Acoustic Cross Helper Woofer

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Einric

Einric

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So...Here is my thought.
I have a 2 way RS100-8 w/ DC28F on a 5000hz first order.
I really like the way they sound but obviously the bass is a little lacking.
My idea is to take a DA175 that I have on hand and put it in a 4th order bandpass enclosure to create an acoustic crossed helper woofer.
The RS100-8 will be enclosed in a 6" PVC pipe cap to create a .06 cuft enclosure behind it.
This models to make an acoustic crossover at about 110hz which is great for this little woofer.
The only question is should I connect the DA175 in Series or Parallel?
I'm thinking parallel since I have a 4Ω stable amplifier.
Any thoughts or recommendations?
 

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T

tinitus

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yes, its been done before
even commercially
from what I know there will be a port ressonance higher up
could be dealt with by a smallish inductor
dont know if its 1khz, below or above ?
but I think it will be there
or can it be avoided completely, I dont know
 
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
Einric said:
I really like the way they sound but obviously the bass is a little lacking.
My idea is to take a DA175 that I have on hand and put it in a 4th order bandpass enclosure to create an acoustic crossed helper woofer.
Click to expand...

just remember, your woofer should not have very low Qts
I think from minimum 0.3 and up to maybe just above 0.35
if lower it might work better in 6th. order

ach, Dayton Da175 with Qts of 0.58
big magnet, and still weak motor
not too good

put it in a BIG closed box ;)
probably cant be too big
you will then need xo, ofcourse :eek:
 
Einric

Einric

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I will probably be running a pair of LM4780's for 4 channels with two volume controls.
This will allow me to "Gain Match" the 3db lower DA175 to the RS100.
Also it will keep my LM4780's running a nice safe 8Ωish load.
An L-Pad will handle the higher sensitivity DC28F to match the RS100.

Worst case I will just turn the thing into a .95 cuft 2-Way with the 2500 LR2, the ports would be replaced for a 31hz tuning.
The rear of this cabinet will be removable.
I am currently gluing the cleats on to support the flush rear panel.
 
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Einric

Einric

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The sim on the first post shows the DA175 in BP4 w/ an RS100 in a .87 QTC Sealed sub-enclosure. I will hopefully have the first one ready to test today.

Since this is very experimental I am building just one to begin with.
I have both chassis built but I will not flush mount the front drivers until after testing.
If testing goes well I will cut off the front baffle and install a new one with chamfers.
Once that is complete I will apply my raw Afromosia Qtd veneer and then flush mount the drivers.

If testing does not go well I will replace the baffle and create a 2-Way with the DA175 following the alignment from Zaph's BAMTM design.

I have a friend that will come over to run a few passes w/ REW to get some measurements.
 
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Einric

Einric

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Joined 2011
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Initial Thoughts

The bass is there and the ports are moving an insane amount of air.
I'm wondering if the two 1.05" ports are not choking the woofer.
The bass is not very loud compared to the other drivers (I figured I'd find that).
The RS100 is still reaching X-Max when cranked even though it is in a .065 cu. ft. sealed enclosure....I have a pair of 250uf NPE's that might solve that.
The biggest problem I have with it is the bass lacks punch and definition.
I may just resort to Plan B and build a 2-Way with the DA175 & DC28F.

???Any Thoughts???
 
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