I've designed and build a bass guitar cab (photo attached). Its not behaving the way I wanted. I'm looking for suggestions.
Its a sonotube, covered with carbon fiber. Looks cool as hell. The idea was a little hot dog with high output, flat down to 32 hz for those 5 string bass guitars, lightweight, easy to carry into a small club for those gigs where the pa was too small to carry bass.
The carbon fiber and sonotube idea worked well - its strong, light, beautiful.
First I used a Eminance delta 12 LF. I'm using bass box pro for the design software. No crossover on the woofer, and a high pass on the piezo tweeter. Sounded fine until you turned it up and then it farted badly.
Then I changed the driver to an Eminance Omega pro 12, adjusted the port length per bass box pro, and it was better, but still had a bad sound when you smacked a low string.
Then I added an 18 db per octave high pass filter with a corner frequency at 40 hz (yes, - expensive coils). And it still farts!
How can I get driver control down low? Am I expecting too much of a 700 watt driver? It farts even with a 400 watt amp on the low e or b string.
It just does not put out enough clean low end. Maybe a single 12 was a bad idea. Is there a 12 out there that will handle more, work ported, and carry 32-2000? turned down it sounds beautiful, rich smooth, flat - but the big low transients of a string seem to be too much. I could make it a closed design - but I can't easily reduce the cabinet volume. Maybe I could close the port and stuff the hell out of the cab to get a sealed-like behavior - but then I've wasted a lot of space - and effeceincy.
I suppose I can measure the actual output (I have full measurement capability) to see if the driver is up to spec - but I expected eminance's second biggest 12 to be more or less bombproof in this application. Anyway, since I'm grasping at straws - all creativity is welcome.
😡
Its a sonotube, covered with carbon fiber. Looks cool as hell. The idea was a little hot dog with high output, flat down to 32 hz for those 5 string bass guitars, lightweight, easy to carry into a small club for those gigs where the pa was too small to carry bass.
The carbon fiber and sonotube idea worked well - its strong, light, beautiful.
First I used a Eminance delta 12 LF. I'm using bass box pro for the design software. No crossover on the woofer, and a high pass on the piezo tweeter. Sounded fine until you turned it up and then it farted badly.
Then I changed the driver to an Eminance Omega pro 12, adjusted the port length per bass box pro, and it was better, but still had a bad sound when you smacked a low string.
Then I added an 18 db per octave high pass filter with a corner frequency at 40 hz (yes, - expensive coils). And it still farts!
How can I get driver control down low? Am I expecting too much of a 700 watt driver? It farts even with a 400 watt amp on the low e or b string.
It just does not put out enough clean low end. Maybe a single 12 was a bad idea. Is there a 12 out there that will handle more, work ported, and carry 32-2000? turned down it sounds beautiful, rich smooth, flat - but the big low transients of a string seem to be too much. I could make it a closed design - but I can't easily reduce the cabinet volume. Maybe I could close the port and stuff the hell out of the cab to get a sealed-like behavior - but then I've wasted a lot of space - and effeceincy.
I suppose I can measure the actual output (I have full measurement capability) to see if the driver is up to spec - but I expected eminance's second biggest 12 to be more or less bombproof in this application. Anyway, since I'm grasping at straws - all creativity is welcome.
😡
Attachments
Am i correct in saying you have tuned your port to ~8hz below Speaker resonance?/
this will make linearity worse.
Loudspeaker xmax on these speakers isnt amazingly high.Especially due to being PA/PRO units ,and at the worst they would be tuned at or above resonance,minimising excursion requirements.
Are you using a plate amp with preset EQ?
What is the modeled response on bassbox pro?
Cheers
this will make linearity worse.
Loudspeaker xmax on these speakers isnt amazingly high.Especially due to being PA/PRO units ,and at the worst they would be tuned at or above resonance,minimising excursion requirements.
Are you using a plate amp with preset EQ?
What is the modeled response on bassbox pro?
Cheers
One thing first: Although square boxes are usually more convenient to handle for gigging -- this is one of the damnbloodycoolest looking bass-boxes I have seen so far !
