bass speaker help

[phase_accurate]

This Monacor is the exact driver that I am using for my compact practicing amp (Bruellwuerfel for those of German mother-tongue).
It doesen't have very high efficiency but it goes reasonably loud with a 100 Watts amp at home. And I don't think that I ever used more than half of the linear x-max with the 100 Watts amp near clipping (with the low B of my six string !). The end-configuratiuon will use a 150 Watt amp or maybe slightly more.
The box is about 20 liters and has a tunig slightly above 50 Hz.

It is a nicely-made driver (probably P-Audio) that makes a sturdy impression.

I already wondered how it would fare in a 2x8 or 4x8 configuration. Although a 2x10" with neo drivers (Beyma 10 Mw/Nd or how it was called) would be lighter than such a 4x8and probably be more powerful as well.

Regards

Charles

 

[tinitus]

This Monacor is the exact driver that I am using for my compact practicing amp..............

I already wondered how it would fare in a 2x8 or 4x8 configuration.

Charles

allright

I also tried to calculate with two of them, and got a pretty nice result, in theory
But price begin to catch up on bigger drivers

But wouldnt there be phase issues with double drivers
I mean, in hifi you get all sorts of phase issues from two drivers
But we see lots of designs with 4 drivers, or more

do the basic rules for speaker design not count, when used for guitar
I do know the frequency response may need to be be very different, with a rising response
But the general rules of phase ought to be the same, whether its hifi or pro speakers
Or am I missing something

 

[voltcontrol]

MTH30 (accompanied by a widebander) an option perhaps?
The recommended Precision Devices 12SB30 (and if you put it in a proper TH it can kill you ) driver costs a bit over 100 E.

The (nice indeed) Monacor driver discussed costs about 50E as far as I know, if anyone could find it for less I'd also be very interested.

 

[phase_accurate]

The physics of speaker design are the same ones for instrument speakers than they are for Hi-Fi speakers but the targets are not the same.
Loudness is definitely a factor - irregular off-axis response is (for many manufacturers) less of an issue. But there ARE manufacturers of instrument speakers who do care about such things. Especially in the area of bass reproduction you will find products that are multiway systems with a single driver per frequency range (actually small specialised PA systems).

You are of course free to use a crossover (active or passive) when using two woofers and decouple one of them towards higher frequencies in order to increase LF power handling, and compensate for ** and rising driver rersponse.

It could be difficult to find the same driver elsewhere since it seems to be manufactured specially for Monacor. But I think it is just a question of time until more of this kind appear.
The price is not such a problem for me because there is not a large choice of cheap and decent drivers in my home country anyway. :-(

Regards

Charles

 

[chris661]

Or am I missing something

Sounds like it.

The drivers will have a more direct effect on each other if they have wide dispersion. An 8" driver will beam from pretty low (1kHz?). With less and less dispersion, the higher frequencies are more likely to sum than cancel, as they'll all be going the same way.

Oh, and it all adds to the sound of it anyway...

Chris

 

[tinitus]

Dont worry, its only to get started and it was gratis

But it does have output for exstern speaker, which could be a nice woofer

 

[chris661]

Handy. Looks like a guitar amp though...

I expect that switching off the internal speaker when you add extra would be a good feature...
I put 2x 1/4" jack sockets on the back of my combo, and soldered a plug onto the onboard speaker. That way, I can choose to unplug the internal speaker, and power 2 external cabinets. You can get so much more volume that way.

Chris

 

[tinitus]

Handy. Looks like a guitar amp though...

Chris

yep, it is
my friend used it when he needed a microphone

I reckon a series cap on speaker terminals will do

 

[chris661]

It'll be a big cap...

I expect adding a back to give a sealed design would be better. It would certainly stop excursion getting too much.

Chris

 

[tinitus]

ahh, no problem

you seem to have overlooked that I will use extern woofer
"onboard" guitar speaker will be used as midrange/tweeter only
maybe crossed around 1khz or so

I could aslo completely disconnect onboard speaker
and connect a tweeter compression driver/horn instead

lots of options
but will such small 15watt guitar amp manage to drive a 15" pro woofer

 

[chris661]

Yeah, I overlooked that.

