getting anything done as it is just a hobby for me and I have been focused lately on learning C and programming PIC chip MCU's.
It is not good to have HV flying around when my bench is loaded with IC's.
A parallel chipamp is in the works to in order to handle to low impedance's, and, a 4Kv P-P direct drive amp is in the plans for the small desktop systems as well, I just got the FET's for that last year.
So my plate is full but with lots of stuff to do, but as usual I am always happy to provide my knowledge and experience with such systems when I can for those who are already on it!!
Cheers!!!
jer
They will produce 200hz with a large enough D/S but not anything earthshaking on a small power amplifier.
IMHO, Way way over priced for a panel that size and cost no more than about $20 a pair to DIY.
I can get 95db to 100db FLAT down to 50Hz to 100hz using my 9.75" x 3.25" and a sealed 5 1/4" woofer on about a pair of 50-80 watt amps setup in a bi-amped configuration.
I have shown the FR chart and pictures many many times already in many recent threads.
Just one of these panels with my 8" sub is enough to fill a 11'x 18' room your causing you to yell in order to carry on a conversation and enough lows to make it sound full and punchy without breaking a sweat!
It is not hard to build something like that.
I have been contemplating recently on starting a new build thread this summer on how to produce the set that I made back in 2003 since I burned up my best pair two years ago, in the name of science and seeing how far I could take them even with the few flaws they did have.
They worked perfectly for 9 years until I decided to push them past there limits!! He,he,he,he
I have already made a TIG rod segmented design that i have yet to put a diaphragm on and test it.
This design was fully documented at ESLDIY but they lost all of the very detailed pictures I had there.
Anyhow, I want to make a new one using the original window screen method I had used when I started making these things so I can still use my original diaphragm frames, I just need to make some new stator panels.
Also in the works is a PCB model made out of some stator's that DIY'er WrineX was kind enough to send me that are the exact same size and then compare them all to each other.
I know I have been behind the times of getting anything done as it is just a hobby for me and I have been focused lately on learning C and programming PIC chip MCU's.
It is not good to have HV flying around when my bench is loaded with IC's.
A parallel chipamp is in the works to in order to handle to low impedance's, and, a 4Kv P-P direct drive amp is in the plans for the small desktop systems as well, I just got the FET's for that last year.
So my plate is full but with lots of stuff to do, but as usual I am always happy to provide my knowledge and experience with such systems when I can for those who are already on it!!
Cheers!!!
jer
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I don't doubt it, yet everyone raves about Rob's full range Acorns, so I wouldn't think he's the deceptive sort.
In any case, would you cross them with this driver
http://www.greatplainsaudio.com/downloads/416-8B Spec Sheet.pdf
Gary Dahl, crosses them with his Azurahorn/Radian driver, where the 416s begin at 700Hz. His 3 cu ft sealed boxes cut off their low end at 70Hx, below which his subs take over. Bi-amping too?
That's fine, since my room is small, and I may be bi-amping anyway.
$20? Including the transformers and the rest of circuitry?
WADR, it may hard or too entailed for many of us to build. Indeed, the biggest problem DIYing with ESLs is that there's practically zero pre-made HF or HF/MF ESL drivers available off the shelf for purchase anywhere in the world; good performing ones, anyway.
It's very upsetting that there's no one in the USA who makes anything but ultra expensive full range stats. That's the problem as I see it. So if noobs like me want to buy off the shelf HF/MF ES drivers, the ER Audio Mini Panels is the only game in town. And again, they're made by the same guy who makes the very well respected Acorns-probably the most affordable full range ESLs anywhere.
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According to which formula? Using the equation from the SPL of ESL thread you can get about 93 dB @ 1 m @ 200 Hz using one mini panel, and about 99 dB using two stacked panels. Using Linkwitz dipole SPL calculator I get about the same SPL with a Xmax of 0.5 mm (don't know how accurate that is with an air gap of 1 mm). For a small room I think that's enough.
In what way are they inconsistent? The panel has three vertical segments where the center segment is 30 mm wide, and the outer segments about 43 mm wide (the conductive part). The active height is 487 mm.
It's hard for someone who don't have the tools and experience.
The diaphragm stretching, stator coating etc. seems complicated for me.
And I would prefer a segmented design which would make the perforated panels even harder to build. Maybe wire stators would be feasable, but still a lot of work (and they don't look as good).If you're gonna use subs I would definitely go with OB woofers between 80-300 Hz. I use U-baffle woofer towers with four 7" drivers per tower. They mate very well with the ESL panels, are usable down to about 40 Hz and look great.
