Coral Flat 5 t/s

ballsingtripp · 9th April 2009, 10:35 AM

Hello

I've just bought a pair of Coral Flat 5's on ebay..does anyone have any t/s parameters? I was only able to find some info on the Flat 6's. Their DC resistance or a way to measure it would be especially helpful. Unfortunately I can't afford a woofer tester at this point.

aroS3 · 9th April 2009, 12:15 PM

Not much...

ballsingtripp · 9th April 2009, 02:42 PM

Ah..still helpful, thanks!

I'm not sure if these are II's or not..

GM · 10th April 2009, 04:50 AM

FWIW, a starting point.............

Using the II's minimal specs and erroneously using Qo as Qts, then with Mo, Vas = ~12.97 L, ergo a max flat alignment is theoretically ~35.24 L tuned to ~51 Hz with a ~5.08" diameter hole if a 19 mm baffle is used.

GM

ballsingtripp · 10th April 2009, 04:31 PM

Hmm..wish I knew what I was talking about.

Is there a way to determine Vas from those specs?

GM · 10th April 2009, 07:10 PM

Not accurately, unless the Mo, Fs, effective radius specs are. As I said, I made some erroneous assumptions to derive what all I calculated, so I chose to assume Mo = Mms to calc Vas. FWIW, the calc'd Vas is within an acceptable range for the driver size, Fs.

WRT the box calc, I have some experience with the simple Qo calculations and since they're fairly accurate in the range around ~0.4 Qts, I chose to assume Qo = Qts figuring at worst, the box would be too big and/or tuned too low, so with a simple vent hole it would have plenty of tuning flexibility for optimizing it to suit your app. This assumes of course that I used the right specs for your drivers and they are accurate.

All thing considered, I doubt they're even remotely close, but I'd be surprised if you can't make the suggested box work and if turns out to be way too large (or too small, which I doubt unless driving them with a high output impedance amp) you can always make new ones, so suggest you just cobble one together from scrap or other cheap materials, even industrial strength cardboard. Just make sure there's no air leaks before each modification or the effort will be wasted.

Vas = 0.01*po*c^2*Sd^2/((2*PI()*Fs)^2*Mms)

where:

po = 1.21 Kg/m^3
c = 344.43 m/s
Sd in cm^2
Mms is in grams

Note that different programs tend to use different po, c values, so for best theoretical accuracy use the ones for the program.

Bottom line, you want accurate specs you'll have to measure them somehow, whether by someone else, use a woofer tester or do it 'long hand': http://www.diysubwoofers.org/measure.htm

GM

ballsingtripp · 11th April 2009, 12:51 AM

I'm sure these won't be the last enclosures for these drivers, and I was planning on handling it like you said too, so some experimentation is fine.

Makes sense now..thanks for the help!

GM · 11th April 2009, 01:40 AM

You're welcome!

Please let us know what you wind up with.........

GM

CFT · 15th April 2009, 04:20 AM

I am interested to know too, I have a same pair as well

Mine have Coral 5A II, 3W nomimal, 8W max....on the back. (not sure if they are the Flat 5 II either

)

I have tentatively made some mini OBs for them....eventually with active xo to be mated with 5" woofers on hand ...

ballsingtripp · 15th April 2009, 04:28 AM

Haven't actually gotten mine yet, but I hope they can handle more than 3W.

The auction said 92dB 1w/1m...

10th April 2009, 04:50 AM	#4
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	FWIW, a starting point............. Using the II's minimal specs and erroneously using Qo as Qts, then with Mo, Vas = ~12.97 L, ergo a max flat alignment is theoretically ~35.24 L tuned to ~51 Hz with a ~5.08" diameter hole if a 19 mm baffle is used. GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

10th April 2009, 07:10 PM	#6
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Not accurately, unless the Mo, Fs, effective radius specs are. As I said, I made some erroneous assumptions to derive what all I calculated, so I chose to assume Mo = Mms to calc Vas. FWIW, the calc'd Vas is within an acceptable range for the driver size, Fs. WRT the box calc, I have some experience with the simple Qo calculations and since they're fairly accurate in the range around ~0.4 Qts, I chose to assume Qo = Qts figuring at worst, the box would be too big and/or tuned too low, so with a simple vent hole it would have plenty of tuning flexibility for optimizing it to suit your app. This assumes of course that I used the right specs for your drivers and they are accurate. All thing considered, I doubt they're even remotely close, but I'd be surprised if you can't make the suggested box work and if turns out to be way too large (or too small, which I doubt unless driving them with a high output impedance amp) you can always make new ones, so suggest you just cobble one together from scrap or other cheap materials, even industrial strength cardboard. Just make sure there's no air leaks before each modification or the effort will be wasted. Vas = 0.01poc^2Sd^2/((2PI()Fs)^2Mms) where: po = 1.21 Kg/m^3 c = 344.43 m/s Sd in cm^2 Mms is in grams Note that different programs tend to use different po, c values, so for best theoretical accuracy use the ones for the program. Bottom line, you want accurate specs you'll have to measure them somehow, whether by someone else, use a woofer tester or do it 'long hand': http://www.diysubwoofers.org/measure.htm GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

11th April 2009, 01:40 AM	#8
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	You're welcome! Please let us know what you wind up with......... GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

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9th April 2009, 02:42 PM	#3
ballsingtripp diyAudio Member Join Date: Dec 2008	Ah..still helpful, thanks! I'm not sure if these are II's or not..

10th April 2009, 04:31 PM	#5
ballsingtripp diyAudio Member Join Date: Dec 2008	Hmm..wish I knew what I was talking about. Is there a way to determine Vas from those specs?

11th April 2009, 12:51 AM	#7
ballsingtripp diyAudio Member Join Date: Dec 2008	I'm sure these won't be the last enclosures for these drivers, and I was planning on handling it like you said too, so some experimentation is fine. Makes sense now..thanks for the help!

15th April 2009, 04:20 AM	#9
CFT diyAudio Member Join Date: Jul 2006	I am interested to know too, I have a same pair as well Mine have Coral 5A II, 3W nomimal, 8W max....on the back. (not sure if they are the Flat 5 II either ) I have tentatively made some mini OBs for them....eventually with active xo to be mated with 5" woofers on hand ...

15th April 2009, 04:28 AM	#10
ballsingtripp diyAudio Member Join Date: Dec 2008	Haven't actually gotten mine yet, but I hope they can handle more than 3W. The auction said 92dB 1w/1m...

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