Boston Acoustic

Ok another question. If i am not going to worry about the back speakers, would it be wise just to get a good 4 channel amp and drive the fronts and the sub off of it? Whats the best 4 channel amp SQ wise for around $400-$450 or so.

 
What does this mean. 4 Ch. Power @ 4-ohm (12vdc) 85 Watts x 2. whats the difference between that and 4 Ch. Power @ 4-ohm (CEA-2006-A): 100 Watts x 4

when looking at signal to noise ratio higher is better right?

Does THD at Rated RMS Power mean a lot?

 
What does this mean. 4 Ch. Power @ 4-ohm (12vdc) 85 Watts x 2. whats the difference between that and 4 Ch. Power @ 4-ohm (CEA-2006-A): 100 Watts x 4
when looking at signal to noise ratio higher is better right?

Does THD at Rated RMS Power mean a lot?

That first rating is at 12 volts, the second rating is at 14.4 volts. You'll be right in the middle more than likely but the difference wont be audible from 85w to 100w. I think the "85x2" is supposed to be 85x4 if its a 4 channel amp, could just be a misprint.

Higher Signal Noise Ratio is better, but dont look into that too hard.

Also, look for low THD at rated power. THD = total harmonic distortion iirc...distortion = ghey

 
I'm running 1 G3 12 inch with a Boston 500m mono sub, clearly a different setup but I can say from my experience that Boston makes very quality gear and you likely aren't going to be let down with one of their amps.

 
Also, look for low THD at rated power. THD = total harmonic distortion iirc...distortion = ghey
THD at rated RMS wattage is almost always 1%. If there is vendor literature that claims 0.05% THD or something similar at rated RMS wattage, they're almost certainly bullshitting you or their marketing people have no clue. This is because there also exists a test that measures THD at 1watt. This is usually "the amplifier THD". That number is usually very low. A lot of manuals confuse the concepts and claim that the later number is the THD at the rated RMS wattage. A lot of posters confuse these things too. I have seen many times comments like: "What, your amp has 1% THD? It's a piece of crap!"

Note that some companies that fancy themselves as being high end vendors provide RMS wattage only as measured up to 0.5% THD. I don't like that because this does not give you apples to apples comparison with amplifier watts measured at 1% THD. Moreover, there are also many amplifiers where once THD goes up, it _really_ takes off, so if the rating is 60watts at 0.5%THD, chances are good that you will get at best 70watts at 1% THD, an inaudible difference. A THD plot often looks like this:

http://www.pasmag.com/images/stories/test_report_graphs/1304/precision_power/image1.jpg

So just because someone measured RMS wattage up to half percent THD, it's not necessarily cleaner than amps with similar wattage up to 1% THD.

 
Boston GT 4100 -----------> Amazon.com: Brand New Boston Acoustics GT-4100 900 Watt RMS GT Series 4 Channel Class AB Car Amplifier: Car Electronics1-Ohm Stable: The GT-4100 can be connected to loads with impedances as low as 2 Ohms mono. The lower the impedance, the higher the output power:

100 watts x 4 @ 4 ohm

150 watts x 4 @ 2 ohm

225 watts x 4 @ 1 ohm

450 watts x 2 @ 2 ohm

100 watts x 2 @ 4 ohm stereo + 450 watts x 1 @ 2 ohm mono

Perfect for a set of comps up front and a JL w6 sub.
That is a nice amplifier. I believe a lot of GT series amplifiers were actually clones of some Italian amp and were built in Italy. However, this is still a Class A/B amplifier. You can expect it to run relatively inefficiently, and often hot. Someone reported the thing having thermal shutdowns in a car being driven in Florida on sonicelectronix I think (could be a review of the 5-channel version of the same). Of course, it could have to do with the install. I would certainly not run it bridged at 2ohms. That's just asking for trouble. This could be an interesting project for CPU overclockers with experience in setups with liquid cooling ;p

 
wow after reading all the specs on the 4100 Width: 22 1/4” (566mm)I don't know where id install it in the Jeep Liberty. Looking under my back seat i doubt there is that much room. I also didn't realize that the 5750 and 1105 where that big also.

will all 4 channel amps run a sub and component speakers?

 
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That is a nice amplifier. I believe a lot of GT series amplifiers were actually clones of some Italian amp and were built in Italy. However, this is still a Class A/B amplifier. You can expect it to run relatively inefficiently, and often hot. Someone reported the thing having thermal shutdowns in a car being driven in Florida on sonicelectronix I think (could be a review of the 5-channel version of the same). Of course, it could have to do with the install. I would certainly not run it bridged at 2ohms. That's just asking for trouble. This could be an interesting project for CPU overclockers with experience in setups with liquid cooling ;p
I ran mine at 2 ohms bridged daily. Never even got really hot to the touch. Certainly never shut off. Mine was an older Gt though...but seems to be the same technology and yea they were clones of Audio system twister Amps.

 
wow after reading all the specs on the 4100 Width: 22 1/4” (566mm)I don't know where id install it in the Jeep Liberty. Looking under my back seat i doubt there is that much room. I also didn't realize that the 5750 and 1105 where that big also.
will all 4 channel amps run a sub and component speakers?
If you're worried about size, etc, get a PPI Phantom amplifier. PPI P900.4 provides honest power as rated for 4x140watts at 4ohms or 450watts in bridged mode. Sonicelectronix has the 4-channel version for $200 shipped right now minus a 10% discount if you enter the "PPI10" coupon code, if it hasn't expired yet. I bought mine for $230 and I thought it was worth that price. There is also a 1-channel PPI P1000.1 and 2-channel version PPI P600.2. Unfortunately, the 5-channel PPI P900.5 hasn't reached the vendors yet. A lot of people are waiting for it. IMO, this PPI line is going to lay waste to MB Quart ONX4 and similar budget amps unless the competitors hurry up with their own budget full range Class D amplifiers.

