Take it step by step. First, swap the phase on the top section (pos from the amp to neg on the speakers and neg on the amp to pos on the speakers) and leave it as-is on the bottom. This shouldn't work as a 1st order xo is, as you said, a 90 deg. shift, but I've been positively baffled by solutions that defy convention before. If no success, wire it back up normal and remove the coil. A coil can suck up a lot of power (this 25watts number is a thin air stat- who knows how much is being lost through the coil). This still probably won't get any more low bass at all, but will get you more overall output. Then, air out the brace / divider with three or four holes, each three or four inches in diameter (educated guess). This will get you some lower bass gain, with the new and exciting risk of bottoming out the MOWs.
As it was said before, this cabinet is grossly undersized for these drivers to get any low bass output. Sad but true, and I've been there before when I first dabbled in audio. I'm not optimistic that there's hope for anything short of a rebuild with a much larger bottom cab.
Friendly suggestion- you're killing yourself with numbers. Earlier on, you were calculating the volume displaced by the choke coil. It is an entirely inconsequential size to be concerned with. Bracing as well. Then referencing the power-handling of the cab...600 watts at what frequency (will x-max be breached) and for how long? Who knows, those numbers are ballpark and notoriously massaged by maufacturers. Same thing with the amp. I'll bet I could get 3000 watts out of it, but at a massive amout of distortion. Conversely, it might only give you 100 watts while keeping THD and IMD within reasonable limits. Plus, is your input signal high enough to drive it to its rated output? Again, who knows, they're just guidelines, not to live and die by. Predictions of performance are only good for controlled environments, and pro equipment's surroundings are widely varied and constantly changing. Ask yourself, is it loud enough? (don't worry about your amp's ratings) Is the range wide enough? (put away the RTA to see if you've got your 48Hz goal) And does it sound good to you? (tell your buddy that he'll need to bring his own rig because your's can't support his bass). I don't know what my GN is putting to the ground, but it stomps on Corvettes and I run alongside a guy with a Viper whenever we meet around town. "Whaddya got at the wheels?" I dunno, more than you.
As it was said before, this cabinet is grossly undersized for these drivers to get any low bass output. Sad but true, and I've been there before when I first dabbled in audio. I'm not optimistic that there's hope for anything short of a rebuild with a much larger bottom cab.
Friendly suggestion- you're killing yourself with numbers. Earlier on, you were calculating the volume displaced by the choke coil. It is an entirely inconsequential size to be concerned with. Bracing as well. Then referencing the power-handling of the cab...600 watts at what frequency (will x-max be breached) and for how long? Who knows, those numbers are ballpark and notoriously massaged by maufacturers. Same thing with the amp. I'll bet I could get 3000 watts out of it, but at a massive amout of distortion. Conversely, it might only give you 100 watts while keeping THD and IMD within reasonable limits. Plus, is your input signal high enough to drive it to its rated output? Again, who knows, they're just guidelines, not to live and die by. Predictions of performance are only good for controlled environments, and pro equipment's surroundings are widely varied and constantly changing. Ask yourself, is it loud enough? (don't worry about your amp's ratings) Is the range wide enough? (put away the RTA to see if you've got your 48Hz goal) And does it sound good to you? (tell your buddy that he'll need to bring his own rig because your's can't support his bass). I don't know what my GN is putting to the ground, but it stomps on Corvettes and I run alongside a guy with a Viper whenever we meet around town. "Whaddya got at the wheels?" I dunno, more than you.
I'm just trying to avoid royally screwing up the cab, research before I do. I sealed the entire cab with caulking so it would be hard to replace the shelf if I had to. I'm gonna switch the phase on the MOWs today and see what happens.
If that doesn't work, I think I'll try cuting the holes but leaving the xo on the MOWs just to see. Then try without.
If that doesn't work, I think I'll try cuting the holes but leaving the xo on the MOWs just to see. Then try without.