To use OB woofers without subs you need to move a lot of air to get low freq. Something like Dayton Audio UM15-22 in a U- or H-baffle might work decently below 30 Hz. But then you also need an amp with a lot of power (class D preferably).
I quite don't understand. Even if the mini panels can go down to 200Hz, why not make it "easier" on them and cross them with something like the Altec 416 midwoofers at around 500Hz (the Altec 416s can actually do up to 1kHz without becoming directional)?
Is the RC crossover that comes with the mini panels what you would use between them and the Altecs?
Another thing: The 416s have 98db sensitivity. If I don't bi-amp the system, how would I match the levels between the the panels and the 416s?
Gary Dahl's sealed boxes limit the 416's low end to 70Hz.
So what do you think of a pair of Brian Ding's Rythmik sealed servo subs
Rythmik Audio • Servo subwoofer products ?
Acorns: Too big for my room?
I
This is probably a silly question, but, assuming I could find someone to build them for me from the kits, would the Acorns be too big for a 12 ft x 13 ft room? I would bi-amp them. Acorn Electrostatic Loudspeaker Kit
I
Well, I want the superior ESL sound as low as possible in freq, while still having reasonable max SPL, low distortion and good linearity.
I would definitely recommend DSP, active XO and bi/tri-amping.
The Altec driver has high sensitivity but 4 mm xmax is puny compared to more modern 15" (or smaller) drivers. I really don't see why you would use that driver instead of a smaller driver with higher xmax (unless you have a really weak amp).
Don't have any experience with those, the technology looks interesting though.
I have found that Bi-amping is really the only way to go, I tried to design some passive crossovers but have to have a working system in order to properly tweak it.
I tried to design one for my system using spice but the more I got it to where I wanted it to be required some components that didn't justify the cost and I didn't like what it was dong to the phase response.
My First crossover was just a series capacitor and it worked okay as well with the ESL coming in above 400hz or so.
As far as cost goes, The size of the panel, Construction Technique and amount of material for the size will justify this.
Perforated metal cost's where to high for me when I started so I looked for cheaper materials and I found that plain ole' window screen was my best bet for medium to small panels and it worked great!!
Then I moved on to a more expensive method of using TIG rod although it was still much much cheaper than perforated metal.
I have been wanting to build a small set using some Lincane that you can find at Home Depot but the cost of it has gone way up through the years though it is still feasible for a small panel.
It is a bit thin to be used in a big panel but it is possible providing you have ample support for stability as it bends very easily.
When I got the bug I looked for anything and everything I could possibly use to build a set.
Being unemployed at the time, I spent about $200 on different materials and found my window screen method was the cheapest I could come up with at the time and it still stands.
I did switch to the TIG rod method later on, building some 36"x 10.5" stator's and then perfected their use with my latest little panel.
CharlieM's newest design for his big system is an extension of such a design using TIG rod and is a real testament to using the material.
And of course also mention that it is a segmented design as well!!
The electronics is pretty much a solid investment no mater the size of you panels due to the cost of the transformer's.
Reducing this cost is something that I have been working on and is my main focus.
Panel efficiency and a High Bias voltage has a lot to do with this.
It has been shown in the past that you could get away with under $100 for the interface setup, to as much as $200 or more if you want run high power going as low as 150Hz to 180Hz.
If you can find some Acoustat Interfaces cheap..Get Them !!!!
I have tested to Antek 1206 (using the 6V winding as a primary) with my Crown DC300a full power (40Vrms) and performed fine to the point of core satuartion of 360hz to 300Hz, this is a $22 transformer an you will need 4 of these for a stereo setup.
The Antex AS-1206 produced 4500Vpeak of output for just one transformer at that level (40Vrms).
My only recommendation is to stay away form the shielded types (AS-xxxx).
The shielded type is more prone to arc and short the winding's, at least this happened in my test and it also adds more to the overall stray capacitance that the transformer has.
Luckily I was able to repair it and left the shield off ( now a AN-1206) and it never failed again after that.
The part that has been tried and true by DIYer's is the 50watt model but they only make the shielded versions now.
If you wanted to go through the trouble then you can either use the shielded type and not push them or go through the painstaking process of removing the shield.
