| squidbait |
| I am looking at purchasing a sub amp. My question is, because of the set up in my room, it would be simple if I could use the high level in on the amp because I have speaker wire there already. Is there any downside to using the high level in? |
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| peranders |
| It is possible as long as the sub can handle it. |
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| squidbait |
| After thinking more about my question, does using the high level in, bypass the amplifier section? Or does it convert the high level signal to something the sub amp can use? Am I making any sense here? |
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| rabbitz |
| The high level signal is attenuated, mixed to mono and then is processed the same as the low level and yep goes through the amplifier section. |
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| squidbait |
Rabbitz,
Is there any quality loss, or reason I shouldn't use that route?
Also, as I don't know much about amps, I have 2 65 watt Adcom apms sitting doing nothing. They are fairly good amps. How would they compare to the 250 watt parts express sub amps? |
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| leadbelly |
| quote: | Originally posted by squidbait
I have 2 65 watt Adcom apms sitting doing nothing. They are fairly good amps. How would they compare to the 250 watt parts express sub amps? |
If you are willing to use both amps, 1 for each voice coil of a DVC sub driver, you will probably be happy with the power levels. |
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| rabbitz |
Hi squidbait
No problem using hi level in sound quality. The only thing where it would be a disadvantage would be for LFE channel on DD or DTS.
You could always try one of your amps and see how it goes but you'd need some sort of sub bass processor with a crossover so only the low frequencies are used.
I use an old Yamaha 45W amp on 1 of my setups, threw everything out except the power amp and power supply and added a sub bass processor which has has the crossover, gain control, equaliser, 20Hz filter and amp bridging ability. Enough volume without bridging (high effciency woofer of 91db though) and IMO cleaner and better controlled than a plate amp. Otherwise you'd have to build a passive crossover which ain't cheap.
I own 2 Parts Express plate amps, had 1 Jaycar and had 1 B&W and could someone tell my why are plate amp's transformers so noisy compared to a Hi Fi amp. Cost I suppose. |
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| squidbait |
Rabbitz,
I figured I would have to build a passive crossover. I didn't think it was going to be that expensive though.
Can you direct me to a project that uses a passive crossover, or a similar setup to what you have?
Thanks! |
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| rabbitz |
Can't say I seen a project with a passive crossover that low but to give you an idea for a 2nd order 12dB xo at 100Hz (should be a steeper slope for a sub):
for 4 ohms you need 12.5mH inductor & 200uF cap
for 8 ohms you need 25mH inductor & 100uf cap
These values have to be calculated for the impedance at the crossover frequency and these inductors and caps get pricey, probably about half price of a small plate amp.
The sub processor I used was a kit from Jaycar in Australia.
http://www1.jaycar.com.au/productVi...x=&SUBCATID=557
Might be something similar in the US. |
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| squidbait |
| Thanks Rabbitz. |
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| leadbelly |
| quote: | Originally posted by squidbait
I figured I would have to build a passive crossover. |
Just to get another point of view, I disagree with rabbitz. I wouldn't pursue a passive speaker level crossover for what you're trying to do. I would look first at implementing a passive line level crossover:
http://www.t-linespeakers.org/tech/...assiveHLxo.html |
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| Alcaid |
| ...or how about an active crossover? Even at low frequencies the passive komponents (R & C) are cheap. You can tap in on the power supply on your amp an regulate it down to +-15V or so. |
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| rabbitz |
| quote: | Originally posted by leadbelly
Just to get another point of view, I disagree with rabbitz. I wouldn't pursue a passive speaker level crossover for what you're trying to do. I would look first at implementing a passive line level crossover:
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I was showing squidbait the components required to show how expensive they are.
Have to agree with you leadbelly that passive speaker level is not worthwhile that's why I used the Jaycar processor which does all the work, attenuates the speaker line level, mixes to mono and provides crossover and gain control for less than the price of an inductor. |
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| leadbelly |
| quote: | Originally posted by rabbitz
Have to agree with you leadbelly that passive speaker level is not |
That makes 2 of us :)
Any jobs for process engineers like me in sunny Oztraya? It's bloody - 40 C with windchill here today :frosty: :snowman: |
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| rabbitz |
| quote: | Originally posted by leadbelly
It's bloody - 40 C with windchill here today |
I almost missed the "-" sign, -40 C, not for me, bbbrrrrrrrr, about 28 C here today. Reminds me of the one where the Canadian wakes up in bed and finds a block of ice in his bed. So he throws it in the fire and it goes bbvffff (fart noise). (For those that don't get it, was that cold that it froze his fart).
We complain about being cold in winter when it's 15 C.
Engineering jobs are getting fewer in Oz due to our declining manufacturing industries. I'm a mechanical engineer, over 25 years in the game, who hasn't worked since 1997, not complaining as unemployment (retirement) is great and gives me heaps of time for hobbies. |
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