Estimated from the look of the box its volume is between 2 and 3 cubic foot, isn't it ? For best power handling this is too large for a driver with a Vas of slightly less than 2 cubic foot. Use a smaller volume and a slightly higher tuning and sacrifice some of the low end output (while gaining some mid-bass with this low Qts).
Just keep in mind that many commercial bass-boxes start to roll off between 60 and 80 hz.
Instead of lowering the volume: Why not use a lowpass-filtered driver of the same type on the backside (push-push configuration) ? This would give you 6 dB more headroom and also mean the same as halving the volume !
Regards
Charles
Estimated from the look of the box its volume is between 2 and 3 cubic foot, isn't it ? For best power handling this is too large for a driver with a Vas of slightly less than 2 cubic foot. Use a smaller volume and a slightly higher tuning and sacrifice some of the low end output (while gaining some mid-bass with this low Qts).
Just keep in mind that many commercial bass-boxes start to roll off between 60 and 80 hz.
Instead of lowering the volume: Why not use a lowpass-filtered driver of the same type on the backside (push-push configuration) ? This would give you 6 dB more headroom and also mean the same as halving the volume !
Regards
Charles
Xmax is definitely your worst enemy here. Most Eminence drivers have a small Xmax figure, and will easily exceed this with as little as 50W at low frequencies, even if the driver is rated at 800W.
If you want to keep with Eminence, model the Lab12 to see if it is suitable in your box (tube? "box" implies square corners ...). It's large Xmax will allow much higher power down on the low string.
Cheers
If you want to keep with Eminence, model the Lab12 to see if it is suitable in your box (tube? "box" implies square corners ...). It's large Xmax will allow much higher power down on the low string.
Cheers
The port area is way too small, so you have power compression at high power and excursion. Chances are that you're exceeding XMax as well trying to use a drivers with a high Fs in a small ported box. You may get what you want with a port no less than 6 inches diameter; once you model how large the box will have to be you'll see that what you have is way too small.
Some of the other posts regarding box size are correct, if you're using the speakers for guitar. The suggestion of a LAB12 is on track, but in a ported or sealed box the SPL is at least 10dB shy of what you need. Bottom line, the drivers are not the problem. The cabinet is.
There are two boxes here, DR12 and DR12a, that you can use your existing drivers in that will do what you want them to:
www.billfitzmaurice.com
Some of the other posts regarding box size are correct, if you're using the speakers for guitar. The suggestion of a LAB12 is on track, but in a ported or sealed box the SPL is at least 10dB shy of what you need. Bottom line, the drivers are not the problem. The cabinet is.
There are two boxes here, DR12 and DR12a, that you can use your existing drivers in that will do what you want them to:
www.billfitzmaurice.com
I would remove that expensive passive filter and make a direct connection to the amp. Then use a super-steep *active* LPF inside the amp, tuned just below the B string.TheoM said:
more
Charles - thanks - it is beautiful .... that's why I want to make it sound great. The next version I will do exactly as you suggest - higher tuning, smaller box. The bandpass idea (push push) is interesting. I'll try to model it. I thought about a speaker on the back - good use of space, and it physically balances the box.
All - I am using Bass Box Pro. The box is a little over 3 cubes. I used "suggest" and it gave me the port (4"x6.2) dimensions. link to screenshot above. The response in theory looked great.
Centuari - your guess is right. I * Failed * to take the power response seriously - but now that I look at it, yes, at 50 hz, never mind 32, it won't hardly take 50 watts. However, is there a driver that will take this punshment? In the current box, the only variables I have to play with are the port length (or close it), the driver, the stuffing and the crossover. Basically, carbon fiber is tough to cut, and the baffles and epoxied on. re-rouoting them in place would be a huge pain.
Bill - Bass Box Pro gave me the port dimension. I realize the box is the problem - but I' trying to find a fix for this one before I go to the next version. (The carbon fiber process is expensive and messy so I don't want to trash the box). I will model the lab12.
