PDA

View Full Version : How much power to feed the sub.



ballstothewall
01-24-2006, 11:25 PM
Ok, I bought an ED e8a sub for my dorm room setup. I am having a friend design me a box, hes working on a 6th order bandpass but depending on how that turns out (first time hes designed a bandpass), it might possibly just be used in a ported enclosure. I am wondering how much power I am going to need to feed this little monster. It is a dual 4ohm coils, and since nothing is 2ohm stable, 8ohm is a must. I was thinking of getting this amp for it http://www.apexjr.com/Apexsenior.htm. It puts out 250@8ohm. Would this be overkill...or is that possible :up2somet: :up2somet:.

I just would like your opinion here.

Thanks

thylantyr
01-25-2006, 12:36 AM
Don't listen to me.









more is better.

http://www.docksdelamusique.com/administrer/images/articles/docksdel_bdd1-laboitenoire/CREST/SCA-10001-B.jpg


:clap: :scared:

ballstothewall
01-25-2006, 01:17 AM
Somehow, I figured I would get that advice from you thylantyr....hehe

Thats kinda what I figured though... More IS better.

Think I'm gonna get a noise complaint in the dorms?:up2somet:

ballstothewall
01-25-2006, 01:19 AM
Thats a nice looking amp also, you gonna get one for that monster sub array of yours?

joetama
01-25-2006, 03:03 AM
For a sub it's almost always true to go with the lowest Ohms possible. Depending on your budget I would go with a beastie amp with some real output transistors that can handle to 2 ohms. But that's just my opinion.....

How much I love Pro-8001 and 10001 amps they could possibly maybe just maybe be a bit over kill LOL. Oh but they will do 2 Ohms and drive EVX-180B's beautifully.....

ballstothewall
01-25-2006, 10:37 AM
For a sub it's almost always true to go with the lowest Ohms possible. Depending on your budget I would go with a beastie amp with some real output transistors that can handle to 2 ohms. But that's just my opinion.....


Could you provide some links for me??

joetama
01-25-2006, 04:31 PM
How much money are you looking to spend? That's the important part..

ballstothewall
01-25-2006, 05:43 PM
I would like to spend as little as possible, under 250 prob. Wow, I'm gonna spend more on the fricking amp then everything else combined....

ngsm13
01-25-2006, 06:33 PM
Dude. Those eD8a's will take all types of power. I had around 700rms on mine when I had it.

I'd look into around 300-400rms range @8ohms.

NG

thylantyr
01-25-2006, 07:51 PM
While this doesn't fit your budget, I always like to over-engineer the amplifier
needs for a design... because you can reuse the amp in the future if you have
bigger idea. for example, spend $250 on a plate amp with a limited active crossover
for sub or do you get a beefy proamp on the used market for $400
{being patient for the snag}.... You can get ~2kw worth of proamp for this price.
That amp can be used in 2 channel or bridged mode, but keep in mind the impedance
rating on the amp. It's a flexible choice, use it for 2ch stereo, bridge
it for subs, need more power, it has it. It's a keeper for many projects. Later,
buy a seperate digital crossover with tons of horsepower for a few bills to give
more options in the future. Buy once, keep it. This method drains the wallet,
but if you keep buying more stuff by doing upgrades over the next few years,
you spend more money. It's ok to be poor as long as you have your toys :)

ballstothewall
01-25-2006, 10:09 PM
Ok, a proamp sounds good, but I have a question or two since I don't know a whole lot. Will I have to buy a seperate crossover to start with or do the amps have one built in?

Receiver 70 bucks
Cabinets and drivers 100 bucks
Sub 76 bucks
Sub cabinet 20 bucks
Amp 450 bucks

Possible noise complaints.... Priceless

Wow, around 275 bucks for everything else and almost double that for the amp, I hope I can buy one before school is out.

Does anyone have a good link to a readup on proamps for me so I can learn some stuff, I couldn't find a good one on the interent anywhere, but I may not have been looking in the right spot.

Thanks

ballstothewall
01-25-2006, 10:13 PM
Would it be to "ghetto" to do a computer power supply mod and run the ed 8 off a car audio amp that puts out upper 300's watts rms till I get money for the proamp?? Or is that just a stupid idea?

thylantyr
01-26-2006, 12:06 AM
I think the best bang for buck proamp is QSC RMX.

http://www.qscaudio.com/

You see them on ebay all the time. I used the 2450 for months running
the midranges in the line array, works nice as is affordable.

For less money, there is Behringer EP1500 and EP2500, QSC RMX clones
but with smaller transformer so 2 ohm operation will probably struggle. /guess

But the price is $300 for EP2500, I saw a few on ebay that sold for $270.

Crown XLS is very popular on the AVS forum but they don't really abuse their
audio systems or have difficult loads to drive, but they like it alot. $250
for XLS402. But, many people do complain because it has dual fans and it's
not variable speed like RMX so there is alot of fan noise. People have modded
the amp; a. add resistor to reduce fan speed b. replaced the fans with quiet ones.
c. cut the fan wires and run it fanless

For woofers I wouldn't do that. I doubt if I ever would use an XLS because
I saw internal pics.

http://home.pacbell.net/lordpk/proamp/

Heatsinking is weak. Also for reference there is Samson pics, EP pics

and PLX / RMX internal pics here;
http://home.pacbell.net/lordpk/qsc/

Notice the EP vs. RMX pics, looks the same, EP has smaller tranny.

