Subwoofer Question

[UMT]

I'm getting and reading conflicting opinions:

 

I'm running a subwoofer @ 4ohms/300 Watt RMS/1000 Watt Peak...

 

I'm hearing/reading that I should put no more than 1000 watts of power to them?

 

Right? Wrong? More power or slightly less?

[abzurd]

1,000W would be VERY foolish. These are general guidelines:

 

RMS power (300W) If you're a novice user and have no speaker management (limiting, low pass filter). The high pass filter (HPF), is nice because it can filter out frequencies your subs can't product anyway, like 40 Hz and lower. Even some basic EQ's have this feature. The limiter will limit the signal strenght so an "oops" won't get through to the amps and on to the speakers. The cheapest limiter I know of is in the Samson S3 crossover. It doesn't sound pretty when it kicks in, but I can attest that it does work. You'll need a crossover anyway so if you don't have one it's one to look into.

 

1.5 RMS power (450W) If you know what you're doing and have an HPF on your amp or EQ. I'd not go much past this if running sound from stage simply because you can't react to any sudden issues quickly enough.

 

2x RMS power (600W) If you're an expert with proper limiting, HPF.

[Unalaska]

I think what abzurd meant to say was HPF (high pass filter, lets the highs pass on and cuts lows). Unfortunately with specs it's best to know what make/model since that gives me a better idea of what to believe. 1000w Seismic audio is different than 1000w of JBL SRX.

[abzurd]

yep - sorry - corrected

 

Something else to understand is that it takes a lot more watts to make even a little more sound. It doesn't work like 800w is twice as loud as 400w. Some basics:

 

- Every 10 dB is a doubling of volume. So 100 dB is 2X a loud as 90 dB.

 

- In theory it takes 10X the power to double the volume

 

- In theory it takes 2X the power for a 3 dB increase, which is perceivable, not not a huge difference.

 

- In theory it takes 4X the power for a 6 dB increase, this is a pretty noticeable difference.

 

So the short story is that putting an obscene amount of power into a speaker isn't really going to make much of a difference.

[Coaster]

by all means give it more than 1000 watts.

 

 

and then buy a new one and give it around 300 watts.:wave:

 

300 watts at 4 ohms? are you sure?

[agedhorse]

Coaster, what speaker is that from? Certainly not (real) pro audio of a recent vintage? Looks to me like either an Asian lookalike or a guitar spealer of some sort. The reason I say this is that the bobbin looks like impregnated Kraft (a paper based material) which is VERY unusual.

[Coaster]

i have no idea. i found it on google

[Coaster]

heres some pics of someone we all know of that had a nice pleasant sub/power ratio

 

 

of course it could not have been to much power; oh no.

 

 

only 1800 watts per box, maybe underpowered? :D

 

nah. give'm hell.

[Unalaska]

I just keep thinking of the space heater in my garage. Tiny wires, lots of power thru it...

[UMT]

Thanks, guys. I've been around playing forever but after going thru 3 'sound companies' in the last 3 years, I finally decided I could do just as well by myself. It's working out fine but I had to bring myself up to speed on the latest in Live Sound. Just playing locally these days for about 200 +/- size rooms, most are new and all steel, brick, tile and hard surfaced rooms so having a HUGE PA hasn't been necessary but I did recently decide to add subs mostly for bass/drums to get that extra little kick. Primarily using Sonic speakers which we've had great luck with for years. (Sonic's are made in our home state) I'm 'out front' for the first half of every set so I get a good sound going and 'set it and forget it' with only minor tweeks.

 

It's funny, back in the day, we used to run amps and speakers not really knowing or paying any attention to Power Ratings/RMS/Peak Power/Ohms, etc.. and never blew a speaker. Hell, I was 25 and had been playing for 12 years when monitors first came out. I once played in a 'heavy metal' act and we had a tri-amped PA system at the time with one of the latest power amps from Gallian Kruger (sp?). Bought it because they were considered 'hot' at the time. Blew that sucker up every single time we played out. The music store would always give us a Peavey power amp while it was being repaired. Back then, Peavey was considered 'cheap, assed junk.' But it always worked, never failed. We finally made a deal with the store to swap the GK for the Peavey.

 

So, just a 'geezer' and doing my homework beforehand and I know this is the place for 'sound' advice. (Pun intended. Ha) Any and all advice appreciated.

[Coaster]

"back in the day" most amps had a conservative amount of power. today its getting harder to find amps with less than 300 watts at 8 ohms.

[StratGuy22]

Ah the good old CS800

 

Built like a tank!!

 

 

As heavy as a tank!!!

 

 

[Audioeast]

 

"back in the day" most amps had a conservative amount of power. today its getting harder to find amps with less than 300 watts at 8 ohms.

 

 

I think that thats true but its also true that back then they were realistic about an amps output specs and these days its the marketing side that dictates its wattage... "i know its only 150w but if we put a paperclip across the banana jacks thats easily 1200w... let go with that"

[agedhorse]

Most of the power amps we see here, even the budget amps by the major manufacturers (Peavey, Crest, Crown, QSC, etc.) do deliver their rated RMS power without any real games. Part of the problem is that speaker manyfacturers have become more optimistic about the power handling and forget that they consider optimum conditions only. That's not very real world and can result in a speaker that needs to be derated by 50% for the average user.

[UMT]

That's IT! (Peavey CS800) Or it was at least something very similiar, ie: whatever they were putting out in 1976. Looked exactly the same but I'm not sure if it's the same product made today. You would think they would have done SOME improvements since 1975 but what the hell do I know? Ha.

[UMT]

First of all, I'm glad I asked the question and Thanks to everyone who replied. I'm up to speed on using the right amount of power, etc.. for the speakers...

 

Back to the subject at hand: I'm using a EQ, know how to 'ring out a room', am very careful to monitor signal inputs/outputs so no excessive overdriving, have a electronic crossover to use for the subs, use IEM's so have no real problems with feedback but after reading all the comments regarding my initial question, I'm thinking of picking up a compressor/limiter.. I'm aware that I should have one anyway because of the IEM's but, as I said, I really don't have any issues with feedback. Classic rock band and don't really have to push anything to get the sound we want. Always have plenty of headroom without worrying about feedback.

 

Ok, so if I pick up a compressor/limiter,,, should I have a separate one just for Sub use? I'm looking at a 2 channel and running everything thru it stereo or is it best to use one channel for the mains and the other for the sub signal? Or do I need more channels?

 

Your thoughts are always appreciated!

 

Thanks,

UMT

[agedhorse]

You already have a very effective limiter built into your amp, called "DDT", and it should not be disengaged. The CS-800 will deliver about 350-400 watts RMS into 4 ohms, so with DDT engaged is an ideal match to your subs IMO. (Not knowing exactly what they are, some assumptions have been made)

 

On your crossover, it would be helpful to engage the high pass filter and it's frequency should be set as close to the speaker manufacturer's recommendation as possible.