For the next version I was also thinking about a coax 15 with a rear port - or even mounting a coax 18 directly to the tube. The idea was to use the strength and symetry of a tube in a cab design. Also, I will use Kevlar instead of carbon fiber. (Its cheaper, not as strong, and bright yellow). I wanted a front port for punch - phase alignment.
BTW another cool thing about this design is that at 23 inches long, if you put it against a wall there's a quarter-wave cancellation in the nasty-coloration range (150) that tends to counteract the effect of putting it against a wall.
Also, we call it the "Bush Pusher" because at its first gig, the bass player had women ride it (it was before we had handles) while he played low notes. Apologies if this offends anyone - but we thought it was funny - and so did my wife. 🙂.
Charles - thanks - it is beautiful .... that's why I want to make it sound great. The next version I will do exactly as you suggest - higher tuning, smaller box. The bandpass idea (push push) is interesting. I'll try to model it. I thought about a speaker on the back - good use of space, and it physically balances the box.
All - I am using Bass Box Pro. The box is a little over 3 cubes. I used "suggest" and it gave me the port (4"x6.2) dimensions. link to screenshot above. The response in theory looked great.
Centuari - your guess is right. I * Failed * to take the power response seriously - but now that I look at it, yes, at 50 hz, never mind 32, it won't hardly take 50 watts. However, is there a driver that will take this punshment? In the current box, the only variables I have to play with are the port length (or close it), the driver, the stuffing and the crossover. Basically, carbon fiber is tough to cut, and the baffles and epoxied on. re-rouoting them in place would be a huge pain.
Bill - Bass Box Pro gave me the port dimension. I realize the box is the problem - but I' trying to find a fix for this one before I go to the next version. (The carbon fiber process is expensive and messy so I don't want to trash the box). I will model the lab12.
For the next version I was also thinking about a coax 15 with a rear port - or even mounting a coax 18 directly to the tube. The idea was to use the strength and symetry of a tube in a cab design. Also, I will use Kevlar instead of carbon fiber. (Its cheaper, not as strong, and bright yellow). I wanted a front port for punch - phase alignment.
BTW another cool thing about this design is that at 23 inches long, if you put it against a wall there's a quarter-wave cancellation in the nasty-coloration range (150) that tends to counteract the effect of putting it against a wall.
Also, we call it the "Bush Pusher" because at its first gig, the bass player had women ride it (it was before we had handles) while he played low notes. Apologies if this offends anyone - but we thought it was funny - and so did my wife. 🙂.
Re: more
As Bill mentioned, the ouput of the Lab12 will be lower due to its low sensitivity. Another driver that may work well is the Beyma 12LX60 - it has a good compromise between Xmax and sensitivity, but I believe the distribution of these is poor in the States.
Cheers
TheoM said:
As Bill mentioned, the ouput of the Lab12 will be lower due to its low sensitivity. Another driver that may work well is the Beyma 12LX60 - it has a good compromise between Xmax and sensitivity, but I believe the distribution of these is poor in the States.
Cheers
The driver isn't the problem; the cabinet is. While it's visually stunning, unfortunately you designed it using a box program that's optimized for consumer level performance, not pro-sound, so consumer level performance is all you're going to get. Using a single twelve just won't do for extreme SPL low frequency applications without horn loading. If you're going to stick with a sealed box or reflex design it will take multiple drivers to do it.
How about a sealed cab? You should be able to size the thing and stuff it to get the freq response you want and solve the excursion problems of a percussive attack. Closed cabs generally give tighter sound too - less flap, damped by air pressure as they are - maybe not as "loud" but if you have a mother bass amp it should work ok. I also think the 12 is probably too small, depending on the volume you need. A 15 or maybe even and 18 would be better if you need to play loud.
Cheers.
Cheers.
BillFitzmaurice said:
I can't agree fully on this. There are a few manufacters that are
using this program to give you an analysis of the speaker's
performance when used in a box. And, they are steered
toward Pro Audio.
I do agree on the cabinet causing the problem. However,
this box was designed wrong for the application being used.