They do make a 25 watt model (AN-0206) and it is only $11 and I would think that it should be fine for small to medium powered setup, I have not tested one of these yet.
I am working on a recipe for a DIYer friendly DIY ESL transformer but I don't have the funds for the materials yet.
More on this later.
I wind my own primary on a selected core to get a higher transformation ratio for my smaller panels and of course I use a higher crossover frequency to suit as well.
This won't be necessary for a large panel in the 3 to 4 square foot range or larger.
It will produce plenty of sound even for a small amp in the 40 watt to 100 watt range.
It is mostly about the voltage swing (and Bias).
With the common 1:80 ratio that two of these cores offer, it gives you 9Kv p-p across the stator's with a big amp like my Crown DC300a.
That is still a lot of sound for your average panel size!!!
Providing that your are using a high bias voltage and a stator coating that won't give out on you, you would rarely need more that about 20Vrms and less for normal listening at 90db or so.
I am in no way knocking ER's products and I do owe them a lot for their inspiration of getting me to finally devulge in to this hobby all the way back to (before) 2000 or so.
As far as tools are concerned all I needed are common house tools that you would use to build a model airplane kit nothing special including a heat gun the shrink the diaphragm, the rest was all labor and patients.
If you wish to build mechanical stretcher go for it, I haven't needed one yet for my panels up to 7.5" wide, someday I will get around to making one if I start making large panels someday but I doubt personally that I will ever need one.
All of the experimenting for most part have already been done in these threads and there are only a few simple rules to follow and the main one "That I Cannot Stress Enough" is, Make sure your stator coating has sufficient thickness for the voltage range that you are planning to run your ESL's at and you won't have any issues at all when you fire them up for the First time!!
The second one of course is the Diaphragm coating and I only have one name for that "Licron" or "Licron Crystal" has been proven to work the first time and for many many many years.
I know there are other alternatives out there and it is not cheap but it works and works reliably as far as know and my own experience.
My advice has always been to get the transformers and bias supply made and then start building small panels for a start using the techniques found in these threads.
Many have done this and many I have yet to hear from again because they are to busy enjoying what they have created and like I have done.
It easy enough to do, and they are probably building different sizes to try for themselves and their friends, Who Knows!!!!
I actually know of a few that are doing this.
I know of one DIYer that you may be able to contact is "Dochungwell" he has been building his model for people and is trying to produce a kit form package as well, and maybe he can set you up, especially with a pre-made Interface unit.
If you can't get a hold of him let me know I can/will contact him for you as we have collaborated a lot in the last few years, he is located in Florida.
Anyhow as I had mentioned before, the most extreme test I had done on my little panel is when I was running about 6.5kv of bias ans had approximately 22-25KV across the stator's I had about .090 to .110 of D/S and my little panel was producing a 200Hz sine wave quite nicely and it was loud enough to scare me out of the room, above that to 1000hz and above it was unbearable and I like it loud typically 110db for me is not an issue.
I ran it like that for about 20 minutes straight until the stator coating gave out.
Again, I cannot stress stator coating enough!!!
I tried and tried to repair that panel but I never got it to that level again, and, sadly I didn't have an SPL meter at the time I did that test.
But even after the repairs I was still able to get well over +105db reliably with up to a 8Kv bias and and only 20Vpeak into the 1:160 transformer.
Those are the spec's of the calibrated FR charts that I had posted before.
Although the FR charts I had posted was with a small 5 1/4" woofer they weren't even starting to perform as such a little woofer can only produce so much due to displacement and a 650hz crossover point.
I would definitely stick with a High efficiency woofer in the longer run for any use but your Xmax is going to determine the highest levels per frequency it will be able to produce (Displacement rules!).
ESL's have been known to sail way above the woofer system in SPL once they get in their optimum frequency range.
FWIW
jer
I tried to design one for my system using spice but the more I got it to where I wanted it to be required some components that didn't justify the cost and I didn't like what it was dong to the phase response.
My First crossover was just a series capacitor and it worked okay as well with the ESL coming in above 400hz or so.
As far as cost goes, The size of the panel, Construction Technique and amount of material for the size will justify this.
Perforated metal cost's where to high for me when I started so I looked for cheaper materials and I found that plain ole' window screen was my best bet for medium to small panels and it worked great!!
Then I moved on to a more expensive method of using TIG rod although it was still much much cheaper than perforated metal.
I have been wanting to build a small set using some Lincane that you can find at Home Depot but the cost of it has gone way up through the years though it is still feasible for a small panel.
