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Sound Reinforcement  Forums for Live Sound Professionals  Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: chris fletchall on September 09, 2011, 12:17:47 am

Hello everybody. It's been a long time since I have visited the halls around here.
Well it's that time of year to start fixing and replacing broken and worn out parts.
What I have is some old Peavey hdh 3 subs that are in need of new drivers.
The current drivers are older peavey 18018 bw rated at 500w
From what I understand the newer 18018 bw are rated at 700w.
So for question one.
Since there are two in each cabinet, does this mean I can run up to 1400 watts to that cabinet ? Drivers are wired parallel in the cab.
Now to the second part.
Im currently running one carvin dcm 2000 for every two peavey subs in stereo.
The carvin is rated at 700w 4ohm stereo.
The amp is also rated at 2000w 4 ohm bridge
Would it be a better idea to get 4ohm speakers to make each cabinets total impedance 8ohm in (with proper wiring) then daisy chaining two cabs together to get a 4ohm load on the amp , and 1000 watts to each speaker?
It's been a real long time since I played with ohms law and series parallel wiring. Looks like I might have to re study on this.
Thanks for any and all input.

Well it's that time of year to start fixing and replacing broken and worn out parts.
What I have is some old Peavey hdh 3 subs that are in need of new drivers.
The current drivers are older peavey 18018 bw rated at 500w
From what I understand the newer 18018 bw are rated at 700w.
So for question one.
Since there are two in each cabinet, does this mean I can run up to 1400 watts to that cabinet ? Drivers are wired parallel in the cab.
Now to the second part.
Im currently running one carvin dcm 2000 for every two peavey subs in stereo.
The carvin is rated at 700w 4ohm stereo.
The amp is also rated at 2000w 4 ohm bridge
Would it be a better idea to get 4ohm speakers to make each cabinets total impedance 8ohm in (with proper wiring) then daisy chaining two cabs together to get a 4ohm load on the amp , and 1000 watts to each speaker?
It's been a real long time since I played with ohms law and series parallel wiring. Looks like I might have to re study on this.
Of course just because the drivers are rated at X Watts does not necessarily mean that will be the rating of the assembly of driver and enclosure but ignoring that...
One thing to consider is that the 1801 LT BW in either 4 or 8 Ohm versions is rated at 700W but that is a program rather than continuous rating. The continuous rating is 350W.
In stereo mode your amp is rated at 425W/ch into 8 Ohms, 700W/ch into 4 Ohms and 1,000W/ch into 2 Ohms. It is also rated in bridge mode at 1,400W into 8 Ohms and 2,000W into 4 Ohms. You have two subs, and thus four identical drivers, per amplifier, so each driver would see either one half the rated power of a stereo channel or one quarter the rated bridge mode power.
If you used the subs normally, that is two 8 Ohm drivers in parallel in each box on each channel of an amp, that would apparently be 350W per driver. If your goal is to still drive two subs with one amp then if you played with the drivers and wiring you might get up to 500W per driver with your current amps but that would require the amps to work harder (keeping in mind that the minimum impedance of each driver is likely below the nominal impedance). Not to mention that going from 350W to 500W would be a theoretical 1.55dB increase, which may not even be noticeable.

+1 to Brad's post. You'll have less distortion and lower the chance of failure as long as you do not drive the amp into clipping. At some point consider replacing the amp, as it's really not a great choice for a sub amp.

Hello everybody. It's been a long time since I have visited the halls around here.
Well it's that time of year to start fixing and replacing broken and worn out parts.
What I have is some old Peavey hdh 3 subs that are in need of new drivers.
The current drivers are older peavey 18018 bw rated at 500w
From what I understand the newer 18018 bw are rated at 700w.
So for question one.
Since there are two in each cabinet, does this mean I can run up to 1400 watts to that cabinet ? Drivers are wired parallel in the cab.
Now to the second part.
Im currently running one carvin dcm 2000 for every two peavey subs in stereo.
The carvin is rated at 700w 4ohm stereo.
The amp is also rated at 2000w 4 ohm bridge
Would it be a better idea to get 4ohm speakers to make each cabinets total impedance 8ohm in (with proper wiring) then daisy chaining two cabs together to get a 4ohm load on the amp , and 1000 watts to each speaker?
It's been a real long time since I played with ohms law and series parallel wiring. Looks like I might have to re study on this.
Thanks for any and all input.
I would get hold of Peavey and see if the new BWX series speakers would work in your boxes. They have 3 in the series and they are designed for 3 different size boxes. One may have the right numbers for your box volume/tunings.
I put some BXW CUs in some 3.5 cubic foot boxes tuned to 40hz with great results. They are 500 watts rms, 1000 watt program and I have available an 800 watt rms amp per speaker. (24db lowcut at 40hz)
With the BWX line you would have 1000 watts RMS , 2000 watts Program power handling per box. (Properly low cut and with the right driver for the box) I like those subs. Good output for what they are. They may have a low freq. limit of 45hz.
Douglas R. Allen
EDIT: Box tuning is 40hz. Low freq. limit is 45. If you don't already you'll want a low cut around those freq. Consult peavey on the BWX line.
http://www.peavey.com/assets/literature/manuals/HDH3.pdf

+1 to Brad's post. You'll have less distortion and lower the chance of failure as long as you do not drive the amp into clipping. At some point consider replacing the amp, as it's really not a great choice for a sub amp.
What makes you think it isn't a great sub amp? Give me details, I wanna know!
How many times have you used them? Have they ever failed on you or do you just not like certain brand names out there?

No, Ryan, I have no brand bias (I even own an American Audio amp), but the Carvin amp mentioned is not in the power range that I would consider a rocksteady sub amp, such as a QSC RMX5050, a Crown Xti 6000, or even a PV CS4000. Of course, as long as it gets loud enough (and doesn't break down) any amp is a good amp.

Since there are two in each cabinet, does this mean I can run up to 1400 watts to that cabinet ?
A: Yes
Now to the The amp is also rated at 2000w 4 ohm bridge
A: Cool. Get another amp and run 1 cabinet off each amp.
Would it be a better idea to get 4ohm speakers to make each cabinets total impedance 8ohm in
A: No. Pain in the arse. boxes would have to be wired in series (or be a 2 ohm load) which means if 1 spkr. blows they BOTH quit working. Also 2 ohm nominal loads can cause amps to overheat and/or blow! Also they would then be oddball boxes you'd have to warn everyone not to hook up as usual and they wouldn't "play nice" (mix & match well) with other boxes. Harder to readily find parts for, etc.
Thanks for any and all input.
A: You're welcome. Have a great day!,
Chuck
PS: Carvin DC 2000's are dandy little amps, just a little under powered for this application. Thus the recommendation to use them in bridge mode.
PSS: Be sure to use a subsonic filter, so you don't over excursion your cones. (I've had Peaveys yank their lead wires out!) OW$$!