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SpiderBy
05-17-2009, 08:26 PM
Hi folks,

Decided to ask my dumb question here.

Never had a sub before so it was my first install.
And I also chose a bumpy road of building a custom fiberglass sub enclosure.
And finally I did it (I gonna post a write-up of that adventure in a while)!

Today I finally hooked up my mono-amp Alpine MRP-M500 with my 10" Alpine Type R sub (1022D). Well, finally listening to a low & clean bass was a good compensation for the effort.
But since there is no perfection, I started to hesitate that I chose not the right sub :)

The problem is that it is dual-voice-coil 2 ohm sub and since I hooked up it in series with the amp it goes with 4 ohm load and 300 Watt RMS. And I can't connect it in parallel cause it would mean 1 ohm load for amp which is not recommended.

It seems I should have chosen Alpine 1042D sub which I could connect in parallel and get 2 ohm load to the amp so it could drive 500 Watt RMS.

Guys, please tell me if I really made a big mistake.
Will I hear a significant difference if I replace my 1022D sub connected in series with 1042D connected in parallel? I am not much in getting streets blown, I just would like to get a nice clean bass with my setup and be sure I made it right.

koolade9
05-18-2009, 10:41 AM
You didn't necessarily make a "bad" decision... could you get more out of your system...yes.

If you double the power to a driver, you effectively double the output (3db increase). If you add a 2nd driver, using the same power, you also double the output.

In your case, switching to a dual 4ohm driver (capable of 250wrms/coil) you'll effectively see a 66% increase in ouput (based on alpine's rated power). In my opinion...do it! [up]

To ensure your sub lasts as long as it should, ensure your enclosure is of proper size/construction. Any leaks or mis-tuning can cause distortion...and distortion is what blows drivers.

SpiderBy
05-18-2009, 09:29 PM
Thank you for the comment.

My enclosure seems good, though it resulted in a minimal recommended volume (0.5 cu. ft.) for the sub to fit the area at left in the trunk behind the trim, I added some "poly fill" and it sounds solid. I also checked there were no any leaks.

I found out that I have to set almost the full gain on the amp for the sub to sound better so I am really thinking I'd better to get a 4 ohm sub instead.

Thanks again and my write up with photos is yet to follow!

surfntomm
05-19-2009, 01:48 AM
If you double the power to a driver, you effectively double the output (3db increase). If you add a 2nd driver, using the same power, you also double the output.

.

I just wanted to clarify that doubling the power will in fact increase the SPL by 3db but that is not twice as loud. (doubling the output seemed vague and was how i interpreted it, not sure if thats what you meant). for something to be twice as loud it needs to be about +10db

in summary 3db increase requires double the power
to be twice as loud you need +10db

cheers [drive]

koolade9
05-19-2009, 05:20 PM
I just wanted to clarify that doubling the power will in fact increase the SPL by 3db but that is not twice as loud. (doubling the output seemed vague and was how i interpreted it, not sure if thats what you meant). for something to be twice as loud it needs to be about +10db

in summary 3db increase requires double the power
to be twice as loud you need +10db

cheers [drive]

+3db IS twice the output, period.

+10db being twice as "loud" to the human ear is a perception, as everyone's hearing is different. This varies across frequencies as well.

Bibs
05-19-2009, 06:16 PM
+3db IS twice the output, period.

+10db being twice as "loud" to the human ear is a perception, as everyone's hearing is different. This varies across frequencies as well.

[;)]

and in a perfect world