I found the document I had mentioned.
It was written by G.R Koonce on 5-26-2003.
I found it a few years ago while searching very deep in the web for info on the MCM driver and these showed up in a Flicker file somewhere.
I have the whole article and I am sorting it out with all of the pictorials so that it is easier to read as it is all in a random format right now.
I am not sure if it is okay to post the whole article here but I it have if anyone is interested in it.
The whole file is about 21MB unzipped and is 12 pages long with lots of graphs and pictures for this one study as they are all Jpeg's.
But here are pages 1-4 to show the comparison of the measurements that he did for the MCM and Tangband driver along with a third that he used for this study.
The FR curves in the study between the two are so very close that they are almost the same.
I will sort those out too to show as well.
Cheers!!
jer 🙂
P.S. I can post the rest of the pages and pictorials here if a moderator gives me an Okay to do so. 😉
It was written by G.R Koonce on 5-26-2003.
I found it a few years ago while searching very deep in the web for info on the MCM driver and these showed up in a Flicker file somewhere.
I have the whole article and I am sorting it out with all of the pictorials so that it is easier to read as it is all in a random format right now.
I am not sure if it is okay to post the whole article here but I it have if anyone is interested in it.
The whole file is about 21MB unzipped and is 12 pages long with lots of graphs and pictures for this one study as they are all Jpeg's.
But here are pages 1-4 to show the comparison of the measurements that he did for the MCM and Tangband driver along with a third that he used for this study.
The FR curves in the study between the two are so very close that they are almost the same.
I will sort those out too to show as well.
Cheers!!
jer 🙂
P.S. I can post the rest of the pages and pictorials here if a moderator gives me an Okay to do so. 😉
Attachments
The MCM is so close to the Tang Band and even better in Xmax , Fs and sensitivity, My money is on the MCM but Of course Im partial all ready.... LOL but those are 3 very important factors and it passes up the Tang Band 🙂
These are the best 8" sub you will find and when running 2 in a cabinet they will compete with a 15" effortless but take up a small footprint, that's what I loved about them ( big sound little footprint ) .
Nice speaker but I still like the MCM better, for the price and quality you cant beat it .....
Yes Because when I bought mine I only paid 24.99 ea with free shipping so yes for no more than that 5-7 db is not that much I doubt you would ever turn them up to max that often to notice the difference .... 🙂 The cast frames are a nice edition but not needed for no more wattage than the MCM have.... Your FS on that silver Flute is 30.8 quite bit higher than the 24 hz of the MCM.... The QTS is higher on that SF also . Look at the chart jer. posted good because your making a big mistake on that silver flute its really not a good comparison ...
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That silver Flute looks pretty nice.
I may think about considering them for one of my small ESL builds.
Very nice and flat frequency response from them.
Do you have any THD graphs or figures for them?
I would still pick the MCM's over them for sub use though.
Using two of them like Byron has done makes up for the difference in the efficiency and with twice the Xmax to boot!
With Twice the Xmax and Twice the surface area the MCM's will be able to maintain the same SPL down to 20hz to 25hz were the Silver flute starts to drop off rather sharply at 50hz and still have nearly the same efficiency.s
For me I could careless if it it takes 100 vs 50 watts to get to a certain SPL as I have more power than most speakers can handle anyhow.
Once you get down to 30Hz or so (the lowest note on a bass guitar...B flat 30.868Hz) the limited Xmax of the silver flute is going to tear them up compared to the MCM driver.
Even though the MCM's are rated at 8mm Xmax I am sure that they can survive at least close to 10mm or even 12mm without any issues.
I do know that my cheaper made Optimus 8" sub does, although, it is rated at 10mm of Xmax.
Many speakers can handle as much as 50% more excursion than what they are rated for.....But not all.
The increase of Xmax from 5mm to 8mm alone is worth 4db to 5db more of SPL at 31Hz!!
You can compare this very easily using the Calculator link that I posted in post #24 of this thread,
http://www.diyaudio.com/forums/subwoofers/251016-cheap-sub-fantastick-results.html#post3823731
The rated Xmax as stated is typically only for its linear range and it's mechanical range can be much greater depending on the design.
The sliver Flute looks to be a very nice woofer as I have read many good things about it, But, That is what it is.....A Woofer.
This thread is about a good cost effective 8" sub woofer based on the MCM driver.
I would like to hear more about other DIYer's experiences with this driver as well.
I know that I have suggested this driver to many in the past and some have used it with great results.
I don't have any of these drivers yet, But they are in my inventory of things to get.
And, I also have just added the silver flute as well!
Thank you a.wayne for bringing this model to my attention.
Right now all I have are the RS 8" subs to work with for now.
I got the ones that I do have in 1994 and I only paid $15 a piece for them.
They were an RS close out and that was all I could get my hands on. 🙁
Keep on DIYin' !!!!
