hi everyone,
I'm about to embark on a diy construction of a bass guitar cabinet. it's going to be a 2x12" vented cabinet with a tweeter.
now, I've chosen the following speakers:
18sound 12W500
(site seems to be down at the moment, you can see the specs anyway here)
or maybe a pair of these:
FaitalPro 12PR300
Monacor SP12-200PA
although I'm more sold towards the 18sound drivers, as they seem to have better efficiency, the FaitalPro look nice, with a decent xmax and a flat response, but I'm actually after a "bright", voiced response, and the 2k peak in the response seems to be similar to what I actually try to dial in on my amp. the monacor drivers seem nice as well, with a touch more bass (at least, on the simulations) compared to the 18sound drivers. I'm quite undecided between the two, actually.
and no, please, no eminence drivers, it's kind of a requirement for my project, since SO MANY cab manufacturers use eminence drivers, and I'm actually looking for something that may be maybe a bit different
cabinet size, I'm thinking at 120 L @ 45Hz tuning frequency, as it seems a good compromise for all the drivers I've been considering (actually, the cabinet will be quite large, but it's not a big deal). the cone excursion actually exceeds xmax at 350W, but considering I won't be using the cabinet to output sine waves, but bass guitar, I think I'm quite safe (as a rule of thumb, I'm considering the average excursion of the first 4 harmonics of a given note, namely the low E @ 41Hz, and trying to keep this average value under xmax, but then again, I'm not after perfect linearity, and actually I like speaker break-up, many bass players overdrive their speakers far beyond their xmax as a choice)
do you think it's a sensible project? or are there areas for improvement? obviously the cabinet will be braced and I'll put foam on the sides (most projects I've seen avoid putting much foam in vented cabinets, opting for padding just the sides or the rear panel). regarding foam, is it true that it "artificially" increases speaker volume by about 20% (meaning that, in practice, a 120 L simulated cab will have to be 25 L smaller)?
as a last question, I was thinking of installing a fabric dome tweeter, but most fabric dome tweeters seem to have low sensibility (around 93-94dB SPL), are there any fabric dome tweeters around with a higher efficiency?
thanks
I'm about to embark on a diy construction of a bass guitar cabinet. it's going to be a 2x12" vented cabinet with a tweeter.
now, I've chosen the following speakers:
18sound 12W500
(site seems to be down at the moment, you can see the specs anyway here)
or maybe a pair of these:
FaitalPro 12PR300
Monacor SP12-200PA
although I'm more sold towards the 18sound drivers, as they seem to have better efficiency, the FaitalPro look nice, with a decent xmax and a flat response, but I'm actually after a "bright", voiced response, and the 2k peak in the response seems to be similar to what I actually try to dial in on my amp. the monacor drivers seem nice as well, with a touch more bass (at least, on the simulations) compared to the 18sound drivers. I'm quite undecided between the two, actually.
and no, please, no eminence drivers, it's kind of a requirement for my project, since SO MANY cab manufacturers use eminence drivers, and I'm actually looking for something that may be maybe a bit different
cabinet size, I'm thinking at 120 L @ 45Hz tuning frequency, as it seems a good compromise for all the drivers I've been considering (actually, the cabinet will be quite large, but it's not a big deal). the cone excursion actually exceeds xmax at 350W, but considering I won't be using the cabinet to output sine waves, but bass guitar, I think I'm quite safe (as a rule of thumb, I'm considering the average excursion of the first 4 harmonics of a given note, namely the low E @ 41Hz, and trying to keep this average value under xmax, but then again, I'm not after perfect linearity, and actually I like speaker break-up, many bass players overdrive their speakers far beyond their xmax as a choice)
do you think it's a sensible project? or are there areas for improvement? obviously the cabinet will be braced and I'll put foam on the sides (most projects I've seen avoid putting much foam in vented cabinets, opting for padding just the sides or the rear panel). regarding foam, is it true that it "artificially" increases speaker volume by about 20% (meaning that, in practice, a 120 L simulated cab will have to be 25 L smaller)?
