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If Craig is going to call this place Tweak City, I'm going to ask a Tweaking question: I’d like to buy or build a circuit to connect a speaker-level signal to an unbalanced audio-level in. Anyone got any leads? Or could you please give me criticism or other thoughts on the following?
Cause I want to use this circuit to connect back to Room EQ Wizard (REW) (to use it as a speaker-level signal spectrum analyzer), I tried to ask on the REW forum, but I got defeated by those thinking I didn’t know I wanted and trying to help with the problem they thought I had instead. Since there’s nobody here but us chickens (and a few pimps :)), I’m not afraid to look like a total fool – give it to me straight!
Is all I need a Voltage Divider circuit with the ability to handle enough power? To my poor lil’ mind, based on the 200 Watts into 8 ohms an amp would put out 40V; and if I do the calc with 4 ohms I get 28V. Anyway, what with normal audio levels vs. the power required, and a good margin of safety (e.g., not allowing a teenage boy - including my inner teenage boy - to take over any volume controls), my guess is that 1/25 Voltage Divider would give me a nice input range to the computer sound card for this analysis.
I’d think I could use the following 10W resistors safely: http://www.radioshack.com/product/in...ductId=2062292
They are 50 ohm, there’s also 10 and 1 ohm 10W models. Put two of the 50s in parallel with a 1W below the outputs. One of the 50s with two 1’s in series below would be half the current – Might that be better?
Or is there a problem with that much resistance total, and I should try to mimic an actual speaker impedance? Both of these give me a 1/20 voltage division: a 10 ohm above and two 1’s in parallel below (10.5 ohm ckt), or even go to two 10s in parallel and four 1’s in parallel below (5.25 Ohm)?
Thanks in advance!
And for those who aren’t totally bored yet, this is a post with an Appendix! (it’s not important to the original question, but perhaps of interest or worthy of separate discussion): What I want to do is to look at the electrical signal to be able to measure and characterize the noise in my signal chain and try to diagnose if the majority of noise is coming from an amp, the preamp (or AVR, etc), earlier in the chain, or from power, or from cable interactions, RF interference, etc. And do this without having to account for the speaker, room (including ambient noise), or microphone (including repeatability of setup – location and orientation).
Cause I want to use this circuit to connect back to Room EQ Wizard (REW) (to use it as a speaker-level signal spectrum analyzer), I tried to ask on the REW forum, but I got defeated by those thinking I didn’t know I wanted and trying to help with the problem they thought I had instead. Since there’s nobody here but us chickens (and a few pimps :)), I’m not afraid to look like a total fool – give it to me straight!
Is all I need a Voltage Divider circuit with the ability to handle enough power? To my poor lil’ mind, based on the 200 Watts into 8 ohms an amp would put out 40V; and if I do the calc with 4 ohms I get 28V. Anyway, what with normal audio levels vs. the power required, and a good margin of safety (e.g., not allowing a teenage boy - including my inner teenage boy - to take over any volume controls), my guess is that 1/25 Voltage Divider would give me a nice input range to the computer sound card for this analysis.
I’d think I could use the following 10W resistors safely: http://www.radioshack.com/product/in...ductId=2062292
They are 50 ohm, there’s also 10 and 1 ohm 10W models. Put two of the 50s in parallel with a 1W below the outputs. One of the 50s with two 1’s in series below would be half the current – Might that be better?
Or is there a problem with that much resistance total, and I should try to mimic an actual speaker impedance? Both of these give me a 1/20 voltage division: a 10 ohm above and two 1’s in parallel below (10.5 ohm ckt), or even go to two 10s in parallel and four 1’s in parallel below (5.25 Ohm)?
Thanks in advance!
And for those who aren’t totally bored yet, this is a post with an Appendix! (it’s not important to the original question, but perhaps of interest or worthy of separate discussion): What I want to do is to look at the electrical signal to be able to measure and characterize the noise in my signal chain and try to diagnose if the majority of noise is coming from an amp, the preamp (or AVR, etc), earlier in the chain, or from power, or from cable interactions, RF interference, etc. And do this without having to account for the speaker, room (including ambient noise), or microphone (including repeatability of setup – location and orientation).
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