:Cheers:
jer 🙂
P.S. The Third datasheet is for the RS 8" sub Optimus CSW-PRO800 just to look at, as I had already posted the actual FR measurements that I did using this sub.
I have the As Measured Parameters here somewhere as well, and they are slightly different than what the datasheet shows.
I may think about considering them for one of my small ESL builds.
Very nice and flat frequency response from them.
Do you have any THD graphs or figures for them?
I would still pick the MCM's over them for sub use though.
Using two of them like Byron has done makes up for the difference in the efficiency and with twice the Xmax to boot!
With Twice the Xmax and Twice the surface area the MCM's will be able to maintain the same SPL down to 20hz to 25hz were the Silver flute starts to drop off rather sharply at 50hz and still have nearly the same efficiency.s
For me I could careless if it it takes 100 vs 50 watts to get to a certain SPL as I have more power than most speakers can handle anyhow.
Once you get down to 30Hz or so (the lowest note on a bass guitar...B flat 30.868Hz) the limited Xmax of the silver flute is going to tear them up compared to the MCM driver.
Even though the MCM's are rated at 8mm Xmax I am sure that they can survive at least close to 10mm or even 12mm without any issues.
I do know that my cheaper made Optimus 8" sub does, although, it is rated at 10mm of Xmax.
Many speakers can handle as much as 50% more excursion than what they are rated for.....But not all.
The increase of Xmax from 5mm to 8mm alone is worth 4db to 5db more of SPL at 31Hz!!
You can compare this very easily using the Calculator link that I posted in post #24 of this thread,
http://www.diyaudio.com/forums/subwoofers/251016-cheap-sub-fantastick-results.html#post3823731
The rated Xmax as stated is typically only for its linear range and it's mechanical range can be much greater depending on the design.
The sliver Flute looks to be a very nice woofer as I have read many good things about it, But, That is what it is.....A Woofer.
This thread is about a good cost effective 8" sub woofer based on the MCM driver.
I would like to hear more about other DIYer's experiences with this driver as well.
I know that I have suggested this driver to many in the past and some have used it with great results.
I don't have any of these drivers yet, But they are in my inventory of things to get.
And, I also have just added the silver flute as well!
Thank you a.wayne for bringing this model to my attention.
Right now all I have are the RS 8" subs to work with for now.
I got the ones that I do have in 1994 and I only paid $15 a piece for them.
They were an RS close out and that was all I could get my hands on. 🙁
Keep on DIYin' !!!!
:Cheers:
jer 🙂
P.S. The Third datasheet is for the RS 8" sub Optimus CSW-PRO800 just to look at, as I had already posted the actual FR measurements that I did using this sub.
I have the As Measured Parameters here somewhere as well, and they are slightly different than what the datasheet shows.
Attachments
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Looking at the response curve specs I don't see a driver with the efficiency claimed. It is more like closer to <80dB in the low bass region and would take 6x or more power to achieve the same spl for a given displacement. BIG difference when comparing apples to oranges and all that 🙂
Ya,I don't exactly trust MCM's measuring technique when it comes to the graph!!
Did you notice the sharp dip in the response at 40Hz!!!!
They sure could have used a bit of smoothing too, that would have helped a lot!!!
But not for the dip at 40Hz!!! 😉
Hmmmmmmm...........
As measured by the Infamous G.R. Koonce in document in post #61, it shows that the ones he tested (although 11 years ago) were right on with the catalog and he even stated that on the fourth page!!! 😉
jer 🙂
Did you notice the sharp dip in the response at 40Hz!!!!
They sure could have used a bit of smoothing too, that would have helped a lot!!!
But not for the dip at 40Hz!!! 😉
Hmmmmmmm...........
As measured by the Infamous G.R. Koonce in document in post #61, it shows that the ones he tested (although 11 years ago) were right on with the catalog and he even stated that on the fourth page!!! 😉
jer 🙂
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Dig deeper Jer .....
Its at best 84db/1w/M @1k , 3 per side should work fine ( or 3 prs) if you figure out the 40hz xover dip..
🙂
Its at best 84db/1w/M @1k , 3 per side should work fine ( or 3 prs) if you figure out the 40hz xover dip..
🙂
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These are the mini towers I run with these subs one under each tower. The towers carry 2 MCM 6.5" cast aluminum woofers # 55-3862 Increased voice coil length and magnet gap height
1.4" diameter, four layer copper voice coil
Rigid aluminum cone
Synthetic dust cap
Rubber surround
Front and rear gasket seal
Fully shielded 23.5 oz. magnet Specifications:
Power Capacity: 75W/150W RMS/peak
Sensitivity: 88dB (W/M)
Impedance: 8ohm
Re: 6.0ohm
Le: 1.90mH
Frequency response: 35Hz ~ 10KHz
Fs: 35Hz
Qts: 0.27
Qes: 0.30
Qms: 2.62
Vas: 20.05 (liters)
Xmax: 2.9mm
These are dynamite little woofers and do a fine job carrying the rest of the lower freq. 35hz-3500hz so with these you can see how the subs really shine as they are only supporting lower freq. up to 180hz ...
