Question about "Bi amping"

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heavybdrums
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Question about "Bi amping"

#1 Post by heavybdrums » Tue Aug 28, 2018 5:23 pm

My current system of 4 T39s and 2 Dr250s I would assume is considered a bi amped system. Using a DBX Driverack (active crossover) to send the LF content (45-120 hz) to the QSC GX7 and then to the T39s, and all else above the 120 HP filter to the QSC GX5, and then to the two DR 250s.
The question is would it be of any benefit acoustically to bi amp the DR 250s with the Driverack configured to a 3 way system and bypass the passive crossover in them?
The DR 250s are loaded with Deltalite II 2510 and the 20 element melded array.
If there is some benefit, what would the active crossover parameters be for the 2510 and melded array, and the limiter settings?
4x WH8 delta pro
2x WH10 Deltalite 2510
4x Dr250 Deltalite II 2510
8X Titan 39 3012lf, 28"
4X Tuba 60 W/ lab 15
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Bill Fitzmaurice
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Re: Question about "Bi amping"

#2 Post by Bill Fitzmaurice » Tue Aug 28, 2018 5:34 pm

No benefit at all. You use bi-amping mainly to provide sufficient power to each pass band. The melded array by dint of being a high impedance load draws practically no power.

CoronaOperator
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Re: Question about "Bi amping"

#3 Post by CoronaOperator » Tue Aug 28, 2018 5:53 pm

I'll repeat what has been said here before and my experience agrees with it:

Bi-amping has some merits for a direct radiator woofer / horn top cab. Because they are so in-efficient, direct radiator cabs get run balls to the wall at max power to get a decent spl. That leads to clipping the amp which produces harmonics in the higher frequencies. Since the horn tweeter is really efficient, that distortion becomes very audible. Bi-amping those cabs avoids that. Mid horns like in the DR250 are efficient so they don't have that problem. Also direct radiators need about 800 W to compete with only 200 W in a mid horn like the DR250. That heats up the voice coil which increases resistance in the coil which alters the passive crossover's parameters which changes the tone of the cab as the volume level increases. Horns don't have that problem either. There might be something to say about time aligning the highs to the mids by bi-amping, the cabs sound subjectively bright due to the highs arriving before the mids in the DR250. I'd do it in a high fidelity home system, for PA use having highs that cut through the crowd noise isn't such a bad thing. It would take another amp, 4 conductor speaker cable, and some in depth tuning to get it right. I originally wanted to try it out on my DR250's, I never got around to it because they sound really good as they are.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Bruce Weldy
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Re: Question about "Bi amping"

#4 Post by Bruce Weldy » Tue Aug 28, 2018 6:46 pm

heavybdrums wrote:
Tue Aug 28, 2018 5:23 pm
My current system of 4 T39s and 2 Dr250s I would assume is considered a bi amped system.
To clear up the semantics......

Bi-amping has always referred to separately powering two drivers (woofer and tweeter) in the same box. So, no, you aren't bi-amped, you are running a two-way system.

With three drivers in a single box utilizing separate power amps, it's a tri-amped box. Large, passive JBL line arrays used to run this way....

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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heavybdrums
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Re: Question about "Bi amping"

#5 Post by heavybdrums » Tue Aug 28, 2018 6:49 pm

Thanks bill, have read a bunch on bi amping and made me ask.
Corona I concur that the DR250s sound great as they are, just wanted to be sure I wasn't missing out on something that could be gained by bi amping them, and apparently I am not.
I do not feel the melded piezio array is overly bright in pa applications, I find that it is one of the things that puts my system above a lot of others.
Thanks guys
4x WH8 delta pro
2x WH10 Deltalite 2510
4x Dr250 Deltalite II 2510
8X Titan 39 3012lf, 28"
4X Tuba 60 W/ lab 15
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Bill Fitzmaurice
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Re: Question about "Bi amping"

#6 Post by Bill Fitzmaurice » Tue Aug 28, 2018 9:00 pm

Bruce Weldy wrote:
Tue Aug 28, 2018 6:46 pm
To clear up the semantics......
Bi-amping has always referred to separately powering two drivers (woofer and tweeter) in the same box. So, no, you aren't bi-amped, you are running a two-way system.
Splitting hairs. Bi-amping is using two amps, along with an active crossover, to cover the spectrum, tri-amping three amps, quad-amping four. I bet there are even some penta-amped systems out there. Time was it was done with different drivers sharing the same cabinet, before the advent first of separate bass bins, then of subwoofers. Whether the drivers are in one box or two/three/four/five the electronics are the same, so I'm comfortable calling a separately power sub and top a bi-amped system.

Bruce Weldy
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Re: Question about "Bi amping"

#7 Post by Bruce Weldy » Wed Aug 29, 2018 11:14 am

Bill Fitzmaurice wrote:
Tue Aug 28, 2018 9:00 pm
Bruce Weldy wrote:
Tue Aug 28, 2018 6:46 pm
To clear up the semantics......
Bi-amping has always referred to separately powering two drivers (woofer and tweeter) in the same box. So, no, you aren't bi-amped, you are running a two-way system.
Splitting hairs. Bi-amping is using two amps, along with an active crossover, to cover the spectrum, tri-amping three amps, quad-amping four. I bet there are even some penta-amped systems out there. Time was it was done with different drivers sharing the same cabinet, before the advent first of separate bass bins, then of subwoofers. Whether the drivers are in one box or two/three/four/five the electronics are the same, so I'm comfortable calling a separately power sub and top a bi-amped system.
I don't disagree, but when you use the term bi-amp, most guys will think you are talking about a top with two drivers and two amp channels, and not considering the sub.

