Hello,
This is my first hifi DIY speaker build, and I was hoping someone more knowledgeable in this area could look over my cabinet calculations and provide feedback. I'd like to maximize the bass response as much as possible.
Would someone who has access to a speaker simulation program calculate the frequency response of these speakers with a BIB cabinet?
The MOTH BIB cabinet seems rather small as compared to the B20 dimensions. Size for me is not an issue.
Any recommendations are greatly appreciated!
Attached is the MOTH driver specifications, and below is the BIB cabinet dimensions.
Thank you!
-David
This is my first hifi DIY speaker build, and I was hoping someone more knowledgeable in this area could look over my cabinet calculations and provide feedback. I'd like to maximize the bass response as much as possible.
Would someone who has access to a speaker simulation program calculate the frequency response of these speakers with a BIB cabinet?
The MOTH BIB cabinet seems rather small as compared to the B20 dimensions. Size for me is not an issue.
Any recommendations are greatly appreciated!
Attached is the MOTH driver specifications, and below is the BIB cabinet dimensions.
Thank you!
-David
An externally hosted image should be here but it was not working when we last tested it.
It will be smaller -you've a much lower Vas. I make basically the same size, give or take a whisker.
Greets!
Well, you inputted Vas/Qts as 0.21 ft^3/0.67 when it should have been 0.7416/0.67 respectively, so it's much larger at >9 ft^3.
Before going any farther though, you need to get them measured as the published specs aren't even in the same country as the measured specs I have, which will make it prohibitively large unless of course you don't mind anteing up for a couple of ~46 ft^3 cabs:
Re= 11.2 ohms
Le= 0.13mH
Fs= 47.3Hz
Qms= 9.6
Qes= 1.23
Qts= 1.09
Sd= 201 cm^2
Vas= 58.5 liters
Cms= 1.03 mm/N
Mms= 11 gramms
Rms= 0.34 kg/s
BxL= 5.42 N/A
SPL= 91dB
These specs in the 9+ ft^3 cab looks pretty bad, but you never can be sure till you build/audition one in-room, so as always YMMV:
GM
Well, you inputted Vas/Qts as 0.21 ft^3/0.67 when it should have been 0.7416/0.67 respectively, so it's much larger at >9 ft^3.
Before going any farther though, you need to get them measured as the published specs aren't even in the same country as the measured specs I have, which will make it prohibitively large unless of course you don't mind anteing up for a couple of ~46 ft^3 cabs:
Re= 11.2 ohms
Le= 0.13mH
Fs= 47.3Hz
Qms= 9.6
Qes= 1.23
Qts= 1.09
Sd= 201 cm^2
Vas= 58.5 liters
Cms= 1.03 mm/N
Mms= 11 gramms
Rms= 0.34 kg/s
BxL= 5.42 N/A
SPL= 91dB
These specs in the 9+ ft^3 cab looks pretty bad, but you never can be sure till you build/audition one in-room, so as always YMMV:
GM
Attachments
Updated Cabinet Calculations
GM & Hitsware, and all,
Thank you a TON for your help and thoughtful oversight.
Below are the revised cabinet calculations using GM's measured values. I had read in other professional reviews of these drivers that the measurements were different than the published specs, but could not find any other values. This was helpful.
Do these numbers look better?
-David
GM & Hitsware, and all,
Thank you a TON for your help and thoughtful oversight.
Below are the revised cabinet calculations using GM's measured values. I had read in other professional reviews of these drivers that the measurements were different than the published specs, but could not find any other values. This was helpful.
Do these numbers look better?
-David
An externally hosted image should be here but it was not working when we last tested it.
You're welcome!
Unfortunately, you didn't. The 21 L Vas is the published spec that you converted incorrectly/whatever. The measured Vas spec I posted is 58.5 L, so convert this to ft^3 using the spreadsheet's built in converter. If you don't wind up with the 46+ ft^3 Vb with the new Vas I mentioned earlier, then try again.