PLX is a higher price bracket, about double RMX pricing. Crown has more
expensive amps too. CE series would probably be a more competitive amp
with RMX.

Not to confuse you, but QSC just released PLX2, Crown announced a new
XLS that 'fixes' customer complaints. Is this good news? Perhaps, you know
people will get the itch to upgrade and they will start selling off their PLX's,
old XLS's, and what not to get the latest and greatest. Keep an eye out
on ebay.

I see some EP2500 for $259 buy it now. I'd rather have these over XLS
because of the better heatsinking...

thylantyr
01-26-2006, 12:07 AM
Would it be to "ghetto" to do a computer power supply mod and run the ed 8 off a car audio amp that puts out upper 300's watts rms till I get money for the proamp?? Or is that just a stupid idea?

You can try it for fun but don't sink big bucks into this.

joetama
01-26-2006, 01:07 AM
It would have to be on Killer power supply. The Berhinger is good, so are the QSC, I personally dont like the Crowns (CLOWNS) but if you get one cheap and aren't going to push it too much it would (i guess) work.

ballstothewall
01-26-2006, 01:42 AM
The Behringer EP2500 looks good, I could buy one of them right now, but I better restrain myself, for now. Ok, I have some more questions. How do I get my input signal to the amp. I am running a Yamaha Receiver that is from prob early-mid 90's, I'm don't know how exactly I get my signal from it to the amp, thats what I don't know. Also, maybe you answered it and I didn't see it, but would I need a cross over right now? The receiver dosen't have one built in as far as I know, it is a 5.1, but it dosen't have a dedicated sub out as far as I can tell. It has the standard speaker out, the A & B channel L & R fronts, then it has the left and right rears, and center but no sub out. It dosent' have RCA out for the audio either (except for whats labeled VCR out)

Sorry for the noob questions

-Ryan

joetama
01-26-2006, 04:06 AM
Hmmm should have Pre-Outs, what model is your Yamaha?

ballstothewall
01-26-2006, 10:39 AM
Rx-v480

ballstothewall
01-26-2006, 05:38 PM
Off topic, but I just got my sub, and it is a beefy little sucker, 15 pounds, it looks pretty **** too.

ngsm13
01-26-2006, 05:54 PM
Off topic, but I just got my sub, and it is a beefy little sucker, 15 pounds, it looks pretty **** too.

Tis true, I loved my eD8a.

NG

thylantyr
01-26-2006, 07:03 PM
You need an AV reciever with {RCA} preouts to run any external amplification.
If not, yer hosed unless you do the ultra ghetto voltage divider network on your
amplified AV outputs {don't go there}.

If you have RCA preout, buy a RCA to XLR cable.

RCA male on one end, XLR male on the other end.

Or DIY a cable.

Some proamps have 1/4" plugs too, maybe a terminal post that you can
tap into also. I'm too lazy to look a the specs.

JimJ
01-26-2006, 07:04 PM
I've had good luck running plate amps off of high level inputs before, if for no other reason because I've never owned a receiver that actually has a dedicated subwoofer output :)

ballstothewall
01-26-2006, 08:12 PM
I'm pretty sure I'm going to get this http://www.behringer.com/EP2500/index.cfm?lang=ENG

Would it be possible to go from the "B" channel front speaker output, to a line output convert, to a RCA to XLR cable?

ballstothewall
01-28-2006, 01:22 PM
Well, guys I did it. I bought an amp. I got the behringer. I will be constructing the box next weekend. So, a couple more questions...

1. What kind of crossover do I need
2. Can i go from a Line output converter to the RCA to XLR cable so I don't have to get a new receiver
3. I don't have a third, but I might be able to think one up in a couple days.

joetama
01-28-2006, 05:53 PM
2. Can i go from a Line output converter to the RCA to XLR cable so I don't have to get a new receiver

Yes you can, but there is audio loss in the Line Output converter but if you are completely against using any pre-out (ie if you dont have one) or getting a new reciever then it's really the only way to go. The amp has 1/4 inch jacks on the back and since your not feeding it a balanced signal anyway i would just go a head and use the 1/4 inch ends.

ballstothewall
01-28-2006, 06:01 PM
Yes you can, but there is audio loss in the Line Output converter but if you are completely against using any pre-out (ie if you dont have one) or getting a new reciever then it's really the only way to go. The amp has 1/4 inch jacks on the back and since your not feeding it a balanced signal anyway i would just go a head and use the 1/4 inch ends.


Thanks.

Sorry for the noob questions...

ballstothewall
01-28-2006, 06:15 PM
Ok, more idiot questions here.

I am going to need an active crossover setup to get the freq abover 100ish hertz outa the subwoofer channel. So I was wondering if I could buy something like this http://cgi.ebay.com/ART-stereo-active-2-way-crossover-w-subwoofer-out_W0QQitemZ7384483307QQcategoryZ23790QQssPageNam eZWDVWQQrdZ1QQcmdZViewItem and just use the sub output, is that possible, or just stupid?

joetama
01-28-2006, 09:01 PM
Yea should be able to use it for just a sub. I have used ART effects before but never their cross-overs but this one looks pretty good. WIth the variable cross-over point you wil be able to customize the sound alot better than if you were to use a plug in cross-over. I would say that ART cross-over is a good choice.