I'm looking into sub amps to drive a pair of Stryke Audio AV12 subs. Ideally I'd like 1kw of power each into 4 ohms, but due to the cost my preference at present is for a local Altronics PA amp which puts out 450w x 2 into 4 ohms and costs $AUD 450 on special.
Altronics Amp
Has anyone had experience with Altronics amps?
Has anyone heard anything about them?
Comments, suggestions, anyone?
PDF data sheet with specs
Please note: I prefer not to get a plate amp and as I'm in Australia would prefer locals amps (unless there is an extremely good deal after shipping costs are added).
Altronics Amp
An externally hosted image should be here but it was not working when we last tested it.
Has anyone had experience with Altronics amps?
Has anyone heard anything about them?
Comments, suggestions, anyone?
PDF data sheet with specs
Please note: I prefer not to get a plate amp and as I'm in Australia would prefer locals amps (unless there is an extremely good deal after shipping costs are added).
Well I can let you know how it goes after my amp arrives for my simple vented tempest subby. But the sale might finish before it gets here.
Hmmm, good point. You were the one who alerted me to the sale and prompted me to look into it. About time I got some serious power to my subs!
The amp looks like it do the job..although you can push the strikers a tad bit more...
Most of these amps are build in china..opn the same assembly line as the lower class Crowns..qsc...crest and so on..
I bought a Crest 2600 to power my dual tempset subs ...the power rating is at 750 per side at 4 ohms....I picked it up on special for 599..canadian...
Most of these amps are build in china..opn the same assembly line as the lower class Crowns..qsc...crest and so on..
I bought a Crest 2600 to power my dual tempset subs ...the power rating is at 750 per side at 4 ohms....I picked it up on special for 599..canadian...
Jonz, yes I could push my AV12s a LOT more. John @ Stryke said they actually have a thermal rating of more like 700w. I have modelled them in many different programs - WinISD pro, Subwoofer simulator and a number of Excel based programs. IIRC it can take over 1kw to reach xmax in some vented box designs. It turns out that this kind of power is just too expensive. If cos was no object I'd get some insanely powerful amp with 2kW which could reach xmax in any box without ever coming close to clipping. I doubt the thermal power rating would ever be a problem as bass is very dynamic and the continuous level would never be very high for long. I have heard from PA guys that many blow up the Labsub with crazy powerful amps and the drivers always fail mechanically rather than melting - I have seen pics of shredded surrounds, etc.
Still, coming back down to earth, more powerful amps just seem to be far more expensive. Further I don't think I'm going to like the sound of this driver pushed to its limits, something which is more appropriate for XBL2 drivers. This amp is AU $450. For $800 I can get a Behringer with 650w but that's only about 1.5 db more - barely audible. ie. who can tell the difference between 110 and 111.5 db? Or I could bridge the Behringer and get 2 x 2.4kw at a cost of $1600 - but although that gets me quite a lot more potential output, I could probably only use about 4db of it, still not that significant. But now I'm getting to a price point where I'd be better getting a second Biema amp and pair of AV12 drivers which doesn't cost much more than AU $1000 and operating them more within their limts. But at this point I'd be spending more on drivers than the cost of a Tumult!
Ok, I'll stop thinking out loud now ...
Still, coming back down to earth, more powerful amps just seem to be far more expensive. Further I don't think I'm going to like the sound of this driver pushed to its limits, something which is more appropriate for XBL2 drivers. This amp is AU $450. For $800 I can get a Behringer with 650w but that's only about 1.5 db more - barely audible. ie. who can tell the difference between 110 and 111.5 db? Or I could bridge the Behringer and get 2 x 2.4kw at a cost of $1600 - but although that gets me quite a lot more potential output, I could probably only use about 4db of it, still not that significant. But now I'm getting to a price point where I'd be better getting a second Biema amp and pair of AV12 drivers which doesn't cost much more than AU $1000 and operating them more within their limts. But at this point I'd be spending more on drivers than the cost of a Tumult!