GM
Unfortunately, you didn't. The 21 L Vas is the published spec that you converted incorrectly/whatever. The measured Vas spec I posted is 58.5 L, so convert this to ft^3 using the spreadsheet's built in converter. If you don't wind up with the 46+ ft^3 Vb with the new Vas I mentioned earlier, then try again.
GM
Right. Sorry Greg & guys. I'm not at my best at the moment. Yeah, using those measured specs, that's one heck of a big box.
Excuse my ignorance, but the Moth driver looks to be an almost exact copy of the Lowther DX-3. Anyone used them; how much do they cost; and are they as good as Lowther ???
Thanks,
Steve M.
Thanks,
Steve M.
Sorry for coming in so late... I quickly scanned the posts... with a Qts of 1.09 does it make sense to use this driver in a BIB at all for best performance?
Is this driver still available to purchase? I am curious what the final cabinet dimensions will be.
Is this driver still available to purchase? I am curious what the final cabinet dimensions will be.
Scottmoose said:
Me neither, three times I started to post only to find a dumb-*** mistake like yours and David's, then when I thought I finally had all my facts right, you had me wondering what I'd still managed to miss/get wrong.
Anyway, hope whatever's ailing you goes away quick. I'm counting on you young 'guns' to keep me on the 'straight and narrow' as I spiral down the 'drain' of senility that at least for now has no cure.
GM
Steve M said:
'Close' only counts in horse shoes and hand grenades and this driver's effective motor strength is only a fraction of the Lowther's, so it takes a huge cab to get any LF gain BW out of it and in theory is under-damped enough to seriously compromise at least its mids clarity and yet most reviews I read said that its mids/HF was quite good with one well respected DIYer claiming it took a Fostex F200A to best it, high marks indeed!
Regardless, at $119 retail it was a bargain IMO and at its $89 sale price a steal and was seriously frustrated I couldn't take advantage of it. The fact that you rarely see them for sale used says a lot too. Mounted on an OB with a sub system to fill in the bottom octaves may be an inexpensive entry level ultra-fi rig.
Anyway, I forget who bought out the stock when they folded and sold them off, but they claimed they were planning a re-issue, hopefully with one that at least matched or bested the published specs, but for whatever reason it didn't happen AFAIK.
GM
GM said:
You're still sharper than me Greg. 😉 Will be in touch soon.
I always liked the look of the Moth unit,as they're quite pretty & look like they were decently built, though I never heard a great deal about them, other than a couple of on-line reviews of complete speakers. FWIW, Spectrumaudio in Germany still look like they've got a few kicking around at £150Euros a pop, which kind of clobbers their value a bit. Still, not a bad price for a driver if it's as good as it's rep. suggests.
As far as I know, David's are the pair I gave away at Burning Amp, and they
are not available new anywhere. They were indeed very good, a cut below the
Lowther PM6a's.
😎
are not available new anywhere. They were indeed very good, a cut below the
Lowther PM6a's.
😎
" ...a cut below the Lowther PM6a's."
That's good to know, so it won't be threatening my DX-3 or PM2A-Ticonals too soon then. Always on the look out for alternatives though ...
Regards,
Steve M.
That's good to know, so it won't be threatening my DX-3 or PM2A-Ticonals too soon then. Always on the look out for alternatives though ...
Regards,
Steve M.
Good Cabinet Recommendations for MOTH?
These are indeed the pair of MOTH's Nelson VERY graciously donated to my DIY cause!
Perhaps a BIB enclosure is not the best design for the drivers?
What would be a good suggestion for a cabinet type to consider for the MOTH's?
Thank you,
-David
These are indeed the pair of MOTH's Nelson VERY graciously donated to my DIY cause!
Perhaps a BIB enclosure is not the best design for the drivers?
What would be a good suggestion for a cabinet type to consider for the MOTH's?
Thank you,
-David
- Status
- Not open for further replies.