I need a good quality plate amp for a Q=.707 sealed enclosure. Should I use bass boost? Linkwitz transformer?
Thanks,
Andy
Thanks,
Andy
The Parts Express plate amps are quite good and come with instructions on the resistor changes to change the boost.... dB and frequency.
I'd have a look at where your F6 is and it that's low enough give the boost the flick and don't forget about room gain.
I'd have a look at where your F6 is and it that's low enough give the boost the flick and don't forget about room gain.
Thank you for the reply Rabbitz.
According to my Bassbox software, my Dayton DVC in a 2.4L sealed enclosure, using "resistively damped operation" gives me a Q=.707, Fc=34Hz & F3=34Hz. The F6 is not listed, but from the graph it looks like 27Hz. Room gain is not taken into account.
Warm regards,
Andy
According to my Bassbox software, my Dayton DVC in a 2.4L sealed enclosure, using "resistively damped operation" gives me a Q=.707, Fc=34Hz & F3=34Hz. The F6 is not listed, but from the graph it looks like 27Hz. Room gain is not taken into account.
Warm regards,
Andy
if you gave us a picture of the graph, the dimesnions of the room it will be in, and the intended application for this subwoofer, we could help you ALOT more! you may not even need boost to get a flat response own to the mid 20s!
the PE. 300-804 amp is 240 watts rms and has the better 24 db/octave low pass filter and, with a few mods done to it performs quite well. with the soft cliping circuit, you don't have to worry about all the farting from clipping amp he he.loudnclear said:
might be worth a look. good luck, crippledchocken
🙂 http://www.parts-express.com/
Hi Andy
I can't see you needing bass boost at all as with room loading it should be fine. You don't want a flat response down into the 20's in the software as it becomes a nightmare in the room and over the top. F3 at 34Hz and F6 at 27Hz for sealed looks good.
I've used the PE 300-793 amp and the 300-794 is probably better. The other one suggested looks cool as well, so there's plenty of options.
Cheers
I can't see you needing bass boost at all as with room loading it should be fine. You don't want a flat response down into the 20's in the software as it becomes a nightmare in the room and over the top. F3 at 34Hz and F6 at 27Hz for sealed looks good.
I've used the PE 300-793 amp and the 300-794 is probably better. The other one suggested looks cool as well, so there's plenty of options.
Cheers
i own a 300-804, and its awesome, but for some reason it shuts off whenever i try o drive one 4 ohm driver...this might be cause i have pretty much no current going to my room, and alot of electronic devices ontop of that, btu wouldnt the breaker go before the amp shuts off?
Id definately reccomend the 804 over the other 250 watt models, variable phase isnt worth it either cause it only works at one frequency. And once you add in all the protection circuts, and the soft clipping eature AND the better low pass, its starting to look like a great deal! Besides, if you can honestly tell 10 watts difference with your ear(at that power level) then you are my hero!
Id definately reccomend the 804 over the other 250 watt models, variable phase isnt worth it either cause it only works at one frequency. And once you add in all the protection circuts, and the soft clipping eature AND the better low pass, its starting to look like a great deal! Besides, if you can honestly tell 10 watts difference with your ear(at that power level) then you are my hero!
hi there, what kind of 4 ohm driver is it? also, when you have wall receptacles feeding from one to another and develop a loose or, coroded connection feeding from one recept. to another lots of problems can result. i recently had a bad internally coroded recept. on the same branch circuit as my pc and every time the microwave was turned on, the bad recept. would cause voltage level on pc ps to drop low enough for my dial up modem to bump off line. i replaced the bad recept. and, the thing stays online now even when microwave is turned on seems to work great now with no problems. might be worth checking out that particular branch circuit all the way back to your breaker box including, breaker conn. and neutral buss bar. good luck, crippledchickenxstephanx said:
🙂
Thanks for the great reply. I think I will stick with no boost and Q=.707. I'm up the air about those two mentioed amps.
My understanding is the PE 793/4 is made in America. Does anyone know where the 804 is made? Is one of better quality?
I'm not exactly sure which amp will integrate better with my mains (run full range) 24dB/oct low pass or 12dB/oct?
Andy
My understanding is the PE 793/4 is made in America. Does anyone know where the 804 is made? Is one of better quality?
I'm not exactly sure which amp will integrate better with my mains (run full range) 24dB/oct low pass or 12dB/oct?
Andy
loudnclear said:
I have the PE794.. my only real beef is that the 2nd order xo is sometimes not enough. But the amp is great for what it is.
Okay, I ordered an amp. I decided on the Rythmik A250SE (special edition) with the 24dB/octave low pass. It's basically a Parts Express 300-794, but with upgraded parts: Mosfets, no electrolyitcs in the signal path, 24dB/octave in lieu of 12dB/octave, and some other stuff. Looks pretty nice - I can't wait to get it and try it out.
Andy
Andy
loudnclear said:
If that's the one I think it is, it's not strictly a 24dB lowpass filter. It's two 12 dB filters in series, one of which has a center frequency that is not variable. Should work fine though.
