More power needed for Tempests? (1 Viewer)

[David Giesbrecht]

Do you have the Tempest wired in parallel (+ to +, - to -) for a 4 ohm load?

Yup

 

[Chad Kuypers]

Brian,

Apparently I didn't explain myself clearly enough. Here is what I meant:

Wiring option #1:

Each channel run seperately to a 4 ohm subwoofer load
each woofer gets 450 watts

Wiring option #2:

Subwoofers wired together in series to a single 8 ohm load
Amplifier is bridged into 8 ohms at 900 watts


Both options are identical on paper. The subwoofers get the same amount of power either way. However, the Crown amplifier just did not like to be bridged. In theory it should perform exactly the same, but it would clip and even shut off when it was bridged. When not bridged, it performed incredibly well without any problems. That is all that I meant.

I have long since sold this amplifier.

 

[David Giesbrecht]

450W is more than enough power. You're getting caught up in analysis paralysis.

I relize that maybe I'm expecting more than what I should be, and that I'm only 17 and havn't been around long enough to be considered experienced but I do think I have a valid point and some (not pointing any fingers) just arn't willing to listen because of it.

Sorry if I came off as being rude.

 

[Ben_E]

Would leaks cause the amp to work harder than it should?

 

[David Giesbrecht]

I don't think so but I have checked and they don't appear to have any, I can't hear any hissing noises or feel any air at any joints.

Thanks anyway

 

[DanWiggins]

Hi all,

David, you have great extension and flatness - flat to below 20 Hz with a pair of sealed subs is quite an accomplishment! However, you want more...

More power isn't the route to go - you're already past the limits of what your drivers can linearly handle. You need to get a box with more output per driver, rather than more power. Try a larger vented alignment. If you like the sound you have now, try the Adire vented alignment - nice and tight, better extension, and another 4-5 dB output down deep (below 35 Hz) as compared to the sealed box.

Go with a bigger vented box and see what you think. You should have a ton of output as-is; if you desire more, your options really aren't more power (you have more than enough right now), but bigger boxes, or more subs.

Dan Wiggins
Adire Audio

 

[Brian Bunge]

I say build 2 more sealed Tempests and run the amp in 2 ohm stereo mode!

 

[David Giesbrecht]

David, you have great extension and flatness - flat to below 20 Hz with a pair of sealed subs is quite an accomplishment! However, you want more...

And the best part is I use no EQ and I get that frequency response in any listening position in the room!
The bass sounds extremly tight and smooth all the way up until the amp clips:frowning: witch was rather dissapointing for me

P.S. A 5hz test tone makes the remotes on my couch bounce

 

[David Giesbrecht]

you're already past the limits of what your drivers can linearly handle.

I know that you are probably right because you designed the drivers but I have yet to hear any distortion of any kind coming from the subs except for when the amp is clipping then I get this weird blobby sounding bass

Is it possible that the clip led's come on before the amp actually clips, maybe its warning that the amp is about to clip?

 

[Wayne Ernst]

Hmmm ... Now, where's the problem?

 

[David Giesbrecht]

Hmmm ... Now, where's the problem?

The problem is producing a single 5 hz sine wave is not the issue here. I'm talking about producing movie soundtracks which contain multiple sine waves all happening at once. Even if it only takes 170 watts to bottom out my Tempest with a pure 20 hz test tone that doesn't mean thats all you need to power it. I've fed enough power into them that my 450 watts per channel starts to clip while playing back LOTR and I'm certain that they are not bottoming out.

 

[Craig Treusdell]

I'll second Dan's suggestion.
Try making one ported box with the Adire alignment and run just the ported sub with LOTR or any other movie. At first I had 2400 watts on mine -- almost blew it out of the box. Unbridged it to 750 watts -- still pops. Could have been frequencies below the tuning frequency, but it would put out.
I don't think you will be disappoined. Especially if you port 2. Or just sell 'em and get a Tumult

 

[David Giesbrecht]

I don't think porting the box is the answer because I already have a flat frequency response that extends below 20 hz. Porting the box will only raise the efficiency in the lowest range of bass so I probably would want to keep my gain at the same level anyway. Before I bought the second Tempest it was in a vented tube tuned to 16 hz and for most things the sound didn't change when I went sealed and the vented sub did not sound any louder.