Ok, I just tried with the MOWs + - switched and I can hear the basslites more and there is more bass, not a ton, but more. I'm using a guitar that is tuned in drop Ab (Nile's Tuning) so I should be getting something.
Next I'm gonna take out the crossovers.
And does anybody have an idea where specifically to put the holes in the shelf? corners? middle?
Next I'm gonna take out the crossovers.
And does anybody have an idea where specifically to put the holes in the shelf? corners? middle?
Naw, leave your cap on the MOW's but wire a rheostat in parallel with the cap
to let a small amount of bass leak through. Play a bass note like 50Hz with your
PC sound card into it. Tune the rheostat till the MOWs move as little as possible.
Then measure that rheostat and put a fixed resistor in the rheostat's place.
That should trick the woofers into thinking the MOW's are just solid box wall.
And keep the underhung MOW coils from being pushed out out of the narrow
gap where they are most efficient.
I think the raw motor strength (BL product) of your MOWs is higher than the
Basslites. So it shouldn't have any trouble to stand its ground against being
shoved around by the woofers. But you want the woofers doing all the big
cone movements and seeing the whole box. Don't allow the MOWs to move
on the bass notes, or they will take up an unfair share of the box, and it will
seem even smaller for the real woofers.
I don't see any reason the Basslite's need a choke coil. They got plenty of
overhanging inductance already. And won't hurt nothing to let em play the
midrange up to their natural rolloff in parallel with the MOWs.
to let a small amount of bass leak through. Play a bass note like 50Hz with your
PC sound card into it. Tune the rheostat till the MOWs move as little as possible.
Then measure that rheostat and put a fixed resistor in the rheostat's place.
That should trick the woofers into thinking the MOW's are just solid box wall.
And keep the underhung MOW coils from being pushed out out of the narrow
gap where they are most efficient.
I think the raw motor strength (BL product) of your MOWs is higher than the
Basslites. So it shouldn't have any trouble to stand its ground against being
shoved around by the woofers. But you want the woofers doing all the big
cone movements and seeing the whole box. Don't allow the MOWs to move
on the bass notes, or they will take up an unfair share of the box, and it will
seem even smaller for the real woofers.
I don't see any reason the Basslite's need a choke coil. They got plenty of
overhanging inductance already. And won't hurt nothing to let em play the
midrange up to their natural rolloff in parallel with the MOWs.
The Basslites play flat to all the way to 1kHz, then peak at +7dB before rolling off at 2kHz. Now, that might not be offensive at all to some, and as I said in my previous post, to each their own with what sounds good, but I postulate that it will sound very "thick". Of course, now that the band "Nile" has been mentioned by name, thick might be just the ticket if the peak at 2kHz doesn't ruin it.
Should be unimportant exactly where they go. Have you tried playing throught the cabs with the back totally removed? Give that a shot and see how "Ramses Bringer Of War" sounds...
Thats the crux of the one box problem: With cap, the MOWs have very small
XMAX that would be routinely violated as passive radiators. And passive rads
need MUCH bigger displacement than the real driver to be effective as a port,
as they would be moving in opposite phase. Not to mention they are sprung
way too tight and tuned way too high for that to work anyhow.
If you gank MOW cap entirely, again you violate XMAX, this time by driving
them with bass directly. MOW motors are stronger than the basslites, so the
BLites would become the passives. Which isn't really a problem, except you
are also now competing with them for ownership and use of limited volume
inside the box. BLites alone could make far more effective use of that volume.
I was suggesting a compromise of cap and resistor in parallel for the MOWs.
That they respond to bass only just enough NOT to become passive radiators.
The idea is to find a neutral balance where they are effectively solid wood to
bass notes. And let the BassLite drivers have ownership of the whole box at
those frequencies (with or without ports, your choice).
I don't see any problem running the BassLites full range without added coil.