Phase control:
Phase control, when implememnted correctly, will give you a smooth xover transition (it is not just at one frequency as someone else had mentioned). Most plate amps on the market do not have the phase control designed correctly. If you are frustrated with the adjustable phase control on amps from PE, do the following: cross-wire the speakers (that is, connect the speaker out of phase) and then read the phase control backward (that is, 180 reads 0, and 0 reads 180). This way, you will get the phase control to work (still there is an issue of adjustment resolution, etc, but at least it is correct).
24db/oct:
For those who ask 24db/oct becasue they don't use the sub output from receiver, 24db/oct and phase control are eqaully important. And I would definitely recommend the our SE amps.
Brian
Rythmik Audio
Phase control, when implememnted correctly, will give you a smooth xover transition (it is not just at one frequency as someone else had mentioned). Most plate amps on the market do not have the phase control designed correctly. If you are frustrated with the adjustable phase control on amps from PE, do the following: cross-wire the speakers (that is, connect the speaker out of phase) and then read the phase control backward (that is, 180 reads 0, and 0 reads 180). This way, you will get the phase control to work (still there is an issue of adjustment resolution, etc, but at least it is correct).
24db/oct:
For those who ask 24db/oct becasue they don't use the sub output from receiver, 24db/oct and phase control are eqaully important. And I would definitely recommend the our SE amps.
Brian
Rythmik Audio
Dave Jones said:
Dave,
You are correct. The 24db/oct is implemented with one adjustable 12db/oct and one fixed 12db/oct (it is actually an 18db/oct) attenuation. This way, we can have a toggle switch so that later when one upgrades to a HT receiver, he can just toggle the switch and the amp becomes a normal 12db/oct attenuation. Fundamentally, the purpose of 24db/oct is to attenuate the upper bass signal (anything above 100hz) and this arrangement does the trick and offer some flexibility. Plus the correctly designed phase control will make the task of integration easier.
Brian
Rythmik Audio
loudnclear said:
Both www.adireaudio.com and rythmik have good plate amps.
An alternative to consider, is to get hold of a pro amp like the Behringer EP2500 and then build, buy, or have built the xover.
With an EP 2500 you have the capability of 4500 wpc in stereo @8 ohms, 650 wpc @ 4 ohms, or bridged mono operation of 1300 watts @ 8 ohms with very low distortion.
I have seen them for sale at several pro audio dealers such as zzounds, which sells it for $299.95. As a unit built to withstand the rigors of touring, it's well built and should last for a very long time. Hell, get two, one for the sub and one to run in stereo for you main speakers.
Behringer also makes a crossover as well: http://www.zzounds.com/item--BEHCX2310. In short for about $400.00 you'd be set. Compare that to anything else in that price range for a plate amp and you won't get nearly the power.
You can find out all you need to about the Linkwitz transform at:
http://www.linkwitzlab.com/filters.htm
Good luck.
I have a subwoofer output on my receiver (and I plan on using it). Why can't I use 24db/octave instead of 12db/octave? I thought the receiver's internal filter could be turned off. I do 80% music 20% HT.
loudnclear said:
Andy,
You can still use 24db/oct setting. The important consideration is the phase relation between the front speakers and subwoofer at the xover point. An ideal solution is a 360 degree phase shift (that is what Linkwitz-Reiley filters are about). So I encourage you to experiment with both settings. The previous comment is for those who insist on minimal filtering on subs. Some refer to that as double filtering. Most subs are good only below 100hz (some are even lower) so I cannot see what harm double filtering will do. But I do think maintaining correct phase relation is a far more important consideration.
-Brian
Rythmik Audio
Thank you for your replies, Brian, and I am indeed looking foward to receiving and using the 250SE.
Regarding phasing, I usually will set the subwoofer phase by wiring the main speakers out of phase and playing some bass heavy music (and test tones) at at a low level. The phase control will be tuned where the bass sounds the least, then the mains are rewired into phase with the phase control left in the same position.
Is this your recommendation for phasing?
Thank you,
Andy
Regarding phasing, I usually will set the subwoofer phase by wiring the main speakers out of phase and playing some bass heavy music (and test tones) at at a low level. The phase control will be tuned where the bass sounds the least, then the mains are rewired into phase with the phase control left in the same position.
Is this your recommendation for phasing?
Thank you,
Andy
loudnclear said:
Andy,
Your method is very effective for those who don't have SPL meters. Normally I recommend using SPL meter measuring output at the xover point (80/100hz) with front speaker only, with subwoofer only, and then with both of them. Phase adjustment is same as delay time adjustment available on the HT receiver (that is why the bug on the phase control on PE amps or our 12db/oct amps should not bother most people). Graduately adjust the phase (or delay) control until the output is highest. Then graudately adjust the xover control untill the FR is as smooth as you like. For those who have a near-field measurement system, one can just directly measure the phase of both front speaker and subwoofer.
Brian
Rythmik Audio
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