Same 2 Cabs But Different Ohm Drivers

Is this amp OK?
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jimbo7
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Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Same 2 Cabs But Different Ohm Drivers

#1 Post by jimbo7 »

I currently have an 8ohm Eminence BP102 in my T24. Can I build another with the 4ohm version and run them on the same amp (each having their own channel)? Will it be problematic using different ohm drivers at the same time and getting them to match up sound-wise (seperated or v-plated)?

I searched but didn't find a direct answer.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

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DJPhatman
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Location: Warren, MI
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Re: Same 2 Cabs But Different Ohm Drivers

#2 Post by DJPhatman »

I don't recall the 4 Ohm BP102 being a recommended driver. But, I may have missed it. Happens a lot these days. :oops:

I would recommend you use the same driver in a second. If you are going to use them together, they should be the same. Just my thinking, though.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

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Bill Fitzmaurice
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Re: Same 2 Cabs But Different Ohm Drivers

#3 Post by Bill Fitzmaurice »

jimbo7 wrote:I currently have an 8ohm Eminence BP102 in my T24. Can I build another with the 4ohm version and run them on the same amp (each having their own channel)?
Why? If you use another 8 ohm then you can run both on one channel, and not have to waste a channel.

jimbo7
Posts: 849
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: Same 2 Cabs But Different Ohm Drivers

#4 Post by jimbo7 »

Bill Fitzmaurice wrote:Why? If you use another 8 ohm then you can run both on one channel, and not have to waste a channel.
Yeah I know that subject's been beatin to death, but I can get one cheap. And the fact horns perform better in groups, plus I currently have more amps than speakers.

I'm just wondering if they'll behave together.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: Same 2 Cabs But Different Ohm Drivers

#5 Post by Grant Bunter »

jimbo7 wrote:
Bill Fitzmaurice wrote:Why? If you use another 8 ohm then you can run both on one channel, and not have to waste a channel.
Yeah I know that subject's been beatin to death, but I can get one cheap. And the fact horns perform better in groups, plus I currently have more amps than speakers.

I'm just wondering if they'll behave together.
The BP102 4 ohm is displacement limited to (IIRC) 26V. The 8 ohm limit is 35V.
So, you could run them on different amp channels and achieve displacement limiting, but only if you have the DSP to have different sub outputs for each channel. If that amp isn't 2 ohm capable/stable, you can only run one 4 ohm loaded cab on the other channel.

Another option would be to build dual loaded 4 ohm BP's and wire them in series, in cab. That cab would then have a limit of 52V, if your amp is capable of that.

Funnily enough, 2 x T39's, BP loaded with 8 ohm drivers, at the max 10" driver width of 20", would have a smaller footprint, smaller pack space, around the same output, as 4 x 24" wide T24's.
If you used the two you have in your T24's now, driver cost would be $0

Yes, your new T24's could be V plated, and yes, in terms of response, the cabs would play nice together...
Last edited by Grant Bunter on Sun Mar 05, 2017 3:33 am, edited 2 times in total.
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

jimbo7
Posts: 849
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: Same 2 Cabs But Different Ohm Drivers

#6 Post by jimbo7 »

I decided to pass on the idea thanks to Grant. I could've got a new/used bp102-4 cheap, but after learning the 8ohm version has the same power, decided against it. Now I know that whatever design I build next (*cough..T45), I'll stay with 8ohm drivers and pair them on one channel.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

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