It is a bit thin to be used in a big panel but it is possible providing you have ample support for stability as it bends very easily.
When I got the bug I looked for anything and everything I could possibly use to build a set.
Being unemployed at the time, I spent about $200 on different materials and found my window screen method was the cheapest I could come up with at the time and it still stands.
I did switch to the TIG rod method later on, building some 36"x 10.5" stator's and then perfected their use with my latest little panel.
CharlieM's newest design for his big system is an extension of such a design using TIG rod and is a real testament to using the material.
And of course also mention that it is a segmented design as well!!
The electronics is pretty much a solid investment no mater the size of you panels due to the cost of the transformer's.
Reducing this cost is something that I have been working on and is my main focus.
Panel efficiency and a High Bias voltage has a lot to do with this.
It has been shown in the past that you could get away with under $100 for the interface setup, to as much as $200 or more if you want run high power going as low as 150Hz to 180Hz.
If you can find some Acoustat Interfaces cheap..Get Them !!!!
I have tested to Antek 1206 (using the 6V winding as a primary) with my Crown DC300a full power (40Vrms) and performed fine to the point of core satuartion of 360hz to 300Hz, this is a $22 transformer an you will need 4 of these for a stereo setup.
The Antex AS-1206 produced 4500Vpeak of output for just one transformer at that level (40Vrms).
My only recommendation is to stay away form the shielded types (AS-xxxx).
The shielded type is more prone to arc and short the winding's, at least this happened in my test and it also adds more to the overall stray capacitance that the transformer has.
Luckily I was able to repair it and left the shield off ( now a AN-1206) and it never failed again after that.
The part that has been tried and true by DIYer's is the 50watt model but they only make the shielded versions now.
If you wanted to go through the trouble then you can either use the shielded type and not push them or go through the painstaking process of removing the shield.
They do make a 25 watt model (AN-0206) and it is only $11 and I would think that it should be fine for small to medium powered setup, I have not tested one of these yet.
I am working on a recipe for a DIYer friendly DIY ESL transformer but I don't have the funds for the materials yet.
I wind my own primary on a selected core to get a higher transformation ratio for my smaller panels and of course I use a higher crossover frequency to suit as well.
This won't be necessary for a large panel in the 3 to 4 square foot range or larger.
It will produce plenty of sound even for a small amp in the 40 watt to 100 watt range.
It is mostly about the voltage swing (and Bias).
With the common 1:80 ratio that two of these cores offer, it gives you 9Kv p-p across the stator's with a big amp like my Crown DC300a.
That is still a lot of sound for your average panel size!!!
Providing that your are using a high bias voltage and a stator coating that won't give out on you, you would rarely need more that about 20Vrms and less for normal listening at 90db or so.
I am in no way knocking ER's products and I do owe them a lot for their inspiration of getting me to finally devulge in to this hobby all the way back to (before) 2000 or so.
As far as tools are concerned all I needed are common house tools that you would use to build a model airplane kit nothing special including a heat gun the shrink the diaphragm, the rest was all labor and patients.
If you wish to build mechanical stretcher go for it, I haven't needed one yet for my panels up to 7.5" wide, someday I will get around to making one if I start making large panels someday but I doubt personally that I will ever need one.
All of the experimenting for most part have already been done in these threads and there are only a few simple rules to follow and the main one "That I Cannot Stress Enough" is, Make sure your stator coating has sufficient thickness for the voltage range that you are planning to run your ESL's at and you won't have any issues at all when you fire them up for the First time!!
The second one of course is the Diaphragm coating and I only have one name for that "Licron" or "Licron Crystal" has been proven to work the first time and for many many many years.
I know there are other alternatives out there and it is not cheap but it works and works reliably as far as know and my own experience.
My advice has always been to get the transformers and bias supply made and then start building small panels for a start using the techniques found in these threads.
Many have done this and many I have yet to hear from again because they are to busy enjoying what they have created and like I have done.
It easy enough to do, and they are probably building different sizes to try for themselves and their friends, Who Knows!!!!
I actually know of a few that are doing this.
I know of one DIYer that you may be able to contact is "Dochungwell" he has been building his model for people and is trying to produce a kit form package as well, and maybe he can set you up, especially with a pre-made Interface unit.
If you can't get a hold of him let me know I can/will contact him for you as we have collaborated a lot in the last few years, he is located in Florida.
