Input sensitivity?

[JBL 4645]

Question for you boputnam

I was reading the post that richluvsound posted about the Lexicon amplifier and something got me thinking about the (input sensitivity).

Now I know this place is to learn and yes, I’m still learning. This thing about voltage as described in the (picture).

Input sensitivity (balanced and unbalanced) so question does this have something to do with the signal travelling form the Kenwood AVR to the DCX2496 to the Alesis RA300 as there rated at (150watts into 4Ω and 90watts at 8 Ω).

Most times it doesn’t sound like I’m pushing even 50 let along 100 or close to 150watts, am I doing something wrong here.

Alesis reference manual specifications.

Alesis RA300 input sensitivity +4dbu (1.23v) for rated output with input control at maximum +26dbu

Thanks.

[boputnam]

The input voltage required to drive the amplifier to full rated output power at maximum gain. Usually expressed in Vrms (Volts RMS).

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from the QSC Glossary of Audio Terms - a great resource.

[JBL 4645]

bop

Thanks for the reply.

I’ve stumbled onto this (QSC) page or a different one in the (QSC) range earlier this year. I looked under I for (input voltage) but like the saying goes in Grease “tell me more tell me more” I have a basic (voltage metre) so how do I go about at setting the voltage that will arrive at the (Alesis RA300)?

Shall I use a sine wave generated from my (Denon CD)? Or use a sine wave tone generated from the TrueRTA as there is a sound generator to send out a (pure sine wave tone).

What setting shall I set the voltage metre to, and where to place the (positive and negative terminals) do I place them on the (RCA phone outputs) and get a reading first?

Or do I place them on the outputs of the DCX2496 and take the reading from there, and take voltage readings from both the (LF and HF outputs)?

And thou I’ve been setting the volume levels on the (RA 300) and different levels the levels of the volume controls at present are 1/5 of the way up or (9 o’clock position) for (LF outputs).

The sub bass output to drive the JBL 2240 sub is around the (2 o’clock position).

But since reading this voltage caper in the other thread I just got a little concerned that’s all.

Peace and

[boputnam]

...so how do I go about at setting the voltage that will arrive at the (Alesis RA300)?

You don't have to do a thing.

The input sensitivity of that Alesis Reference 300 is 1.23V (+4dBu) - call it "pro" (as opposed to consumer at -10dBu). I'm guessing you are coming out of the Kenwood's "PRE OUT", which has a 1V/1kΩ output level/impedance? You should be fine. There is no "adjustment" to make.

And thou I’ve been setting the volume levels on the (RA 300) and different levels the levels of the volume controls at present are 1/5 of the way up or (9 o’clock position) for (LF outputs).

The sub bass output to drive the JBL 2240 sub is around the (2 o’clock position).

This question is a bit more tricky. The two outputs need to match your desired taste, or as measured with an RTA.

At home, I run my amps wide open. I have no satellite sub, and use no tone control. So, the output signal is as-from the source. Gain is controlled by the pre-amp.

In SR, I run the amps at "system" 0dBu - that is to say, I send a 0dBu signal from the console and set the amps gains to match that (mains are unplugged during this - LED's only). So, when I see 0dBu at the desk at Front of House (FOH), I know the amps will be hitting 0dBu (even though 100-ft from me where I cannot see them).

"9 O'clock" or "2 O'clock" mean nothing. This is only relative (and relevant) to those two units you are using, the way you are using them - it is not quantifiable will not translate to any other system.

[JBL 4645]

bop

So in a nut shell I don’t have to worry myself is that not correct.

Thanks.