Measuring voltage and setting gains?
06-09-2004, 11:33 PM
#11
500 Watt CAFz'r
Join Date: Jan 2003
Posts: 575
http://www.jlaudio.com/tutorials/Inp...nsitivity.html
Same thing can be applied to all amplifiers ...
Power = Voltage*Voltage/Resistance
If you're using bass boost, use a tone at the center frequency of the boost (For example, if you have boost set to +6 dB @ 45 Hz, use a 45 Hz test tone)
[ June 10, 2004, 12:34 AM: Message edited by: Jmac ]
Same thing can be applied to all amplifiers ...
Power = Voltage*Voltage/Resistance
If you're using bass boost, use a tone at the center frequency of the boost (For example, if you have boost set to +6 dB @ 45 Hz, use a 45 Hz test tone)
[ June 10, 2004, 12:34 AM: Message edited by: Jmac ]
03-17-2005, 06:21 PM
#12
1000 Watt CAFz'r
Join Date: Jun 2002
Posts: 1,242
Originally posted by DWVW:
Get a test disc with 1K tones at 0, -5, -10 dB reference levels. For pure SQ use 0 or -5, for everyday systems use -10 dB.
Get a test disc with 1K tones at 0, -5, -10 dB reference levels. For pure SQ use 0 or -5, for everyday systems use -10 dB.
Honest question as I would really like to know [img]smile.gif[/img]
and you can download some testones here:
www.hometheaterhifi.com/down
03-17-2005, 07:53 PM
#13
Guest
Posts: n/a
Only older home audio tube amps got mad playing without an load... You will be fine..
0dB means - you amps should clip at the same time as your head unit, if music is recorded on the disc at full volume. The problem is, most discs aren't recorded at full volume, so you can't get the maximum out of your system. The relative levels (-3,-5, -6, -9, -10) descibe the amplitude of the signal relative to 0dB. I suggest -5 or -6 for most folks...
As a side note, I have a compilation of system setup cds available on my website - www.ofsoundmind.com
0dB means - you amps should clip at the same time as your head unit, if music is recorded on the disc at full volume. The problem is, most discs aren't recorded at full volume, so you can't get the maximum out of your system. The relative levels (-3,-5, -6, -9, -10) descibe the amplitude of the signal relative to 0dB. I suggest -5 or -6 for most folks...
As a side note, I have a compilation of system setup cds available on my website - www.ofsoundmind.com
03-18-2005, 07:54 PM
#15
Guest
Posts: n/a
The amp would have clipped 5dB earlier..
The trick to this setup is, you need to decide which amp in your system will clip first, this is the one that is set the most sensitive. That's why you need a disc with multiple levels and frequencies...
[ March 18, 2005, 08:56 PM: Message edited by: Dave_MacKinnon ]
The trick to this setup is, you need to decide which amp in your system will clip first, this is the one that is set the most sensitive. That's why you need a disc with multiple levels and frequencies...
[ March 18, 2005, 08:56 PM: Message edited by: Dave_MacKinnon ]
03-19-2005, 01:09 AM
#16
The traditional way to set gains is with pink noise... do a little reading and you might understand why... [img]graemlins/thumb.gif[/img] [img]graemlins/freak.gif[/img]
Best rule of thumb you can take is to have the amps clip at the same relative level and preferably well before the head..... set gains, points, and EQ for proper response from there...
[ March 19, 2005, 08:30 AM: Message edited by: Haunz ]
Best rule of thumb you can take is to have the amps clip at the same relative level and preferably well before the head..... set gains, points, and EQ for proper response from there...
[ March 19, 2005, 08:30 AM: Message edited by: Haunz ]
03-19-2005, 10:34 AM
#17
1000 Watt CAFz'r
Join Date: Jun 2002
Posts: 1,242
SO then the amp will clip but it takes a signal that is higher than what you should be putting out of the deck...and therefore you should not be driving the amp into clipping?
Haunz care to elaborate on the method using pink noise?
I have always set gains by ear using music. I am attempting to compile other methods in order to discuss in an article the different methods.
Thanks again for the input.
Haunz care to elaborate on the method using pink noise?
I have always set gains by ear using music. I am attempting to compile other methods in order to discuss in an article the different methods.
Thanks again for the input.
03-19-2005, 12:09 PM
#18
? I mean the amps should clip first so you are sure you always have clean signal from your source...
^ that isnt necassarily a bad way to set gains man.. really.. we listen to music and not 1khz test tones right ???
Pink noise has a similar 'program' to music... its constant and easily repeatable... thats why its often used to set levels (infact I think thats what its intended purpose is in the first place).... dosent make much sence to use any one tone as different amps may play different freq ranges and actual impedance can make a big difference on where the gains should be set....
ie.. I dont think you will fair very well setting gains on a class D sub amp using 1khz tones.. you may also run into problems if an amp sees say, 8ohms at 1khz but 3.2ohms DCR when you first power up....
^ that isnt necassarily a bad way to set gains man.. really.. we listen to music and not 1khz test tones right ???
Pink noise has a similar 'program' to music... its constant and easily repeatable... thats why its often used to set levels (infact I think thats what its intended purpose is in the first place).... dosent make much sence to use any one tone as different amps may play different freq ranges and actual impedance can make a big difference on where the gains should be set....
ie.. I dont think you will fair very well setting gains on a class D sub amp using 1khz tones.. you may also run into problems if an amp sees say, 8ohms at 1khz but 3.2ohms DCR when you first power up....
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