3 replies to this topic

[Gizzards12]

Guys,
Im using the Alpine PDX-M12 to power a Morel Ultimo 12" 2ohm single voice coil sub in a sealed 50ltr (1.7cf) box. I have the gains turned up full to acquire some head room on the sub control. To acquire some sub control I have time aligned forward and pulled the front and rear 6.5" splits back by 6db. The Alpine PDX-F6 is producing 187rms per channel. I have managed to pull a fantastic sound but am sure there should be more sub head room as the M12 is producing 1297rms @ 2ohms plent right? Wrong.
My question are

Is the Alpines IDA-305S head decks output voltage (piss poor 2v output) to low For the M12 @ 2ohms ?
Can this can cause a problem with the gains and output level?
If so how do I increase the output voltage short of buying a new deck?

This just came to me and thought I'd ask for opinions and tech advice?
When I had the old Alpine Mono V12 600rms @ 4ohms running a 4ohm 425rms Polk mm series 12" sub I didn't have any gain or sub control issues, it just wasn't detailed or loud enough.

Cheers
Az

Edited by Gizzards12, 08 April 2012 - 09:42 PM.

[shiny_car]

I don't quite know what you're meaning, or understanding, by the term 'headroom'. To me, headroom is reserve power, used for peaks. And therefore what you are hoping to achieve by increasing the gain setting (other than potentially pushing the amp into clipping).

Also, what do you mean by "sub control"? How is it 'uncontrolled'? Are you referring to how it sounds, or simply adjusting the volume using the sublevel contoller?

Sorry, not having a go at your terminology (cos there isn't any really uniform terminology!), but trying to understand what you find the deficiencies in your system are, and how to fix it. "Fantastic sound" but need more "headroom"?? I suspect you are meaning that the subbas isn't loud enough.

The output voltage of the 305S should easily be enough to drive the M12 to full power output when the gain is set correctly. Though I doubt it needs to be set anywhere near at full, unless your iPod recordings are recorded at an abnormally low level. So, with gain set properly, and full volume on the 305S (35/35), it should easily be enough to achieve full power output; set the gain too high, and the amp will go into clipping. Again, I can only see a problem if the recording is the problem.

I think I mentioned it in your Builds thread: if the subbass isn't loud enough, you may need a second sub and amp. Being a large wagon, a single sub setup may not be enough to meet your needs.

If in doubt, have the system assessed by the store you bought the gear from.

[SSSpoosah]

http://www.mobileele...volume-control/

I don't know if this may help you, because I think you may be taking gains the wrong way.

As for the pre-out voltage of the head unit, it would be better to have higher than 2v, usually to reduce possible noise issues mainly. Without the head unit being changed, you can use a line driver. Or if you are planning a processor, most of the ones I know will actually boost the HU pre out voltage if required (usually to 5v). That being said, what Shiny said is true, if the gains are set correctly it will not constrain the power of the amp

Edited by SSSpoosah, 09 April 2012 - 08:22 AM.

[Damo95]

The location of the sub could also be the culprit, as it's close to the tailgate and not able to "load" correctly..

In my wagon, I've got an idmax powered off a PG tantrum 1200.1 (birthed at 1418wrms @4ohm) and it's loud.. Not loud enough to win spl comps bit loud enough for my everyday needs..

Have you tried the sub in a different box, in a different location?

Damo95 posting on iphone