1.4" diameter, four layer copper voice coil
Rigid aluminum cone
Synthetic dust cap
Rubber surround
Front and rear gasket seal
Fully shielded 23.5 oz. magnet Specifications:
Power Capacity: 75W/150W RMS/peak
Sensitivity: 88dB (W/M)
Impedance: 8ohm
Re: 6.0ohm
Le: 1.90mH
Frequency response: 35Hz ~ 10KHz
Fs: 35Hz
Qts: 0.27
Qes: 0.30
Qms: 2.62
Vas: 20.05 (liters)
Xmax: 2.9mm
These are dynamite little woofers and do a fine job carrying the rest of the lower freq. 35hz-3500hz so with these you can see how the subs really shine as they are only supporting lower freq. up to 180hz ...
Attachments
G.R. Koonce wrote the old book called "Great Sound Stereo Speaker manual" and co authored a few other ones with David B. Weems as while a few articles in stereophile and such.
Great Sound Stereo Speaker Manual, David B. Weems, G. R. Koonce. (Paperback 0071348743)
It is a very informative book as I have read it before and still have a copy some where in my stack of stuff stored in the garage.
What kind of crossover causes a huge dip at 40hz for the measurement of a single sub woofer and still show 87db at 300Hz at 80db at 10hz?
This measurement should have been done without any filters to be accurate and the dips and peak in the measurement show that the room was less then optimum and smoothing should have been used.
The dip could have actually been caused be a reflection in the room from a wall or the floor or something.
This also may be the the cause of the peaks and dips in the curve as they are approximately the same intervals.
I show this exact same thing in one of my measurements of my big system when I placed the mic in the space above the speaker cabinet that is facing the corner of the room.
The reflection showed a very similar dip in my test but at about 210Hz to 220Hz.
Here is that test as shown in the middle graph on the second picture.
Only the one 2X10 was being used for that measurement.
The MCM data sheet clearly states 87DB +/- 2db, So YMMV.
The graph shows a peak of nearly 87db at 300hz but the dips in it really ruin its credibility.
Even at 80DB at 10hz room gain can also make up an extra 6db depending on the size of the room and how it has been treated.
It may not be able to compete with a Dayton RS390 or a CV Super Stroker but it looks pretty good to me for what it is ! 🙂
The experience I have had with my own RS 8" subs is pretty impressive for such a small driver.
Even though my cabin gain in my 84 Camaro may have been higher than your average room, I was able to get a few 118db to 120db transient peaks out of just two of them with a 80 watt per channel amp (a Sony Xplode) on a regular basis.
I don't listen to that HIP HOP garbage, I'm talking about the Awesomely recorded drum and bass tracks that are found on Foghat's First album.
They were clean sounding and didn't cough up any grunge doing so!!
FWIW
jer 🙂
Great Sound Stereo Speaker Manual, David B. Weems, G. R. Koonce. (Paperback 0071348743)
It is a very informative book as I have read it before and still have a copy some where in my stack of stuff stored in the garage.
What kind of crossover causes a huge dip at 40hz for the measurement of a single sub woofer and still show 87db at 300Hz at 80db at 10hz?
This measurement should have been done without any filters to be accurate and the dips and peak in the measurement show that the room was less then optimum and smoothing should have been used.
The dip could have actually been caused be a reflection in the room from a wall or the floor or something.
This also may be the the cause of the peaks and dips in the curve as they are approximately the same intervals.
I show this exact same thing in one of my measurements of my big system when I placed the mic in the space above the speaker cabinet that is facing the corner of the room.
The reflection showed a very similar dip in my test but at about 210Hz to 220Hz.
Here is that test as shown in the middle graph on the second picture.
Only the one 2X10 was being used for that measurement.
The MCM data sheet clearly states 87DB +/- 2db, So YMMV.
The graph shows a peak of nearly 87db at 300hz but the dips in it really ruin its credibility.
Even at 80DB at 10hz room gain can also make up an extra 6db depending on the size of the room and how it has been treated.
It may not be able to compete with a Dayton RS390 or a CV Super Stroker but it looks pretty good to me for what it is ! 🙂
The experience I have had with my own RS 8" subs is pretty impressive for such a small driver.
Even though my cabin gain in my 84 Camaro may have been higher than your average room, I was able to get a few 118db to 120db transient peaks out of just two of them with a 80 watt per channel amp (a Sony Xplode) on a regular basis.
I don't listen to that HIP HOP garbage, I'm talking about the Awesomely recorded drum and bass tracks that are found on Foghat's First album.
They were clean sounding and didn't cough up any grunge doing so!!
FWIW
jer 🙂
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