as a last question, I was thinking of installing a fabric dome tweeter, but most fabric dome tweeters seem to have low sensibility (around 93-94dB SPL), are there any fabric dome tweeters around with a higher efficiency?
thanks
My 2 cents: you seem to be thinking about it as a sub + tweeter project. A bass cabinet is most definitely not a sub. You need a LOT more clean upper end, and it doesn't need to go as low as a sub. Also, you point out that commercial cabs use Eminence drivers, but fail to mention that they use Emininence bass guitar drivers, not just PA drivers as you are looking for. If you want something different, that's fine, but be prepared for disappointment if you haven't thought of this yet and taken it into account. Also, you haven't given details on the tweeter and crossover, so it's hard to comment on the whole picture.
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Just remember that the Xmax of the Faital is P-P
In your sim it will be half of that
btw, theres a couple of Beyma SM series 12" with quite good Xmax(+/-), and cheap
My choise will still be PrecisionDevices PDN.15BR40, +/-8mm Xmax, and a cheap compression driver
previous plan was to mate it with PDN.12MH25
but it gets complicated, and expencive
In your sim it will be half of that
btw, theres a couple of Beyma SM series 12" with quite good Xmax(+/-), and cheap
My choise will still be PrecisionDevices PDN.15BR40, +/-8mm Xmax, and a cheap compression driver
previous plan was to mate it with PDN.12MH25
but it gets complicated, and expencive
actually, I'm actually trying to AVOID a sub+tweeter cabinet. I've specifically chosen a pair of 12" drivers that are more suited for a PA top, not subwoofers, since bass drivers are more similar to mid-woofers than to subwoofers. the 18sound drivers have an adequate xmax of 4mm (keep in mind that many cabs mount drivers with a much lower xmax, OTOH the Eminence Delta 12's xmax is only 2.5mm, and it's a driver that many DIYers use in their cabinets), but at the same time the predicted response is quite "bass-shy" (compared to a sub, at least), since the f3 is around 65Hz, moreover, the frequency response of the drivers reaches 3-4K with ease. in fact, the 12W500 look very similar (to me, at least) to the Eminence Delta 12s, but with a greater xmax.
I'm going to center the crossover frequency for the tweeter at around 3.5KHz, I'm not sure about the slope, maybe 12dB/octave is enough?
are you sure? it doesn't seem peak-to-peak to me
Yeah, there are more efficient domes, called compression drivers...
Slightly more helpful answer, even though not dome in any way:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-360
Much bigger than looks in the picture, at least size of a softball.
If you got money to throw at it...
http://www.usspeaker.com/beyma tpl150-1.htm
I suggest you drop the 2x12 plan, get you an Emenince DeltaPro 15.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-512
If there's any other model or off-brand that bright? I've not found any.
In Karlson K15 cabinet (plans 1955 Radio Electronics) will destroy all.
Ask Freddi if you need build details. BK115 might be smaller option.
Pair of 12's costs more, weighs more, all other factors being similar.
Slightly more helpful answer, even though not dome in any way:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-360
Much bigger than looks in the picture, at least size of a softball.
If you got money to throw at it...
http://www.usspeaker.com/beyma tpl150-1.htm
I suggest you drop the 2x12 plan, get you an Emenince DeltaPro 15.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-512
If there's any other model or off-brand that bright? I've not found any.
In Karlson K15 cabinet (plans 1955 Radio Electronics) will destroy all.
Ask Freddi if you need build details. BK115 might be smaller option.
Pair of 12's costs more, weighs more, all other factors being similar.
