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viziers
10-01-2007, 08:36 AM
Ok all here is where the newbness comes out in me.

So the questions is if you are using a component set of speakers and they are rated at 4ohm and you connect them to one channel on the amp would it be considered a 2ohm load because you have 2 speakers mid/tweet hooked to the crossover and then to the one channel on the amp (not bridged). Is that correct or would it still remain at a 4ohm load.



viziers

Sunfire01
10-01-2007, 08:52 AM
Remains 4 ohm.

viziers
10-01-2007, 08:54 AM
Remains 4 ohm.




Does it remain at 4ohm because of the crossover?



viziers

DejaWiz
10-01-2007, 10:18 AM
Does it remain at 4ohm because of the crossover?



viziers

That is correct. The crossover filters a certain range of frequencies to the mids and tweeters independently.

For example:
Crossovers send the mids 0-3000 Hz and the tweeters 3001+ Hz. Since the amplifier is getting a 4 ohm load from 0-3000Hz and a 4 ohm load from 3001+ Hz, the nominal load is still 4 Ohms for the entire frequency range that the amp is able to respond to. Both the mid and tweeter will get the full rms power from the amp channel they're connected to. If an amp is rated at 2x125w rms, then each mid and tweeter will be getting 125w rms each.

viziers
10-01-2007, 10:51 AM
That is correct. The crossover filters a certain range of frequencies to the mids and tweeters independently.

For example:
Crossovers send the mids 0-3000 Hz and the tweeters 3001+ Hz. Since the amplifier is getting a 4 ohm load from 0-3000Hz and a 4 ohm load from 3001+ Hz, the nominal load is still 4 Ohms for the entire frequency range that the amp is able to respond to. Both the mid and tweeter will get the full rms power from the amp channel they're connected to. If an amp is rated at 2x125w rms, then each mid and tweeter will be getting 125w rms each.



Thank you DejaWiz and everyone else for your answers it has helped out a lot!


Now all i need to do is get an Oscilloscope so i can set the gains just right, I do have a DMM but prefer the exactness of the Oscilloscope. I'm dreading the wiring as its a B7 A4 2.0T and that it has airbags ALL OVER the place including on the seats and the interior and moldings are exact fitting.

DejaWiz
10-01-2007, 01:07 PM
Thank you DejaWiz and everyone else for your answers it has helped out a lot!


Now all i need to do is get an Oscilloscope so i can set the gains just right, I do have a DMM but prefer the exactness of the Oscilloscope. I'm dreading the wiring as its a B7 A4 2.0T and that it has airbags ALL OVER the place including on the seats and the interior and moldings are exact fitting.

No problem at all.

You might want to call some local audio shops to see if they have an oscilloscope to get your HU tested. Buying one outright is usually a very costly endeavor, but they can be had at decent prices with a little searching (http://www.testequipmentdepot.com/specials/analogoscilloscopes.htm).

tRidiot
10-01-2007, 01:12 PM
If an amp is rated at 2x125w rms, then each channel with a mid and tweeter will be getting 125w

Adapted for clarity.

So the amp will continue to put out 125W per channel (L or R), which will be split between that channel's mid and tweet.

DejaWiz
10-01-2007, 01:22 PM
Adapted for clarity.

So the amp will continue to put out 125W per channel (L or R), which will be split between that channel's mid and tweet.

Be careful there.... the power itself is not split (such as half to the mids and half to the tweeters) if the mids and tweets are being sent different frequencies. An amp channel will simultaneously output 125w rms from 0-3000Hz and 3001+ Hz, so the mid and tweeter attached to that channel will be getting a full 125w rms each.

tRidiot
10-01-2007, 10:41 PM
So you think that if you simultaneously drive the mid @ 2000Hz and the tweet at 4000Hz, then the amp will be putting out 250W?

I don't think so.


Never said it would be split evenly between them, as in 75W and 75W. All depends on what's playing at the time.

DejaWiz
10-01-2007, 10:58 PM
So you think that if you simultaneously drive the mid @ 2000Hz and the tweet at 4000Hz, then the amp will be putting out 250W?

I don't think so.


Never said it would be split evenly between them, as in 75W and 75W. All depends on what's playing at the time.

I'm talking per channel. 2x150w rms. 1 mid and 1 tweeter per channel. And yes, I am aware that during music playback, an amp will almost never put out it's max rms. Probably around half of that. I was merely trying to explain it in a manner that wouldn't confuse the fellow.

viziers
10-02-2007, 09:00 AM
No problem at all.

You might want to call some local audio shops to see if they have an oscilloscope to get your HU tested. Buying one outright is usually a very costly endeavor, but they can be had at decent prices with a little searching (http://www.testequipmentdepot.com/specials/analogoscilloscopes.htm).


The oscilloscope i was looking at is this one http://www.vellemanusa.com/us/enu/product/view/?id=351263. Would this be acceptable tool with the features i would need? Ive never used one of them so im not sure what im looking for so any input would be good.


viziers

DejaWiz
10-02-2007, 11:09 AM
Yeah, that would probably work fine since max input voltage (AC peak-peak) is 200V. Have you checked out all the features in the manual (http://www.vellemanusa.com/downloads/0/manual_hps40_10-uk.pdf)?


Can anyone confirm that this particular unit would be suitable for the intended use?

viziers
10-02-2007, 11:42 AM
Yeah, that would probably work fine since max input voltage (AC peak-peak) is 200V. Have you checked out all the features in the manual (http://www.vellemanusa.com/downloads/0/manual_hps40_10-uk.pdf)?


Can anyone confirm that this particular unit would be suitable for the intended use?


I did check out the manual and if i remember correctly it will measure down to only 2ohms but measured dbl's, watts and a few other things. If someone who has experience using these please can you take a look at the manual for us and tell us your findings?


Thanks,
viziers