Anyhow as I had mentioned before, the most extreme test I had done on my little panel is when I was running about 6.5kv of bias ans had approximately 22-25KV across the stator's I had about .090 to .110 of D/S and my little panel was producing a 200Hz sine wave quite nicely and it was loud enough to scare me out of the room, above that to 1000hz and above it was unbearable and I like it loud typically 110db for me is not an issue.
I ran it like that for about 20 minutes straight until the stator coating gave out.
Again, I cannot stress stator coating enough!!!
I tried and tried to repair that panel but I never got it to that level again, and, sadly I didn't have an SPL meter at the time I did that test.
But even after the repairs I was still able to get well over +105db reliably with up to a 8Kv bias and and only 20Vpeak into the 1:160 transformer.
Those are the spec's of the calibrated FR charts that I had posted before.
Although the FR charts I had posted was with a small 5 1/4" woofer they weren't even starting to perform as such a little woofer can only produce so much due to displacement and a 650hz crossover point.
I would definitely stick with a High efficiency woofer in the longer run for any use but your Xmax is going to determine the highest levels per frequency it will be able to produce (Displacement rules!).
ESL's have been known to sail way above the woofer system in SPL once they get in their optimum frequency range.
FWIW
jer
Silly me; yes, of course
I would definitely recommend DSP, active XO and bi/tri-amping.
A low power amp indeed-but, like all First Watt amps, very sweet sounding with lots of resolving power. The F4 amp is only 25 wpc/8 ohms; 40 wpc/4 ohms with a 40 damping factor. Alas, being Class A biased, it runs hot and power hungry, thus my reluctance to biamp the system with my 2nd F4 amp-but where each
F4 amp could do 100w/per amp/ 8 ohms. So because my room is only 12 ft x 14 ft and my ears can't take average SPLs about 77db (if that much) @ 11 ft away, then wouldn't the Altec 416 be a perfect midwoofer choice?
In any case, the consensus here seems to be that even a passive 2 pole
Linkwitz filter would have too much phase shift and/or poor FR.
Don't have any experience with those, the technology looks interesting though.[/QUOTE]
It's probably good as midwoofer above 70 Hz, but why waste the space with a 15" driver in a closed box when you can use a 8" driver instead?
And above 70-80 Hz an OB dipole woofer provide enough SPL, is very easy to build, have a small footprint and integrate well with the ESL panels.
A cheap class D amp is good enough for the woofers. They have plenty of power. Save the class A for the ESL panels.
At the risk of seeming like one with tunnel vision, it wasn't only Gary Dahl's great success using the 416s in a sealed box that caught my attention. Perhaps even more, it were the particularly positive comments on them from long time contributor Lynn Olson
http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-781.html
Nutshell High Fidelity
But two questions: Could the 416s, 414s or tone tubby be used in OBs? Please check their datasheet to determine this
http://www.greatplainsaudio.com/downloads/416-8B Spec Sheet.pdf
http://www.greatplainsaudio.com/downloads/416-8B Spec Sheet.pdf
Red Alnico 12" 8 Ohm
And how far would they have to be from the corner for best response?
And above 70-80 Hz an OB dipole woofer provide enough SPL, is very easy to build, have a small footprint and integrate well with the ESL panels.
A cheap class D amp is good enough for the woofers. They have plenty of power. Save the class A for the ESL panels.
[/QUOTE]
I like the specs of that woofer but I think that their are better ones that you should consider if you are willing to spend that much in that price range.
The biggest thing I look for is a low THD and not many manufactures bother to give these particular spec's, so you have to dig for them.
I have done extensive research in this matter and have found that Dayton Reference is very very good in this area especially for the price!
Some of the MCM Alum, drivers are excellent as well for a bit cheaper in price.
But it does pay to get a quality driver should one day you want to crank it up a bit and make them sign for a while.
Some of the cheaper driver don't last very long, yet sometimes they do, it is all about reading the reviews at that point.
ESL's have very very low THD and it is good to have a woofer that can match that or at least get it as low as you can.
If you are listening at a very low level and are trying to listen to 40Hz tone and the 2nd order THD is high chances are that at one point (if it is low enough) what you will actually be hearing will be the 80Hz THD content.
I have experienced this with my own system using some cheapy drivers that I had on hand at the time.
77db is quite low and I do listen in this range as well and was when I noticed this effect.