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are you sure? it doesn't seem peak-to-peak to me
FaitalPRO - Neodymium Professional Drivers
look in electrical specifications
winding depth 12.5mm
magnetic gap depth 8mm
thats 4-5mm P-P Xmax
and equals 2-3mm +/- Xmax
Well, you've thought this out, that's good
You have some other comments to think about too, so I guess the only thing I would add is forget the dome tweeter, that's just begging for problems, I would go with even a piezo before that, and I would cross over higher than 3.5 KHz for sure, especially if you're only planning a HP and no LP.I was looking for a fabric dome tweeter as I've never had the chance to use one and I've been told they have a very pleasant, natural and "soft" response, compared to compression drivers which can sound harsh, keep in mind I'm going to use lots of distortion and effects through the tweeter as well. I was looking at a Ciare PT383: CIARE - Produzione speakers, woofer, tweeter, driver e car audio (you can find it under "tweeter"), I've read great things about it.
as for the single 15" instead of the double 12"s, I'm actually after a 2x12" configuration. yes, I know that from a "hi-fi" point of view, there's nothing to gain and much to lose from a double 12 inch speaker, but I actually like the response of the 12" drivers, punchy yet warm, on bass guitar. considering that there are very few 12" cabinets for bass, and they're all expensive, I decided to fill this void on my own
anyway, any recommendation for a tweeter? I'd prefer to stay among european products.
as for the single 15" instead of the double 12"s, I'm actually after a 2x12" configuration. yes, I know that from a "hi-fi" point of view, there's nothing to gain and much to lose from a double 12 inch speaker, but I actually like the response of the 12" drivers, punchy yet warm, on bass guitar. considering that there are very few 12" cabinets for bass, and they're all expensive, I decided to fill this void on my own
anyway, any recommendation for a tweeter? I'd prefer to stay among european products.
Not from hi-fi standpoint. I play bass.
I like domes, but none loud enough for what you want to do with it.
From a dispersion standpoint, slot tweeter is the next best thing.
And slot tweeter is better match for your power and efficiency.
I like DeltaPro12 and own many, extremely similar spec to what you
want to use. I tell you to use DeltaPro15, cause it weighs less than
2x12, and better mate with Karlson enclosure.
Why Karlson? Cause you say dome, and that implies even dispersion.
Both the 12" you specify, and the 15" I would suggest, have rising
response and beaming polar pattern. Terrible direct radiator match
to dome or slot tweeter. But Karson is an indirect radiator, and will
disperse from its front slot much more similar to tweeter you want.
Not so much worry where you and/or mic stand on or off axis...
Anyways, much easier to fit 15 in Karlson than 2x12, I've tried...
There is no neodymium with bandwidth of DeltaPro15, else I'd go
something Neo. Unfortunately they all seem to chose the next
bigger 3" coil former... Heavier coil isn't helping this application...
And let me repeat it again:
Why Karlson? Cause you say dome, and that implies even dispersion.
European Mfg, maybe Celestion offers something like DeltaPro15?
They tend toward the bright MI side, good in this circumstance.
Beyma also makes a slot tweeter (they are both copies of JBL), but
more expensive than Selenium (metal vs plastic), and crosses higher.
http://www.usspeaker.com/beyma CP21F-1.htm
How bout BN15-300S? Thats neo with the smaller 2.5" voice coil!
http://professional.celestion.com/bass/orange/index.asp
I like domes, but none loud enough for what you want to do with it.
From a dispersion standpoint, slot tweeter is the next best thing.
And slot tweeter is better match for your power and efficiency.
I like DeltaPro12 and own many, extremely similar spec to what you
want to use. I tell you to use DeltaPro15, cause it weighs less than
2x12, and better mate with Karlson enclosure.
Why Karlson? Cause you say dome, and that implies even dispersion.
Both the 12" you specify, and the 15" I would suggest, have rising
response and beaming polar pattern. Terrible direct radiator match
to dome or slot tweeter. But Karson is an indirect radiator, and will
disperse from its front slot much more similar to tweeter you want.
Not so much worry where you and/or mic stand on or off axis...
Anyways, much easier to fit 15 in Karlson than 2x12, I've tried...
There is no neodymium with bandwidth of DeltaPro15, else I'd go
something Neo. Unfortunately they all seem to chose the next
bigger 3" coil former... Heavier coil isn't helping this application...
And let me repeat it again:
Why Karlson? Cause you say dome, and that implies even dispersion.
European Mfg, maybe Celestion offers something like DeltaPro15?
They tend toward the bright MI side, good in this circumstance.
