Setting gains with multiple devices

[fly_marlin]

Oh I see what you're saying. Yes, use the sub-out on the re-q so that you can use the subsonic filter.

 

[Sizzlechest]

What exactly does that do, and is it better to use the re-q without my separate crossover? The crossover I have is Sound Storm SX310.

 

[fly_marlin]

It is essentially a high pass filter and I believe it has a steeper slope than a HPF. You should generally set it to 1/2 octave below the tuning frequency. So if your box is turned to 36Hz, 1 octave below that is 18Hz, half of that is 9Hz, so you'd set your subsonic filter to 36-9=27Hz.

Generally speaking, if you think your LOC has enough flexibility, take out the x-over. There are acoustic disadvantages with having additional components in your setup. However, if you think the x-over gives you the needed additional flexibility, then leave it. If the LOC already does everything you need it, remove the x-over.

 

[Sizzlechest]

Ok I prefer to have the crossover in place because I have a remote gain control (for the crossover) mounted up front and my gf hates the bass so I like being able to easily turn it down for her.

Here's what I found on the net for my devices. Can I mathematically determine the approximate gain setting based on each devices specs?

re-q:

re-Q Specifications

Gain dial has 0.0-2.5

In spec sheet:

Output Channels: Left, Right, Sub

Output Type: Unbalanced RCA

Max Output Voltage: 2.5V RMS Full Range, 8V RMS Sub

Signal to Noise: >90dB (A-Weighted referenced to 1V out)

THD+N:

Crossover Sound Storm SX310

http://images.soundstormlab.com/manuals/SX310_EN_UM.PDF

Output voltage: 8Vmax

Output gain: 1:2 +6db

PPI A600.2 art series amp

http://www.precisionpower.com/Manuals/Amplifier%20Manuals/Precision_Power_Art%20Series%20Axxx.2%20Amplifiers.pdf

Input Sensitivity: .2 - 2.5 V

 

[fly_marlin]

You should set everything at 2.5V. If you're able to select the output voltage on the x-over, set it to 2.5V. If you set it higher, you will overdrive the signal as your amp only accept 2.5V max. Consequently, as noted earlier, you will need to set your amp to the minimum sensitivity setting.

 

[Sizzlechest]

Minimum sensitivity is all the way down or all the way up?

Do you know where approximately that is on my crossover gain based on the above specs?

 

[fly_marlin]

Usually minimum sensitivity (2.5V in your case) is all the way counterclockwise.

 

[Sizzlechest]

So my PPI amp will be set all the way down? It's not going to output anything though? Are my other gains supposed to be maxed then?

 

[fly_marlin]

Do any of those devices have an output voltage setting?

 

[Sizzlechest]

No, just gain

 

[fly_marlin]

Yea, so then set everything to 2.5V across the board.

 

[Sizzlechest]

re-q:re-Q Specifications

Gain dial has 0.0-2.5

In spec sheet:

Output Channels: Left, Right, Sub

Output Type: Unbalanced RCA

Max Output Voltage: 2.5V RMS Full Range, 8V RMS Sub

Crossover Sound Storm SX310

http://images.soundstormlab.com/manuals/SX310_EN_UM.PDF

Output voltage: 8Vmax

Output gain: 1:2 +6db

Re-Q outputs 0 to 8V? And same with crossover? So should they both be at about 1/4? I am now using the sub output on Re-Q.

 

[fly_marlin]

On the re-q, it should be set to whatever the deck is, no idea what that is. I'd just leave everything at 2.5V. Don't max out re-q.

 

[Sizzlechest]

The deck has only a volume knob. (it's a factory radio)

The Re-Q has a dial from 0 to 2.5

The crossover and amp have no numbering on their dials, but I believe we know the output ranges?

With that, can you tell me the approximate setting (from 7 o'clocl (lowest) to 5 o'clock (highest) Is there any way to see what the output voltage is with a multimeter?

The PPI has a max input sensitivity of 2.5V, so if I set the other 2 devices to what I believe is 2.5V, where should the PPI amp be set at? 0\7o'clock?

 

[fly_marlin]

Re-q set to 2.5. If x-over goes from about 0 to 8, then 12 o'clock is about 4V, so I'd set it around 10:30.