Kurack

I have 2 10" Boston Aucustics G5's subwoofers. I replaced my 2 x12" Fosgate subs which were running off a P6001RD (which i still think wasnt enough). The BA's sound like **** on this, and I think I am way under powered here.

What do I need to look in for an AMP to power 2 of these 10" G5's?

Specs on the BA website, but I see this on the sheet.

1 G5 = RMS POwer Handling 450w / DUal 4ohm, Tuning freq 34hz

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BLACKonBLACK98

car audio section?

lets see... 450w rms x 2 = 900 rms (at least).

underpowering subs will not cause them to sound like s**t. high gains (clipping) will as well as a bad install (incorrect box size).

Kurack

Well, its not that they sound like ****, its that they are not loud, not much bass at all.

How do I tune the high gain clipping? I'm a noob in the actual sub/amp stuff, not PC stuff though.

Free free to move the thread, I missed the car audio section, sorry

Kurack

Would any of these amps be enough? Most have 1000+RMS but only at 1x2ohm I think.

http://www.bestbuy.com/site/olspage....=1198888991131

http://www.bestbuy.com/site/olspage....=1199494646259

BLACKonBLACK98

wanna try that amp model number again? i can't find anything on it (brand/model number). you may be able to wire it down to 1 ohm to get more power but i need the amp info.

my other recommendation would be to get out of best buy. there a slew of internet companies producing higher quality goods at lower prices. you can also get almost anything cheaper in other online stores (although i will not recommend anything that is an unauthorized sale).

lets take it 1 step at a time though. amp specs?

Kurack

I only said best buy cause I'm really wanting to get my setup 100% for today....but here goes

My current Sub AMP for the 2x12" Punch subs I was running is a :

Rockford Fosgate P6001BD (sorry had typo above, not 1RD its 1BD). Its the one with the metal sides, this is the exact one I have, http://cgi.ebay.com/NEW-Rockford-Fos...QQcmdZViewItem

Here it is physically installed in my car, on the right of this picture:



Here is a picture of the new box installed with the G5's:

BLACKonBLACK98

ok heres some issues:

1) because you have 2 dual 4 subs you can't wire to 2 ohms... meaning you are probably running at 4 (300w).

2) that amp is not 1 ohm stable so you won't get the power you need out of it.

3) hopefully the box is within specs.

so if you really must go to best buy and make it happen today i would say the alpine MRP-M1000, but if you have any local mom & pop stereo shops i would start there. theres much better equipment out there.

what you need:
1000w rms @ 1 ohm

ThePistonDoctor

Kurak, there are still some questions we need answered before we can give you an accurate answer. You may not need a new amp. First of all, those subs are available both in single 4 ohm AND dual 4 ohm, which do you have? If you have dual 4 (two terminal connections on each sub), it's correct that you can't wire down to a 2 ohm final load. HOWEVER if you have the single 4 ohm version (only one set of terminals on each sub) you CAN wire to a 2 ohm load and get twice as much power.

Also, what you're describing sounds more like a wiring issue than an amp issue. Clipping would most likely cause your amp to go into protection mode and shut down so I don't think that's the problem. If you have accidentally reversed the polarity (even the pros do it...accidentally connected the negative to the positive and vice versa) your subs will sound VERY quiet. Doesn't matter if you throw 3000 watts at them, if the polarity is wrong they will sound like they're almost off no matter how much you adjust the gain/volume/EQ settings.

I would check your wiring, make sure it's all correct. Also, let us know whether you have the dual 4 ohm or single 4 ohm subs because you may be able to get the load you want by just changing the wiring. If all this fails, I will resort to saying Rockford amps suck balls...which I will actually say anyway. You should not be powering those subs w/ a garbage amp from best buy. Not trying to insult you, just saying the subs will sound and perform MUCH better with a high quality amp on them

techy101

The choice of subs is going to make it hard to get high SPL. They have a 1w/1m sensitivity of 85dB. Having two of these, both at redlining at 450 watts, under perfect conditions (i.e. a sine wave generator) you will still only have a maximum possible SPL of ~108dB SPL at listening distance. If you were to shove your face 1 foot away, you would get ~125dB, but that's not a usable measurement since you don't drive in your trunk

Real world, I wouldn't expect you to be able to reach a continuous output over ~105dB SPL. Better subs (read: more efficient) would go a long way to creating higher levels, and would be a more worthwhile expenditure of your money IMHO.