Beyma also makes a slot tweeter (they are both copies of JBL), but
more expensive than Selenium (metal vs plastic), and crosses higher.
http://www.usspeaker.com/beyma CP21F-1.htm
How bout BN15-300S? Thats neo with the smaller 2.5" voice coil!
http://professional.celestion.com/bass/orange/index.asp
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Beyma actually makes a 100db hornloaded dome tweeter
http://www.beyma.de/fileadmin/seiten/download/pdf/Beyma_professional/2007-M_rz-SMC2012N_1_.pdf
and monacor/stageline have a couple of cheap options
MONACOR INTERNATIONAL
agina con particolari dei prodottianyway, I thought a "harsh/rough" tweeter would be of no concern with bass guitar, would it
well, I only considered fabric dome tweeters because I've read they're "smooth-sounding", I repeat, I've never tried a cab with a fabric dome tweeter before (there are very few cabs that mount them, for example the Accugroove cabs, but I've never tried them and I'm not really interested in them anyway), and considering I keep the tweeter quite attenuated anyway (I'm not into slap, tapping, etc. I only like a bit of "sparkle" on top, my Ashdown cab has a very "quiet" tweeter so it's on full but on most cabs I attenuate the tweeter by 10-15dB) I thought I might go for it.
by the way, both fabric dome tweeters that I was considering, the Ciare one and a cheaper SICA one, 80W RMS for 25€ approx. highpassed at 4kHz, 12dB/octave, are not exactly an investment and I'm prepared to potentially waste money.
but if you tell me that dome tweeters are going to be obliterated by the woofers and, in practice, useless and ineffective, I guess I'll go with a compression driver. but is it really necessary to mount a horn on the tweeter, or can it be mounted without a horn? tweeter-wise, I am completely ignorant.
I was thinking of designing the enclosure myself: direct radiation, vertical mounting instead of horizontal (so to achieve a better horizontal dispersion) offset from center axis (I've read that placing drivers at the middle of the baffle is detrimental since it introduces standing waves, so... OK, I'll mount them more to the side), ports at the front. but as I said before, how do I have to modify my calculations when adding padding inside the cabinet? do I have to make it bigger or smaller than nominal?
anyway, I thought a "harsh/rough" tweeter would be of no concern with bass guitar, would it
it actually is, since tweeters in bass cabs only reproduce very high harmonics but mostly fret and string noise, and pick attack (which I all like, that's why I want a tweeter, but on the other hand, I don't want it to be TOO much), besides, very efficient tweeters become a nightmare with distortion, since distorted bass through a tweeter is simply awful, harsh and very unmusical.
that horn-loaded beyma... isn't its power rating too low? I know that high frequency content is not that much, but 15W AES doesn't really seem enough to me, my current cab mounts a 50W tweeter and I've already blown one once
ps. sorry for the third post in a row, but I'm still waiting for being enabled to post immediately and edit my posts
I understand the phase issues with woofers and tweeters overlapping on a certain range, but I'm going to cross the tweeter quite high anyway, I was thinking of 3.5-5kHz range with a 12dB/octave slope, anyway, I'm open to suggestions, let's just say that my primary concern, of course, is the bass and mid region, the treble region is an added plus
I understand the phase issues with woofers and tweeters overlapping on a certain range, but I'm going to cross the tweeter quite high anyway, I was thinking of 3.5-5kHz range with a 12dB/octave slope, anyway, I'm open to suggestions, let's just say that my primary concern, of course, is the bass and mid region, the treble region is an added plus
100db may not be sensitive enough, considering 15W power limitation!
Won't survive long against 102db 600W, unless crossed absurdly high.
Remembering that 99+99=102
This whole project will be power limited by what blows dome tweeter.
Don't even need worry xmax of 12's or 15... Wired to survive, you will
mostly be hearing a lightbulb. Dome loaded by a hard horn won't sound
like "soft dome" anyway. If you can hear it at all over the midbass..
Why I suggested the slot tweeter was next best sounding, next most
similar dispersion to dome, much much louder, and dirt cheap if you go
with the Selenium.
Won't survive long against 102db 600W, unless crossed absurdly high.