The four channel PPI P900.4 has enough power for pretty much any component speakers. If two channels are bridged, it will give you 450watts with 14.4V battery, around 360 with 12V (engine off). This is plenty for a lot of subwoofers. The only problem is that your sub has to be wired for 4ohms. (a few high end subs, like JL Audio W6 are not available in DVC 2ohm form that's compatible with this). I can suggest a list of subs that will run fine with 400watts at 4ohms since I was recently shopping for a compatible subwoofer for a 1cu ft sealed box.

 
Thanks a ton for all the info guys.

So the JL Audio 10W6v2-D4 and Dayton Audio RSS265HO-4 10" are 4 ohm and it would work with this amp? Both are 600 wrms. The JL is twice as much as the dayton. Is the JL that much of a better quality sub or is it the name that costs extra?

The 900.5 says RMS Power 4Ω Bridged 230 x 2 & 440 x 1. Would that do what i want it to?

It looks as though this place is selling them

http://infiniteelectronix.com/precisionpowerp9005phantom70x4270x14ohmscompact5-channelclassdamplifier65x115x2.aspx

 
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Ok unless you all can think of something better, i'm going to either go with.

Precision Power Phantom P900.4 4-Channel Class D Full Range Amplifier or

Hertz HDP 4 is a D-Class four-channel amplifier. (can't find it for sale)

Thanks for your input.

 
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Thanks a ton for all the info guys.So the JL Audio 10W6v2-D4 and Dayton Audio RSS265HO-4 10" are 4 ohm and it would work with this amp? Both are 600 wrms. The JL is twice as much as the dayton. Is the JL that much of a better quality sub or is it the name that costs extra?

The 900.5 says RMS Power 4Ω Bridged 230 x 2 & 440 x 1. Would that do what i want it to?

It looks as though this place is selling them

Precision Power P900.5 Phantom 70 x 4 + 270 x 1 @ 4 Ohms Compact 5-Channel Class D Amplifier 6.5x11.5x2
The JL w6 is dual 4 ohm which means you will be wiring it to 2 ohms final so you'll want an amp to push it at 2 ohms. (Which is why I was suggesting the Boston GT)

The Dayton is Single 4 ohm so you will need an amp that does the power it wants at 4 ohms.

If you really want to run one amp, you'd probably better go with a 4 channel amp. Reason being, with the w6, not too many 4 channel amps are bridgeable down to 2 ohms to push that sub. Most of them are only stable bridged down to 4 ohms. In the case of the Dayton, it is single 4 ohm so finding an amp to run it wont be as hard but finding one with adequate power for it bridged at 4 ohms might be. That is why, IMO, if you want to run one amp, go with a 4 channel bridgeable down to 2 ohms like the Boston GT or a nice 5 Channel amp.

In regards to the price, having had experience with both woofers, I'd say it really depends on what you want. The w6 can be put into a slightly larger than "recommended box" and raise the efficiency and wont need as much power to get it making some noise. The Dayton, on the other hand, likes TINY enclosures and is not the most sensitive sub so it'll need more power than the JL will to achieve the same level out output. In my opinion, thats the main advantage the JL has over the Dayton. But, that is also dependent on your listening preferences. I may like more bass than you do or vice versa. But, remember, it is always better to have too much bass and turn it down that not enough and end up blowing something trying to get more output. Whether or not you feel the price difference is reasonable is up to you. But, in my personal opinion, and again from experience, I'd pay the online prices on the JL w6v2 as they are amazing woofers. But, the Dayton is also great. You cant go wrong either way.

For an amp recommendation, I'd say the Alpine PDX 5 is a great candidate. Small enough to fit anywhere with very nice power and sound pretty nice as well.

Buy.com - ALPINE PDX-5 Car Amplifier - 75 W RMS - 5 Channel - Class D

Since it does constant power on the sub channel at 4 or 2 ohms, you can use either the Dayton or JL sub. But I'd have to think the JL would give you more output on that amount of power.

 
I've read a lot of opinions and think i might have come up with a setup.

HU:Kenwood 955

fronts:BA sc-60

backs: stock infinitys

Amp:precision Power P900.4

Sub: Dayton Audio RSS265HO-4 10" Reference HO

If i go with the PPI i can afford to buy the sub and bridge the amp to power it.

Anyway that's what it sounded like to me from what I've read.

I don't have room for the BA amps or I'd get that.

Please let me know if you think I could do better.

Thanks

 
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