QuestionQUESTION: I currently have a 2 ohm single coil 1000W (500W RMS) and I am looking to add another subwoofer and to purchase an amp. Am I required to have another single coil sub to match or can I use double? Also, do I need to stick with the 2 ohms for the new sub or should I go with 4?
ANSWER: Hi Trent,
Ideally, you'd want your second sub to be as closely matched with the first sub as possible.
The trouble with mixing sub types is this: if you're using a 4-ohm sub and a 2-ohm sub on a single amplifier, the 2-ohm sub will use more power than the 4-ohm sub. You'll end up with two subs playing at different levels, and it's hard to predict how that will affect your sound quality.
Even if you pick two subs with the same voice coil and impedance setup, you might still end up with a level mis-match if one sub is more sensitive than the other. If the two subs have different power handling characteristics, you might damage one from over-powering before the other reaches its' maximum output potential. If they have different T/S parameters, and they're sharing the same box, they might react differently to the box volume.
In general, the best choice if you want to use a subwoofer pair is to pick two identical subs.
If you do end up with two single voice coil, 2 ohm subs, then your best option might be a 2-channel amp rated between 300-500 watts RMS per channel at 2 ohms. If you select a mono amplifier, you'll need to be sure it's stable with a 1-ohm load.
What kind of sub do you have now? There aren't many subs out there with specs like you're describing.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: I have a JL 10W3v3-2 SVC 1000W 10" subwoofer. Most amps I see are 4 ohm amps. If I buy a twin for my JL sub, I will have 2 SVC 1000W each (500W RMS each) subwoofers...I should not buy a 2 channel amp with 4 ohms at 1000W? I haven't seen very many 2 ohm amps out there.
AnswerActually, most amps that you look at will have different power ratings for different load impedances. Most 2-channel amps can operate with 4-ohm or 2-ohm loads in stereo mode, and they'll usually have different power ratings for each. For example, look at the specifications on this amplifier from Rockford Fosgate:
http://www.pioneerelectronics.com/PUSA/Support/CarAudioVideo/Source/CD-Players/c
You'll see that it's rated for 200 watts per channel at 4 ohms, and 300 watts per channel at 2 ohms.
Mono amplifiers will also carry different ratings for different load impedances. Almost all mono amps will be rated at 4 ohms and 2 ohms, and some will be rated at 1 ohm.
If you're looking at 2-channel amps, you'll want to look at 2-ohm ratings. You'd be operating the subs in stereo mode, so the "bridged" power rating isn't relevant.
You may actually have better luck finding a 1-ohm stable mono amplifier. If you combine two 2-ohm subs on a mono amplifier, it's best to wire them in parallel. Wiring multiple drivers in series is not recommended. That means the total impedance at the amplifier will be 1 ohm.
According to JL's web site, the "optimum" amplifier power rating for that sub is 300 watts RMS. You definitely wouldn't want to use an amp rated higher than 500 watts RMS. If you use a mono amp, the power output will be divided between the two subs; so the ideal mono amp power rating would be 600 watts at 1 ohm, and no higher than 1000 watts RMS at 1 ohm.
The Rockford amplifier I linked above would be a good match for a pair of those subs. Some other amps that would work:
Orion HCCA-D1200
Kicker SX-900.2
Polk PA600.1
Rockford P1000-1BD
When looking at amplifiers and subs, you should ignore "peak" power ratings. There's no standard for peak ratings, so they're useless as a basis for comparison. Always compare amps and subs using the RMS ratings.