Remembering that 99+99=102
This whole project will be power limited by what blows dome tweeter.
Don't even need worry xmax of 12's or 15... Wired to survive, you will
mostly be hearing a lightbulb. Dome loaded by a hard horn won't sound
like "soft dome" anyway. If you can hear it at all over the midbass..
Why I suggested the slot tweeter was next best sounding, next most
similar dispersion to dome, much much louder, and dirt cheap if you go
with the Selenium.
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ps. sorry for the third post in a row, but I'm still waiting for being enabled to post immediately and edit my posts
done
boneless - I would consider the Morel CAT 378 or MDT 37. It's a shallow horn around vented fabric dome with 93-94dB sensitivity and pretty good power handling. How often are tweets in bass cabs padded down, any way? This might be all the treble you need.
saw it here too, with some reviews: Morel CAT 378 1-1/8" Soft Dome Horn Tweeter | Parts-Express.com (I have no commercial interest)
Oh yeah, it's rebuildable too...
saw it here too, with some reviews: Morel CAT 378 1-1/8" Soft Dome Horn Tweeter | Parts-Express.com (I have no commercial interest)
Oh yeah, it's rebuildable too...
-9db less efficent than the proposed 2x12 pair? 200W would sound like 25W.
You can't pad a tweeter up unless you bi-amp, and I can't imagine padding
the 12's down to match. But whatever... You want dome? Go get you some.
Dome can't be efficient direct radiator, cause it doesn't have enough surface
area compared to the moving mass. So you horn load, OK... But you can only
add so much load before the dome can't be "soft" anymore or it'd collapse.
Now it has basically become a compression driver. Works even better if you
turn it round and add a phase plug. There may be exceptions, Selenium D250-X
midrange compresion driver appears to be a forward dome with no plug? Just me
looking into the throat, havn't taken apart to confirm. I could be entirely wrong.
Once you add the horn and harden the dome to survive the additional load?
Then what? Its not the same sounding anymore. But thats what it takes to
keep up with MI application. A soft dome simply will never be loud enough.
Trade efficiency for watts or vice versa. SPL limit is about surface area and
the soft material. It will cave before doing what you are asking. And no mfg
puts a motor behind it bigger than will cave the dome. So Watts are small,
or efficiency is poor, or dome is hardened and horn loaded, take your pick.
Before you chase dome any further, investigate the phenolic ring radiator and
slothorn combo. JBL knew what they were doing, and Selenium cloned it good.
I own this, I've play'd it, this will do exactly what is promised.
You can't pad a tweeter up unless you bi-amp, and I can't imagine padding
the 12's down to match. But whatever... You want dome? Go get you some.
Dome can't be efficient direct radiator, cause it doesn't have enough surface
area compared to the moving mass. So you horn load, OK... But you can only
add so much load before the dome can't be "soft" anymore or it'd collapse.
Now it has basically become a compression driver. Works even better if you
turn it round and add a phase plug. There may be exceptions, Selenium D250-X
midrange compresion driver appears to be a forward dome with no plug? Just me
looking into the throat, havn't taken apart to confirm. I could be entirely wrong.
Once you add the horn and harden the dome to survive the additional load?
Then what? Its not the same sounding anymore. But thats what it takes to
keep up with MI application. A soft dome simply will never be loud enough.
Trade efficiency for watts or vice versa. SPL limit is about surface area and
the soft material. It will cave before doing what you are asking. And no mfg
puts a motor behind it bigger than will cave the dome. So Watts are small,
or efficiency is poor, or dome is hardened and horn loaded, take your pick.
Before you chase dome any further, investigate the phenolic ring radiator and
slothorn combo. JBL knew what they were doing, and Selenium cloned it good.
I own this, I've play'd it, this will do exactly what is promised.
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...didn't realize he had decided on the main drivers yet. It all depends on application and how loud the rig ultimately has to play. If he is considering 2x12 already then my assumption is this is not for arena rock, maybe like small venue/recording/jazz. And with a 97dB-ish setup I suspect this little hi-fi tweet could keep up OK. I have never heard of a tweeter motor "caving in" a soft dome.
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