I did some simple tests with my 8" driver and I found that an OB system (or dipole) will always have the lowest THD compared to the same driver that is in a box.
The smaller the box the higher the THD will be, this is because there is more restriction to the movement of the cone.
I measured the THD using a good microphone and used REW for that test.
The difference was nearly 10 fold at times for about 2-5%THD at 40Hz OB compared to 15% to 25% THD at 40hz in a .65 cuft. box tuned at about 24-28hz.
I put the driver in about a 1cuft sealed box and the THD was quite a bit lower (I think half to that of .65cuft.).
I didn't elaborate on making the test very scientific but I did see some interesting results.
The driver I was using was a Radio Shack Optimus PRO-CSW800 (Cat# 40-1017).
At the time that this driver was available I had found an MTX driver with the exact same specs and I believe that they are the very same driver only re-labeled, I don't remeber MTX's exact model number right now.
The reason I mention this driver is that it is the one used in my previous description using just one of me little panels.
When I got these drivers I was trying to get 16 of them to build a stereo dipole setup for my ESL system and I only ended up with 8 of them and two are bad so now I only have 6 to work with. Hmmmmmmmm.......
My very First OB system (in 1995) used six 6.5" RS poly drivers and this was the First time I had heard some quality deep bass that had no coloration.
You wouldn't think that these little drivers could do this but they did!!
I have see many use this type of setup with great results with their ESL's.
I know of one system recently that used a bunch of 6.5" in a OB line array, there are some you tube video's of that setup.
For an OB setup you need to chose your drivers by how much Xmax they have for the most part.
6.5's seem to be the most costly version these days.
I have a DIYer friend that just built a line array (although monopole) with eight 6.5" paper drivers per side that he got fairly cheap, and, he says the bass that he is getting incredibly low and clean and he doesn't even need the two dual MCM 8's that he made for his room that is the same size as yours.
He has also used the MCM's 6.5 alum drivers in a MTM setup that I designed for the top end to be used with those 2 sub cabinet's and the sound that he had got at the time totally blew him away in Sound Quality.
Now he has said that his 8 driver 6.5" line arrays are even better on the low end.
I selected the MCM 6.5" drivers he used because I had found the THD measurements somewhere.
He got those MCM 6.5's for $12-$!5 and bunch of those stacked up would give you much more speaker power on the low end and lower THD than what most single 12" drivers can produce.
I have been contemplating a system to be used in a nearfield setup or small room using a 18" long 6" wide segmented ESL with either 2 or 3 of my left over 8's in a dipole fashion.
I already know what my 9" ESL can do I am just not sure if even that many 8's will be able to keep up!! He,he,he,he
Anyhow my point is that you may consider using several smaller drivers in a dipole line array with your ESL as this would give you a smaller footprint for the size of a your room.
It would give you much more displacement for the lower end as well as a lower THD.
I am in the same predicament as you my room is only 10.5' wide on one end and 18' deep.
When I had two 12's and 10's and two 8's stacked up in each corner it took up a lot of room, but the benefit was that the sound was incredible and very low THD due to the many drivers working together.
IRC the THD was below %5 at 25hz for a 75db to 85db listening level at my listening position some 14 feet away, I still have that chart here somewhere.
If you don't mind having such a big box I would consider Dayton's they have twice the Xmax and are half the price.
The UltiMAX is an incredible woofer and even just one would be over kill for your room.
But I saw it stated in a review that someone measured it to be less than 2%THD on the low end typically lees than .5% THD on up ( it may have been the 15" version that I was thinking about), The chart was posted as well.
Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil
The RSS315HO-4 is a great woofer and is on sale right now for only $130 and only requires a 1.25cuft. box, there is a thread on this one and it is an amazing driver.
Dayton Audio RSS315HO-4 12" Reference HO Subwoofer 4 Ohm
Meanwhile for your system you might consider some of the 7" RS180's or the 8" RS225's for a very clean sound,
Dayton Audio RS180S-8 7" Reference Shielded Woofer 8 Ohm
Dayton Audio RS225-8 8" Reference Woofer
Even these have twice the excursion of your selected woofer and two per side would cost half as much as your single driver and still give you more displacement for the low end.
The classic series and the some of the DS series may be a good chose as well if you decide to try a multiple drive line array dipole.
I know that the DA175-8 7" is highly rated and I have seen the THD charts of this one over at Zaph Audio, and, there is a recent chart in the reviews as a MTM with a RS315HO, Very impressive!!!