Ok, I'll stop thinking out loud now ...
A thought: if you double the number of drivers, you double the efficiency. That may be a more economical way to buy more power than, uh, buying more power. It also reduces power compression by sharing the power over two voice coils, which could yield a little more loudness.
The Biema amp has 450w into 4 ohms or 300w into 8 ohms. Adding 2 more drivers increases sensitivity due to doubling SD, but the available power is now less - 1.5dB. The gain in output is therefore only 1.5db. The drivers will be operating with less distortion, however. This would be the real advantage. Quite possibly a better idea than spending an inordinate amount on excessive power. I suspect that in the case of a sub, the distortion and non linearities that result from pushing drivers hard are more than those caused by pushing an amp too hard. If I'm not mistaken, clipping sub amps is much less of a problem than an amp driving fullrange speakers.
One thing I wonder about using inexpensive Chinese-made studio/PA
amplifiers to drive subwoofers is whether they can achieve their full
power reproducing a predominantly 20-60 hz signal, for example, a low-pass
filtered organ pipe with a 16 hz (or even 32 hz) fundamental.
The T.amp S-150 I suggested a few weeks ago has a couple 15 000µF 63V
power supply filter capacitors. I don't know much about such things,
but I would assume its designers were competent but cost-conscious and
chose the smallest capacitors that would provide the amplifier's rated
power for a typical full-range audio signal into a 4 ohm load.
Would the same amplifier need larger supply capacitors to reproduce a
signal whose frequency is below the supply's 50/60 hz power line refresh
rate? For example, should they be twice as large (33 000µF each) to drive
a 25 hz signal?
amplifiers to drive subwoofers is whether they can achieve their full
power reproducing a predominantly 20-60 hz signal, for example, a low-pass
filtered organ pipe with a 16 hz (or even 32 hz) fundamental.
The T.amp S-150 I suggested a few weeks ago has a couple 15 000µF 63V
power supply filter capacitors. I don't know much about such things,
but I would assume its designers were competent but cost-conscious and
chose the smallest capacitors that would provide the amplifier's rated
power for a typical full-range audio signal into a 4 ohm load.
Would the same amplifier need larger supply capacitors to reproduce a
signal whose frequency is below the supply's 50/60 hz power line refresh
rate? For example, should they be twice as large (33 000µF each) to drive
a 25 hz signal?
The response of the Biema amp is -1.5db @ 10 Hz
The rated power is 450w into 4 ohms with 0.1% THD @ 1KHz
The distortion might be a bit high at full rated power.
Can this amp produce that much power from 20 - 80 Hz? ... I hope so!
I'm not sure if it can handle that much power fullrange or at 1kHz.
Can anyone shed some light on this?
The rated power is 450w into 4 ohms with 0.1% THD @ 1KHz
The distortion might be a bit high at full rated power.
Can this amp produce that much power from 20 - 80 Hz? ... I hope so!
I'm not sure if it can handle that much power fullrange or at 1kHz.
Can anyone shed some light on this?
About low frequencies and the power supply refresh rate: if your line frequency is 50 Hz, the caps are being recharged at 100 Hz. So, for low frequencies the caps will be resupplied several times during a single cycle.
It would be comforting to see an FTC power rating for these amps (RMS watts, 20 to 20kHz, both channels driven). If those are real watts, that's a heck of a good price for a new amp. I've paid as much for used amps (Peavey & AB) with comparable power ratings (but in real RMS watts) and figured I got a fair deal.
It would be comforting to see an FTC power rating for these amps (RMS watts, 20 to 20kHz, both channels driven). If those are real watts, that's a heck of a good price for a new amp. I've paid as much for used amps (Peavey & AB) with comparable power ratings (but in real RMS watts) and figured I got a fair deal.