I see no reason why the amplifier won't driver a 15" woofer. Just need to ensure the efficiency is high enough. My little Tripath amplifier (approx 15w/ch) will push my 12" Eminence woofer loud enough to cause annoyance in the vicinity.

It would give an interesting sound, having a guitar speaker as a mid-high.

 

[tinitus]

hey, I may have a design now, and quite cheap too, and could hold other interesting options for its use

 

[chris661]

Hmmm, slot loading the bottom driver could be fun - it would act as an acoustic crossover, so you're unlikely to hear much distortion until the VC smacks the back plate.

You could spend a lot of time playing with a router, trying to get them integrated.

 

[tinitus]

Hmmm, slot loading the bottom driver could be fun - it would act as an acoustic crossover

thats what it is, a 6.order

I have done some more calculations, especially on front port on low woofer
and it all fits very nicely
low tuning is around 40hz in 80liter
front 20-30liter and 2 slot ports of 20mm x 100mm, gives upper 105hz roll off
and according to calculation upper midwoofer roll off around 100hz in 15liter closed

 

[chris661]

You'll need some LF protection on that woofer, if you're gonna play it loud. I dunno how much resistance the ports will give to unloading.

Still, looks cool. How does the FLH simulate?

 

[tinitus]

Still, looks cool.

Thanks Chris

Calculation says 115db+, within linear 4-5mm Xmax limit of both drivers, down to 40-45hz
But you are right, about a filter
if used professionally I would make it fully active, with DSP eq

But it probably never leave my "living room"

and if building two of them with additional tweeter/horn, it could also be used for party, everyday musik, PA, DJ, etc

sure, for bass guitar only, one driver in a much smaller box would do fine
but I expect this bigger design will have much more "volume", a bigger sound
unfortunately I dont have the time to do it right now
and Im still waiting for my Moses bass neck

 

[chris661]

Thanks Chris

Calculation says 115db+, within linear 4-5mm Xmax limit of both drivers, down to 40-45hz
But you are right, about a filter
if used professionally I would make it fully active, with DSP eq

Impressive, especially given the driver count. Eminence drivers have very little Xmax, but the Xmech is pretty high. What sort of SPLs when you really push? Say, 2mm clear of Xmech...

But it probably never leave my "living room"

and if building two of them with additional tweeter/horn, it could also be used for party, everyday musik, PA, DJ, etc

sure, for bass guitar only, one driver in a much smaller box would do fine
but I expect this bigger design will have much more "volume", a bigger sound
unfortunately I dont have the time to do it right now
and Im still waiting for my Moses bass neck

I think making this into a PA would be a good idea. Here's an idea. Instead of the Delta 12, use a Beta 12CX, as you'll be able to get a point-source mid-high, instead of a tweeter sat on top.

Chris

 

[tinitus]

I think making this into a PA would be a good idea. Here's an idea. Instead of the Delta 12, use a Beta 12CX

yes, I have thought about it, using Beyma 12XANd, but cost is higher
older Beyma 12XC30 is cheaper
10" 10XC25 might work too
raised cost's may not be more than with addditional tweeter

anyway, someone posted something like ..... believe me, you dont want very high frequency for bass guitar
I dont know, maybe it becomes a bit sensible to string noise, distortion, etc, and gets more difficult to play

maybe less good for home hifi, but for PA it ought to work with a couple of slot tweeters or piezos
mounted in upper waveguide horn baffles
with a switch, and adjustable att, and still only xo on tweeter

a more hifi quality oriented version would need additional horn on top, and proper 2way xo, crossed much lower

 

[chris661]

Well, here's an idea.

Make a full-range PA, and add some clever equilisation in the pre-amp section (a graphic eq would be good), for the bass guitar input.

 

[tinitus]

hey, here's two new woofers
well, I can get them locally, with no shipping cost

but I cant decide between them
the 12" seems ok with a closed box
the 15" seems suited for open design like H-frame

any thoughts ?

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