Dayton Audio DA175-8 7" Aluminum Cone Woofer
As far as everything below 80Hz don't sweat how bad some of those curves look on the low end as you will have quite a bit of room gain for your size of room should you use a monopole woofer system.
A dipole system won't be as bad since it doesn't pressurize the room and won't excited the modes as bad (some say it doesn't excite them at all).
Just A few thing to think about,
I was so very impressed with the way my one little panel sounded with one 8" sub that I am convinced that this is all I need, even though I am planning a bigger system as well for the time I really want to rock out and play along with my guitar rig (which is quite massive in its own right).
My desktop version is what it is with a 5 1/4" woofer just because I can't fit a pair of 8's on my desk.
Being only 18" from them music sounds just fine even especially with heavy bass and drum tracks.
Even though the woofers wan't to shoot out of their frames I get no coloration or noises from them even at a level of 95db.
One day I will get some of those little Dayton subs just for them.
But being what they are (a small woofer) I can only get a peak safe level of 95db to 100db from them and be ruller flat to about 50-60hz.
of cours at a lower level this extends my low end down to the required 30-40Hz range.
Listening at the level for several hours I get ear fatigue anyhow.
They are just amazingly clean at only 85db.
But, A set like that (18" ESL and two 8's) sitting in front of me at my mixer will be something to awe at for sometime even if I don't listen to them above 90db.
Cheers!!
jer
The biggest thing I look for is a low THD and not many manufactures bother to give these particular spec's, so you have to dig for them.
I have done extensive research in this matter and have found that Dayton Reference is very very good in this area especially for the price!
Some of the MCM Alum, drivers are excellent as well for a bit cheaper in price.
But it does pay to get a quality driver should one day you want to crank it up a bit and make them sign for a while.
Some of the cheaper driver don't last very long, yet sometimes they do, it is all about reading the reviews at that point.
ESL's have very very low THD and it is good to have a woofer that can match that or at least get it as low as you can.
If you are listening at a very low level and are trying to listen to 40Hz tone and the 2nd order THD is high chances are that at one point (if it is low enough) what you will actually be hearing will be the 80Hz THD content.
I have experienced this with my own system using some cheapy drivers that I had on hand at the time.
77db is quite low and I do listen in this range as well and was when I noticed this effect.
I did some simple tests with my 8" driver and I found that an OB system (or dipole) will always have the lowest THD compared to the same driver that is in a box.
The smaller the box the higher the THD will be, this is because there is more restriction to the movement of the cone.
I measured the THD using a good microphone and used REW for that test.
The difference was nearly 10 fold at times for about 2-5%THD at 40Hz OB compared to 15% to 25% THD at 40hz in a .65 cuft. box tuned at about 24-28hz.
I put the driver in about a 1cuft sealed box and the THD was quite a bit lower (I think half to that of .65cuft.).
I didn't elaborate on making the test very scientific but I did see some interesting results.
The driver I was using was a Radio Shack Optimus PRO-CSW800 (Cat# 40-1017).
At the time that this driver was available I had found an MTX driver with the exact same specs and I believe that they are the very same driver only re-labeled, I don't remeber MTX's exact model number right now.
The reason I mention this driver is that it is the one used in my previous description using just one of me little panels.
When I got these drivers I was trying to get 16 of them to build a stereo dipole setup for my ESL system and I only ended up with 8 of them and two are bad so now I only have 6 to work with. Hmmmmmmmm.......
My very First OB system (in 1995) used six 6.5" RS poly drivers and this was the First time I had heard some quality deep bass that had no coloration.
You wouldn't think that these little drivers could do this but they did!!
I have see many use this type of setup with great results with their ESL's.
I know of one system recently that used a bunch of 6.5" in a OB line array, there are some you tube video's of that setup.
For an OB setup you need to chose your drivers by how much Xmax they have for the most part.
6.5's seem to be the most costly version these days.
I have a DIYer friend that just built a line array (although monopole) with eight 6.5" paper drivers per side that he got fairly cheap, and, he says the bass that he is getting incredibly low and clean and he doesn't even need the two dual MCM 8's that he made for his room that is the same size as yours.
He has also used the MCM's 6.5 alum drivers in a MTM setup that I designed for the top end to be used with those 2 sub cabinet's and the sound that he had got at the time totally blew him away in Sound Quality.
Now he has said that his 8 driver 6.5" line arrays are even better on the low end.