At least, that's where my brain goes if someone tells me they are bi-amping.

And yeah, there was a guy here in town who ran his JBL line array system 5 way......thought he could do a better job on the crossovers in the JBLs than JBL did.....so three way up top, added kick bins, and subs..... viola! Penta-amped.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Lustyik
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Location: Hungary

Re: Question about "Bi amping"

#8 Post by Lustyik » Wed May 22, 2019 7:49 am

I know this is an old topic, but I would have a question here.

I have an OT12 (2512 and NSD CD). NSD "over-performs" the mid speaker. I use Driverack auto EQ for correction. Sound is perfect, no problem.

I will use Jack Lite with 2512 and 2xNSD. I suppose I should use more EQs to reduce high frequencies. Too much EQ can cause a phase problem I've learned here.
When using a 3-way system, Driverack allows you to set different volume levels for low, medium, and high channels.
Driverack would send lower signal to the amp of the high channel than to the mid.This way I could balance the volume differences between CDs and 2512. I still have to use EQ, but not for the volume correction. I assume less EQ would be enough.
Am I correct?
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

Bruce Weldy
Posts: 6709
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Location: New Braunfels, TX

Re: Question about "Bi amping"

#9 Post by Bruce Weldy » Wed May 22, 2019 8:47 am

Lustyik wrote:
Wed May 22, 2019 7:49 am
I know this is an old topic, but I would have a question here.

I have an OT12 (2512 and NSD CD). NSD "over-performs" the mid speaker. I use Driverack auto EQ for correction. Sound is perfect, no problem.

I will use Jack Lite with 2512 and 2xNSD. I suppose I should use more EQs to reduce high frequencies. Too much EQ can cause a phase problem I've learned here.
When using a 3-way system, Driverack allows you to set different volume levels for low, medium, and high channels.
Driverack would send lower signal to the amp of the high channel than to the mid.This way I could balance the volume differences between CDs and 2512. I still have to use EQ, but not for the volume correction. I assume less EQ would be enough.
Am I correct?
I didn't go look at the plans, but off the top of my head - I believe the Jack with two NSD drivers specifies 16ohm versions. That reduces the power to them, keeping them equal in output to a single 8 ohm.


However, the NSD is no longer being made....and they discontinued the 16 ohm version a couple of years ago. You'll need to go with another driver.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

CoronaOperator
Posts: 1603
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Question about "Bi amping"

#10 Post by CoronaOperator » Wed May 22, 2019 9:31 am

Bruce Weldy wrote:
Wed May 22, 2019 8:47 am
I didn't go look at the plans, but off the top of my head - I believe the Jack with two NSD drivers specifies 16ohm versions. That reduces the power to them, keeping them equal in output to a single 8 ohm.
My plans quote two 8 ohm NSD drivers wired in series to give a 16 ohm load. It also states to use the higher output 3012ho or Delta Pro 12 due to the higher sensitivity of the NSD's.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Bruce Weldy
Posts: 6709
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Question about "Bi amping"

#11 Post by Bruce Weldy » Wed May 22, 2019 11:11 am

CoronaOperator wrote:
Wed May 22, 2019 9:31 am
Bruce Weldy wrote:
Wed May 22, 2019 8:47 am
I didn't go look at the plans, but off the top of my head - I believe the Jack with two NSD drivers specifies 16ohm versions. That reduces the power to them, keeping them equal in output to a single 8 ohm.
My plans quote two 8 ohm NSD drivers wired in series to give a 16 ohm load. It also states to use the higher output 3012ho or Delta Pro 12 due to the higher sensitivity of the NSD's.
I stand corrected.......I believe you are right.

Bottom line though - you can't get those drivers anymore.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

ACUA
Posts: 347
Joined: Sun Sep 25, 2016 6:21 pm

Re: Question about "Bi amping"

#12 Post by ACUA » Wed May 22, 2019 8:34 pm

I like control, often I over complicate the system trying to gain control and I find my self always tweeking the settings. It’s likely I dial my self out as much as I dial it in :noob: ... I like the active setup. I have control over all of it. But I bet that the passive filters in the plans are just fine, I just like the tinker-ability. I would be inclined to biamp that rig for tinkering purposes but my money says I would not be able to improve it any. By me biamping my rig it allows me to claim ownership of that part of the system and fuels my ego. A double edged sword as the more complicated a system the more that can go wrong and the harder to fix, a simple system easy setup less room for error. When I’m home all I wanna do is adjust parameters and play when it’s a paid gig I want it simple and sturdy. Biamping requires more cables an amp and more settings to set. Passive keeps it all nice and neat and passive is more sturdy/ reliable it seems. You can’t loose programmed settings over a power outage with a passive system..
Advanced concepts underground audio

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Bill Fitzmaurice
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Re: Question about "Bi amping"

#13 Post by Bill Fitzmaurice » Wed May 22, 2019 9:00 pm

An L-Pad costs a lot less than an amp. :mrgreen:

CoronaOperator
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Re: Question about "Bi amping"

#14 Post by CoronaOperator » Wed May 22, 2019 9:11 pm

Bill Fitzmaurice wrote:
Wed May 22, 2019 9:00 pm
An L-Pad costs a lot less than an amp. :mrgreen:

...but with a DBX Venue 360, another amp, an ipad or laptop, and a router and lots of cables you can adjust it from your seat!
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

ACUA
Posts: 347
Joined: Sun Sep 25, 2016 6:21 pm

Re: Question about "Bi amping"

#15 Post by ACUA » Wed May 22, 2019 11:02 pm

I’m thinking that if I ever build a big enough line array rig I may put pots in a few of the bottom cabs to help the situation
Advanced concepts underground audio

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