His amp is rated to handle the 8 ohm impedance over the 2K or so that
both BassLite and MOW would fire in unison. Remembering that voice coil
overhang is at least 1 or 2mH parasitic choke that all bass speakers have.
Unless they also have shorting rings that extend into the overhang, and
I doubt that applies in this case.
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Hi kenpeter,
Your idea has merit, though the MOWs motor is not much stronger than the basslite. It is your suggested way of optimizing this resistance that I would question.
Regardless, I think that the MOWs will be powerless to resist the reactive pressure from the basslites unless they are getting the full signal, then Xmax is sure to be breached.
Mounting shallow boxes to minimally enclose the MOWs will solve this but severely cut the LF performance of these drivers while giving the basslites as much of the box as possible.
No great solutions for sure. I still say that removing one of the basslites and venting the box is the best solution.
Your idea has merit, though the MOWs motor is not much stronger than the basslite. It is your suggested way of optimizing this resistance that I would question.
Regardless, I think that the MOWs will be powerless to resist the reactive pressure from the basslites unless they are getting the full signal, then Xmax is sure to be breached.
Mounting shallow boxes to minimally enclose the MOWs will solve this but severely cut the LF performance of these drivers while giving the basslites as much of the box as possible.
No great solutions for sure. I still say that removing one of the basslites and venting the box is the best solution.
Well here's what I'm thinking right now. I would consider the single basslites that's vented idea but I don't know how I would fill the 12" hole left from the driver. And I could turn the second basslites into a bass cab. But realistically I'm thinking about putting holes in the shelf and running both sets at full range/pull the crossovers
Yeah, I've just refreshed my memory of both spec sheets.
The motors are comparable 11BL vs 12BL. And both appear
to be underhung. Major diffs being XMAX, tightness of the
suspensions, and moving mass. The parasitic choke isn't as
bad as I had quoted either... All the same, my plan above
stands reasonably solid.
-----------------------------------------------------
You take away one of his BassLites, that corrects for box
tuning, but its also gonna cut into efficiency. Hows that
gonna compete with the MOW's which are already +5dB
louder??? Hoffmans iron law etc etc...
-----------------------------------------------------
I agree that separately enclosing the MOWs into a much
smaller volume would be a safer bet. But how to do that?
Make cups from the bottom of Home Despot buckets???
The motors are comparable 11BL vs 12BL. And both appear
to be underhung. Major diffs being XMAX, tightness of the
suspensions, and moving mass. The parasitic choke isn't as
bad as I had quoted either... All the same, my plan above
stands reasonably solid.
-----------------------------------------------------
You take away one of his BassLites, that corrects for box
tuning, but its also gonna cut into efficiency. Hows that
gonna compete with the MOW's which are already +5dB
louder??? Hoffmans iron law etc etc...
-----------------------------------------------------
I agree that separately enclosing the MOWs into a much
smaller volume would be a safer bet. But how to do that?
Make cups from the bottom of Home Despot buckets???
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You make a 12" blockoff plate with ports in it. I've done that before.
It'll go deep, but one basslite never gonna be as loud as two MOWs...
Worth a try.
Cheap enough anyway.
Taking out one basslite allows for reasonable tuning for that driver, increasing bass production. The MOWs will dominate the sound anyway, whether there are 1 or 2 basslites - they play in the most sensitive range of hearing and they are more efficient.
The basslite driver appears to be designed for a 80Hz. punch peak in a box of around 2cu. ft., so two of them in a vented box of about the size you have is just about right.
For a down tuned e string or a five string, a peak at 50-60Hz. is preferable.
All you really need is one guitar driver for two of these, (using a series capacitor to keep out the lows), and putting it in an open backed box on top of the other one would seem to be the easiest way of getting what your after.
rcw.
For a down tuned e string or a five string, a peak at 50-60Hz. is preferable.
All you really need is one guitar driver for two of these, (using a series capacitor to keep out the lows), and putting it in an open backed box on top of the other one would seem to be the easiest way of getting what your after.
rcw.
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