Thank you for your response. If the amplifier is outputting a 20 hz sine wave won't that really soak the capacitors during some of those 100 hz recharge pulses and considerably increase the capacitor ripple voltage? 😕 Or is that only a minor problem?dangus said:
Can anyone suggest budget high power amp alternatives? Something I can ship from overseas and still get better value? Suppliers? I have heard Nady have good value amps ...
Another question - how significant is noise with subs? ie SN ratio? Will it still be heard or should it not be a problem due to the lowpass filter?
Paul- S/n ratio - ofcourse,you want it as high as your source unit atleast, cdplayers are normally ~100db+ . If its slightly below this its probably still a non issue - i think 80db s/n on class A amps causes 'slight hiss'
Your chasing 3db of power and it will cost you Money wise.
-I wouldnt chase that last 3db of output,which will increase your distortion
Its not like your even going to notice,and its not more technically sound to drive a transducer RIGHT to its limit when you dont have to.
Just my opinion
Cheers!
Your chasing 3db of power and it will cost you Money wise.
-I wouldnt chase that last 3db of output,which will increase your distortion
Its not like your even going to notice,and its not more technically sound to drive a transducer RIGHT to its limit when you dont have to.
Just my opinion
Cheers!
I agree - $450 for 450w vs $800 for 650w (behringer) ... not worth the extra cost for output alone, although the performance of the Behringer seems slightly better and it can handle more current
My drivers are very power hungry, and I'm not expecting to reach xmax based on simulations. A lot of power is required to do that!
According to simulations in WinISD pro .....
A vented box of 85L Fb @ 21 Hz ...
1100w x 2 sub >>> 120 dB anechoic @ 1m
This would be peak output, not continuous as it would be pushing the thermal limits of the drivers.
But to be a bit more sane, sealed boxes with eq is more what I have in mind. A pair of them with 200w reaches 112 db @ 40 Hz and below this point a combination of eq and room gain will maintain this level down to 20 Hz. The excursion peaks at 22 Hz (19mm) but at 40 Hz it is less than 10mm, so even at high output the drivers are operating in a range for music in which they are quite linear. (xmax is 23mm) This is allowing for the extra excursion as a result of the eq applied.
Pushing a bit harder, 450w pushes the driver past xmax below ~28Hz, but above 40 Hz excursion is 14mm, not much more than half of xmax. Max SPL for music is about 116 dB. Max SPL down to 20 Hz for HT is about 112 dB and 108 dB @ 15 Hz.
I hope to be able to integrate them effectively in a direct field placement - either side of the couch. This way it models best in my room, but my main challenge will then be localisation.
Hi Paul
In my experience localisation is bought about by room modes, and/or poor bass management. As long as you are reasonably flat to 100Hz with your sub localisation shouldn't be a problem.
With regards to your sub amp situation, I would opt for an amp with a larger output purely for head room. So long as you control your output levels and ensure that the subsonic xover of the amp is in line with your drivers. Remember the high pass freq of the Behringer amps is 5Hz, although they get some good raps I have never used one myself.
Here is a good personal review of the larger unit by Tom Rosback.
Behringer EP2500 Review
BassAwdyO said:
Andy, how did you determine it wasn't accurate?
Have you found something better?
Well, perhaps winISD is fairly accurate, but the manufacture's specs were inaccurate. I was once using a pair of infinity reference 1223w's for car audio and I built a rather large ported box for them. WinISD predicted Xmax at about 600w per sub @ tuning while in reality my 200w amp pushed both subs into overexcursion. I had the box tuned to 30hz and the track It would always go beyond Xmax on was called "the woofer cooker (no joke)" I used a FFT on some computer software I had and found the lowest tone was at 29hz. I dont think 1hz below tuning is enough to make the sub achieve Xmax at that significant of a change in power. I'm pretty certian that the amp wasnt going into clipping, as I have heard that sound before and it was entirely different. It was, however, a rather large box (5+cubic feet I dont remember exactly how large) for the subs, very underdampened. I had the subs in a smaller box some time later tuned to the same frequency and I couldnt achieve Xmax even if the amp was turned to the point where clipping became audible.
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