The box resembles moreover those car tube subs. And, I
would imagine, offering the same kind of performance, in
which wasn't the goal.
Although, the idea was very noble, there are certain things
to take into factor the designer overlooked.
Great driver, wrong application
The HL10a is a fabulous driver, I recommend it for use in my Tuba 24 pro-sound sub, but it's the wrong driver for this application. It's optimized for horn loading, not vented box use, and is a sub-dedicated design that is not intended for use above 300 Hz.
The HL10a is a fabulous driver, I recommend it for use in my Tuba 24 pro-sound sub, but it's the wrong driver for this application. It's optimized for horn loading, not vented box use, and is a sub-dedicated design that is not intended for use above 300 Hz.
reply
Well the Eminence site says the HL-10 can be used in small sealed boxes,small reflex boxes and horn loaded boxes.
And if u say its just a sub driver well then u could add something like the Eminence Legend B102 guitar speaker or Delta 10 above that.
Well the Eminence site says the HL-10 can be used in small sealed boxes,small reflex boxes and horn loaded boxes.
And if u say its just a sub driver well then u could add something like the Eminence Legend B102 guitar speaker or Delta 10 above that.
Yes, it can. But if you read beyond the large type you 'd see that the HL10a has a sensitivity of 87dB, 10dB less than a B102, so your proposed two-way would have a very interesting response curve to say the least. The HL10a requires horn loading to achieve the sensitivity required for pro-sound use.
Thanks all - and my "learnings".....
"If you don't get success you get experience". As a researcher, I fail for a living, but usually not so spectacularly....
What I learned here:
1)Don't ever ignore power response.
2) Ports need area to avoid power compression, and this factoid isn't in my models, but seems obvious if you think about moving air. Also, all the pro sound boxes I own (I have 4 PA systems, renkus, jbl, EAW, and home made) have large port areas relative to driver size - now I know why.
3) Horn loading is the answer to the age old question "how do I get the most bass out of the smallest box ,per power".
4) Beauty is as beauty does (a reminder)
5) There is no driver that will make the bp2300 sound right in its current configuration. I will consider rerouting for a 15 and using a rear port as a fix to the box - its still to big to run sealed, methinks, at 3 cubes, because I have to cover the full spectrum. Sealed mid woofs don't have enough low to support bass guitar, and true subs have no low mids. (I tried a Lab12 - I live 30 minutes from parts express - and it sucked too - as predicted by Bill - very ineffecient and still farted with a gk 200 watt amp - althoug it made a lot of bass, the 300-1000 was bad)
Anyway, I'm extremely grateful for all the help here. I've made several sets of diy speakers that sounded great for hi fi, and measured very flat, so I was a bit arrogant. (slap, slap ,slap). ... but I'm better now. ... ted.
"If you don't get success you get experience". As a researcher, I fail for a living, but usually not so spectacularly....
What I learned here:
1)Don't ever ignore power response.
2) Ports need area to avoid power compression, and this factoid isn't in my models, but seems obvious if you think about moving air. Also, all the pro sound boxes I own (I have 4 PA systems, renkus, jbl, EAW, and home made) have large port areas relative to driver size - now I know why.
3) Horn loading is the answer to the age old question "how do I get the most bass out of the smallest box ,per power".
4) Beauty is as beauty does (a reminder)
5) There is no driver that will make the bp2300 sound right in its current configuration. I will consider rerouting for a 15 and using a rear port as a fix to the box - its still to big to run sealed, methinks, at 3 cubes, because I have to cover the full spectrum. Sealed mid woofs don't have enough low to support bass guitar, and true subs have no low mids. (I tried a Lab12 - I live 30 minutes from parts express - and it sucked too - as predicted by Bill - very ineffecient and still farted with a gk 200 watt amp - althoug it made a lot of bass, the 300-1000 was bad)
Anyway, I'm extremely grateful for all the help here. I've made several sets of diy speakers that sounded great for hi fi, and measured very flat, so I was a bit arrogant. (slap, slap ,slap). ... but I'm better now. ... ted.
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