Also, the difference between a 450w / channel amp and the RF amp you have linked to above will only be a maximum change of 1.5dB SPL/chan, so a total of about 3dB SPL. And again, that's if you were actually running at redline. Which you aren't, and very rarely will. Is 3dB SPL really worth the money to you?


Just an example, if you got a set of subs with a 1w/1m sens. rating of 90dB SPL, the same 450 watts/channel would give you ~113dB. If you got a high efficiency set that were rated around 95 dB SPL @ 1w/1m then that same 450 watts/channel would give you 118dB.

In contrast, to make your subs (theoretically, if it didn't exceed their power handling/cooling ability) that same 118dB SPL at listening distance would require you to have an amp that was 4500 watts per channel!!!

I should also note that these numbers are all in perfect conditions. They're based off numbers measured in an anechoic chamber. ALL real world numbers will be lower because of material absorption, and other obstacles between you and the speakers.

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Kurack

Ok so the G5's I got have only 1 set of terminals on them , BUT, the box/model that I have says "Boston G5 10, Dual 4ohm Voice Coil.

I checked my wiring, I got from each of the negative on my sub amp to each of the negative on the subs, same for positive. THe subs just done thump hard...barely noticable <hmmm>.

All I want is nice thump, nothing award winning....these subs should do it. I think this amp might have issues also...never seemed to get real thump using it...but my last 2x12"'s thumped decently with it though.

I will post pictures of the subs closer

techy101

This statement is very contradictory. You're saying that the amp doesn't give you your desired results, and you think there might be something wrong with it, but it did give the desired results when paired up with a different set of subs. You just pointed to the subs being the most likely cause of the change and unsatisfactory performance.

The numbers I posted above are not award wining. they're real world numbers for what you're calling "thump." Also of note is the fact that one higher efficiency sub would generate higher SPL's than the pair of these.

Also, after a bit of a closer look at the pictures, those numbers are a tad on the low side. Between 1.5 and 3dB SPL low. I didn't realize how close the subs were to your listening position.

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Kurack

Picture of the sub:



Picture of the label. Hard to read by says "Dual 4ohm voice coil":



Both wired to the amp:



Back of amp. I never know what to set the xover freq to, but i play with it to no avail:

techy101

ignore this post. I'm smoking crack today, I was looking at the diagram upside down

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Kurack

I guess I should have rephrased that. I'm getting barely any thump at all with these new ones. Everything wired the same as old ones (im goign to bring old one back out and rewire it to see). This is why i think the amp is the problem perhaps? I guess I am sayign that I dont understand or follow anything about dB...etc. Your numbers above mean next to nothing to me <sorry, they just dont>.

I guess to my original question a bit more....based on the amp I have that is powering these G5's....is it sufficient? My guess is no. If you had these subs, what amp would you be looking at to use with them <links to buy online would be cool>. The other amp i have for all the other speakers in the car (fosgate) is running good, no issues.

I appreciate all the help you guys are giving me....getting me closer to understanding and getting this fixed (if its an under powered amp)

techy101

It would be worth your time to do a bit of research on audio then. It can save you lots of money, and give you higher performing systems at the same time. (talking to a sales guy at best buy doesn't count. They're (mostly, not all) idiots and have no clue how things will really perform besides the big number posted on the box)

I'm not just being an *** btw. A well engineered system can cost less than half of a poorly designed system, and provide better results in less space, and it applies to everything from car audio to home theatre to PA to concert systems.

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