I selected the MCM 6.5" drivers he used because I had found the THD measurements somewhere.
He got those MCM 6.5's for $12-$!5 and bunch of those stacked up would give you much more speaker power on the low end and lower THD than what most single 12" drivers can produce.
I have been contemplating a system to be used in a nearfield setup or small room using a 18" long 6" wide segmented ESL with either 2 or 3 of my left over 8's in a dipole fashion.
I already know what my 9" ESL can do I am just not sure if even that many 8's will be able to keep up!! He,he,he,he
Anyhow my point is that you may consider using several smaller drivers in a dipole line array with your ESL as this would give you a smaller footprint for the size of a your room.
It would give you much more displacement for the lower end as well as a lower THD.
I am in the same predicament as you my room is only 10.5' wide on one end and 18' deep.
When I had two 12's and 10's and two 8's stacked up in each corner it took up a lot of room, but the benefit was that the sound was incredible and very low THD due to the many drivers working together.
IRC the THD was below %5 at 25hz for a 75db to 85db listening level at my listening position some 14 feet away, I still have that chart here somewhere.
If you don't mind having such a big box I would consider Dayton's they have twice the Xmax and are half the price.
The UltiMAX is an incredible woofer and even just one would be over kill for your room.
But I saw it stated in a review that someone measured it to be less than 2%THD on the low end typically lees than .5% THD on up ( it may have been the 15" version that I was thinking about), The chart was posted as well.
Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil
The RSS315HO-4 is a great woofer and is on sale right now for only $130 and only requires a 1.25cuft. box, there is a thread on this one and it is an amazing driver.
Dayton Audio RSS315HO-4 12" Reference HO Subwoofer 4 Ohm
Meanwhile for your system you might consider some of the 7" RS180's or the 8" RS225's for a very clean sound,
Dayton Audio RS180S-8 7" Reference Shielded Woofer 8 Ohm
Dayton Audio RS225-8 8" Reference Woofer
Even these have twice the excursion of your selected woofer and two per side would cost half as much as your single driver and still give you more displacement for the low end.
The classic series and the some of the DS series may be a good chose as well if you decide to try a multiple drive line array dipole.
I know that the DA175-8 7" is highly rated and I have seen the THD charts of this one over at Zaph Audio, and, there is a recent chart in the reviews as a MTM with a RS315HO, Very impressive!!!
Dayton Audio DA175-8 7" Aluminum Cone Woofer
As far as everything below 80Hz don't sweat how bad some of those curves look on the low end as you will have quite a bit of room gain for your size of room should you use a monopole woofer system.
A dipole system won't be as bad since it doesn't pressurize the room and won't excited the modes as bad (some say it doesn't excite them at all).
Just A few thing to think about,
I was so very impressed with the way my one little panel sounded with one 8" sub that I am convinced that this is all I need, even though I am planning a bigger system as well for the time I really want to rock out and play along with my guitar rig (which is quite massive in its own right).
My desktop version is what it is with a 5 1/4" woofer just because I can't fit a pair of 8's on my desk.
Being only 18" from them music sounds just fine even especially with heavy bass and drum tracks.
Even though the woofers wan't to shoot out of their frames I get no coloration or noises from them even at a level of 95db.
One day I will get some of those little Dayton subs just for them.
But being what they are (a small woofer) I can only get a peak safe level of 95db to 100db from them and be ruller flat to about 50-60hz.
of cours at a lower level this extends my low end down to the required 30-40Hz range.
Listening at the level for several hours I get ear fatigue anyhow.
They are just amazingly clean at only 85db.
But, A set like that (18" ESL and two 8's) sitting in front of me at my mixer will be something to awe at for sometime even if I don't listen to them above 90db.
Cheers!!
jer
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I don't see why not. The thing with OB is that it really helps to have a DSP to even out the frequency response down to Fs. But remember it's the frequency response in the room that's important, not the driver's/speaker's. There will be substantial room support at lower frequencies (especially in a small room).
I totally agree with jer (and many other reviewers) that Dayton Audio makes very good drivers. I use 8 RS180-4 7" Reference Woofer drivers in my woofer towers and all of them are in great condition with very similar frequency response and THD.
If I would build an OB woofer that goes even lower in freq I would probably use the UM15-22 15" Ultimax DVC Subwoofer driver in a U-baffle. I know many others are using the drivers from AE Speakers with good results.
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