problem with subs

[thakurtis]

i have 2-12" memphis 3124D subwoofers (DVC) that arent as loud as they should be. one of my friends has some and they are extremely loud. Im not sure if my amp isnt powering them right or what but if all else fails im just going to get a memphis 1000D amp.

My amp is a Sony XM-SD51X
Mono car subwoofer amplifier (Class D)
1100 watts max power.
250 watts x 1 RMS into 4 Ohms

my subs are wired at 4 ohms and the max is 300rms

my friend has a different amp with the same specs as mine but his subs are so much louder. anyone know what might be wrong?

[Scarrell]

ok so if you are sure you have them wired right, they are each getting around 125rms a piece.. (assuming you have them wired right), anyway... theres alot to take into consideration here... cd player, the box and the car.. and how you each have your settings set....

[William from NOLA]

Keep in mind that the Sony amp you have is VERY overrated. What amp does your friend have?

That Memphis amp you mentioned will be a drastic difference to the subs.

[Ryan from Ohio]

Its the amp.

This is that night and day difference between cheap vs. quality equipment you will see mentioned throughout this forum.

Box can be part of it. Also different vehicle=different acoustics. But I think 90% of it is the amp.

Them Sony amps are world renowned for being crap ;)

[Darthness]

laugh, only 250watts RMS?!

[smoker]

even if your friend had the same amp you can expect different results unless everything else were identical..enclosure,wiring,head unit, rca's and even the car...your car will have an effect on how your speakers play because of the cars interior shape this is called cabin gain..your vehicles layout naturally effects certain frequencies differently than other cars will by naturally boosting some areas....

[thakurtis]

i was told to wire them at series parallel and i looked at a few diagrams so im sure i wired them right, but they dont sound any different than when i had them wired just regularly.

My head unit is a this JVC if it makes any difference http://www.jvc.com/product.jsp?modelId=MODL027441&pathId=54&page=1

The box is 1.25 cf per chamber and i think thats the recommended for sealed boxes but im thinkin im going to get a ported box.

My friend with the same subs also has that memphis amp i want to get- so that might be the problem. The stats are the same on both amps but i guess the sony just doesnt power the subs as good as the memphis.

and just out of curiosity.... are there any differences between wires/amp wiring kits or can i just buy the walmart brand and get the same outcome?

[jonnyb]

are there any differences between wires/amp wiring kits or can i just buy the walmart brand and get the same outcome?

depends on who you ask. http://www.knukonceptz.com/ makes decent, low cost wiring kits.

[GlassWolf]

definitely the amp. possibly the enclosure, too.
If you want more SPL, and better sound overall, I'd suggest getting a much better amplifier (read: NOT Sony) and go to a ported box, about 2cu ft per 12" sub, with 4" or slot-vent ports tuned to about 34Hz.
you'll get much better results. Like night and day.

[thakurtis]

thanks you guys really helped me out alot


one more general question....... how do you all have your sub boxes anchored/braced?

[GlassWolf]

mine is anchored to the car, but since I fabricated some of the interior anyway it wasn't hard to weld in a couple of tabs for securing the enclosure, which has 120lbs of subs in it anyway, along with a load of MDF. I'd be surprised if someone could move the box, let alone get it out of the car. It's mounted just behind the jute board for the trunk divider in the car's trunk, so it's not visible from front or back anyway though. The speakers are concealed within the enclosure behind membranes due to the design of the box.

[bigbassman]

mine's anchored with lag bolts, strapping, screws, and glue..

overkill? nah... I don't want a 500 lbs wall coming loose :)

Loyd L.

[GlassWolf]

mine just wouldn't have anywhere to go even if it did.
the flush mounted amplifeirs brace it from behind in a false floor.
the jute board in front of them is MDF and latched closed.
nowhere to go.