Unbridged it to 750 watts -- still pops.

I think that my power is maybe not quite the same as yours was because I tried bridging my amp so I had 700 watts per driver and I had the volume on it up until the clip lights came on and I heard no popping at all.

 

[Dan Hine]

Ok David...I need to give you an analogy that may help with your understanding of a few concepts...

Porting the box will only raise the efficiency in the lowest range of bass so I probably would want to keep my gain at the same level anyway.

Be aware that the lower you go the octaves become closer together. 20hz - 40hz is a full octave which is about where you'll gain efficiency by 3db (and lower probably to about 15hz if using a 10db downpoint). This is the same as saying that you're gaining efficiency between 10khz and 20khz or 5khz and 20khz if you use the 10db downpoint. You said that the sub started off in a ported alignment and that you can't really tell the difference. If this is true then I would change to ported subs...or at least build a test box, see if you get the same output or more (you will) and then see if your clip lights go on (probably not)...be sure to play them at the same level using an SPL meter so you don't get fooled into turning them up until the clip lights come on...kind of defeats the purpose.

Above all else, have fun!

- Dan Hine

 

[Pete Mazz]

What is feeding the QSC? LFE out from reciever? What is the sub level output set at? It's possible your recievers output is actually clipping if set too high.

Pete

 

[Brian Bunge]

Pete,

That's kinda what I was thinking. Especially using something like LOTR, which has quite a bit of subsonic info. on the disc. If the receiver's running hot anyway and then you mate it with a disc that's recorded hot then you get...superhot!

 

[Brian Tatnall]

I agree with Dan Hine completely. Here is another example that may help.

http://www.eatel.net/~amptech/elecdisc/frequncy.htm

One of the examples shows multiple frequencies and more specfically gives the example of two sine waves like you are suggesting:



Remember that your speaker is only playing one frequency at a time really. It combines the different since waves into one combination wave looking like this:



This is what your amp and speaker actually see. It takes the brain to divide up the wave and recognize the two sine waves being played at the same time.

When looking at the combined wave in terms of power it just takes the amount of power for the single combined wave.

Hopes this helps some. Maybe someone can add even more detail.

 

[David Giesbrecht]

Sorry guys, I feel like a jerk. But I guess you never get an answer until you pose the question right. There is still something I'm not sure about though, I know 450 watts should be more than enough power for them and this makes sense now but I am sure I am not bottoming the subs when I've clipped the amp because if I was I would be able to hear some distortion or popping right?

What is feeding the QSC? LFE out from reciever? What is the sub level output set at? It's possible your recievers output is actually clipping if set too high.

Thats a good point I'll try setting the sub out level on the receiver a little lower and see what happens. I have it set at 0 db now I'll try it at -10.

Thank you for the good explination Dan and Brian!

 

[Dan Hine]

I am sure I am not bottoming the subs when I've clipped the amp because if I was I would be able to hear some distortion or popping right?

More than likely, yes. You would know if you had a problem. Are the clip lights just flickering a little bit or are the red lights staying on constantly? I really wouldn't worry about a flicker here or there. But if you've got two red eyes staring at you then it's time to adjust something.

- Dan Hine

 

[David Giesbrecht]

It is more of just a flicker here and there actually, I just expected 900 watts to be more than enough power to drive them way harder than I'd need to (it doesn't seem to posses much more power than the 200 watt Technics amp it replaced) :frowning: I am going to try what Pete had suggested, I was thinking before that might be the problem because even when driving it to clipping for long periods of time the amp is still cold and normally in my experiance when driving an amp that hard they get real hot real fast.
But can't do that now it's late (2:52 a.m.) and my parents are asleep. :frowning: but I will post the results tommorrow.

Sorry for draging this silly topic on forever.:b