Working on new build, need amp advice

Is this amp OK?
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nortonw3
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Joined: Tue Mar 08, 2022 1:26 pm

Working on new build, need amp advice

#1 Post by nortonw3 »

I’ve always wanted to build a system to be able to take to festivals for renegade late night sets, and I’ve finally gotten started. I’m working on 4 tuba 45’s, and 2-4 dr280’s. For the tubas I will be going with the eminence bp102 drivers. I’m on a fairly tight budget and I’m building the speakers as I can acquire the parts so it’s going to take some time to finish the build (I’m ok with that) I guess my question for the forum is since I’m on a budget, what amps do you recomend? How many do I need to run this system with the appropriate amount of overhead/redundancy. I’m in tech sales so I know how important overhead and redundancy are. I also plan on building a portable rack/flight case to carry all the amps and other gear I need ti run the system.

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Seth
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Re: Working on new build, need amp advice

#2 Post by Seth »

I'd like to propose a few modifications to your current plan.

The least expensive top is the DR200 and 2-4 would have no problem keeping up with 4-8 or more T45's. DR200's can be built for less than $200.

In the T45's, you may consider using a budget friendly 12" (such as a Delta 12LFE) instead of the BP102. This would allow you to get them going for about the same cost and also leave the door open to upgrade to premium drivers in the future if the need arises.

Third, if you plan to use them primarily outdoors, you'll get more useable output with Titans.

And finally, an answer to the question you actually asked... if you stick with your current plan, a single inexpensive 2ohm stable amp with built in DSP and about 100-150wpc will do just fine if you're okay with mono. Even a used Behringer NU1000DSP would do well with that setup. Really, anything in that price range will be fine to get started.

At that power level, I'd personally feel comfortable running limiters that are in DSP amps. However, the right thing to do is to buy an outboard DSP unit (such as dbx Driverack). It's something we typically consider mandatory gear and you should really add it to your needed gear list. Be aware though, running without a proper brickwall limiter leaves your sub drivers at risk of blowing. But again, getting a system off the ground at the absolute minimum cost, and at the 100 to 150 watt level... I'd personally take that risk. And there's certainly people who wouldn't and would recommend you don't either.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Bill Fitzmaurice
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Re: Working on new build, need amp advice

#3 Post by Bill Fitzmaurice »

DR280 are OK, but assuming festivals means outdoors a 2:1 ratio of subs to tops is a must. I'd also use twelves in the subs, the best I could afford. Buy once, cry once.

nortonw3
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Re: Working on new build, need amp advice

#4 Post by nortonw3 »

Third, if you plan to use them primarily outdoors, you'll get more useable output with Titans.
Yes I will primarily be using them outdoors, but also indoors at after parties and the music I will be playing is deep dub so the lower the subs can fire the better. I much prefer lowness to loudness anyway. 12” definitely seems the way to go on that I’m thinking lab12 drivers now.

I definitely plan on getting a driverack down the road. They seem really useful. And glad to know I only need one amp. I only plan on running the subs in mono anyway. And I’m guessing there wouldn’t be much benefit to running the tops in stereo if it’s a small stack that are close to each other right?

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Bill Fitzmaurice
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Re: Working on new build, need amp advice

#5 Post by Bill Fitzmaurice »

You have no choice but to run subs in mono. Left/right content below 100Hz on recordings has been summed to mono since the mid 1970s. Stereo is only of benefit in the mains if the audience can hear both left and right speakers.

jimbo7
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Re: Working on new build, need amp advice

#6 Post by jimbo7 »

I agree with everything above.

I started on a kool-aid and ramen noodle budget with a bp102 t24, 12" tops and old iron amp with radio-shack quality mixer (setting voltage with a meter and putting tape at the max levels :shock:). It worked fine for house parties till I could afford to upgrade a piece at a time. Looking back at all the gear I've bought and sold over the years, I should've just got the premium drivers and gear to begin with. But sometimes you get that itch and have to scratch it any way possible.

So my advice is go with the 2x Titans vs your tops (OT's are no slouch), use premium drives, find an amp that will power them, get a Driverack or DCX, power conditioner (Bill, consensus...we still doing that?), and a spool of speaker cable and speakon connectors
edit: and a balanced mixer
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

nortonw3
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Re: Working on new build, need amp advice

#7 Post by nortonw3 »

so heres what im thinking to drive the subs at least. if I run 4 tuba45's with lab 12 drivers, I could power them with the Behringer nx3000d (2 subs per channel in parallel) the amp is 2 ohm stable so if two of the subs are daisy chained on each channel that would bring the impedance down to 3ohm on each channel right? the nx3000d also has dsp already built in and its not too expensive.

Bruce Weldy
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Re: Working on new build, need amp advice

#8 Post by Bruce Weldy »

nortonw3 wrote: Tue Mar 08, 2022 6:55 pm so heres what im thinking to drive the subs at least. if I run 4 tuba45's with lab 12 drivers, I could power them with the Behringer nx3000d (2 subs per channel in parallel) the amp is 2 ohm stable so if two of the subs are daisy chained on each channel that would bring the impedance down to 3ohm on each channel right? the nx3000d also has dsp already built in and its not too expensive.
Best I can tell, that amp doesn't have the limiting you need with folded horn subs. You'll need the driverack anyway, so buy the cheaper amps without DSP - let the driverack handle that.

And since Behringer fudges their power ratings - I think you'll be hitting the limit of that amp with the subs. That amp is fine for tops, but you need something beefier for subs.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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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Seth
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Re: Working on new build, need amp advice

#9 Post by Seth »

My recommendation to forego the use of a Driverack was strictly limited to the scenario in which the T45's are loaded with BP102's or Delta 12LFA's and amplifier output was 35v (150w@8Ω) or less. If you're considering stepping up to drivers and amps that can run more than that, I wouldn't run without it. Low power and inexpensive drivers? Sure. High power and drivers that cost twice as much, or more... without a true Brickwall Limiter? No thanks.

LAB12 voltage limit in the T45 is 50v. Off the top of my head and without rummaging through old threads, I wanna say the NU3000 and NU4-6000 put out 49 volts under load as measured by Corona Operator back in the day. Somewhere around there. It would only be an assumption that the newer "NX" series amps would likely be the same. If budget allows, it would be money well spent to look into Crown, QSC, or even Peavy IPR² amps. However, if the budget is too thin, the NX3000 would likely be enough to get started with. Any deficit in performance would be fairly minimal. But, like Bruce said, don't waste your money on DSP in the amps at that point. Save it for an outboard processor with true Brickwall limiting.
nortonw3 wrote: Tue Mar 08, 2022 4:18 pm Yes I will primarily be using them outdoors, but also indoors at after parties and the music I will be playing is deep dub so the lower the subs can fire the better. I much prefer lowness to loudness anyway.
.
I have a good portion of music in my library with content as low as 16Hz. I completely agree, I also prefer more extension over more volume. That said, if the system is primarily used indoors and outdoor usage is rare and low priority, I'd say go ahead and stick with the Tuba's. If it's primarily intended to be used outdoors with occasional indoor use, no matter the genre, I'd go Titan all the way. Without the benefit of boundary loading, the little bit of additional extension a Tuba offers over a Titan is of little to no use unless you plan to build a lot of cabs. With my T39 high passed at 45Hz on a 24dB/octave slope, 30-35Hz content is still present at a decent and audible level. So, it's not like the lower content is completely missing. Below 30 is not real apparent though, it does occur as missing. It's not a detrimental decision. Either will suit pretty well in either situation. You'll likely be happy with either.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

ACUA
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Location: Tucson Arizona

Re: Working on new build, need amp advice

#10 Post by ACUA »

If I could start over I would build titan48 subs instead of tuba45. Nothing wrong with my tuba45s but that extra 5hz on the low end does not pay off for me to justify them. The additional 3in of cab length does not offset use of the titan48 in My situation and the additional output and ability to v-plate would be better.

I support everyone’s advice so far great content. I run crown XLS series amps and have been happy with them. Most were bought used off guitar center.
Advanced Concepts Underground Audio

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