Sub Wiring/ Power question

[phuphyter]

Please forgive me for my ignorance, but I'm new to car audio. I plan on purchasing a 5-channel amp that puts out 200 rms bridged x2 @ 4ohms (going to my front comps) and 400x1 @ 4ohms(sub channel).

I am thinking of using two RE8's for subs. They're DVCs 4ohm rated at 175 rms each. I'm pretty sure 400w rms is way too much for one RE8 to handle, so I'm guessing I should use two(?) How will they need to be wired? The amp's ratings say nothing about being 2ohm stable, so the subs would have to be wired in such a way that they provide a 4 ohm impedence, right? The DVCs combined with parallel/ series wiring has me confused.

Can they even be used in this setup?

Planning to buy: CDT HD-62s Soundstream VGA800.5 2 RE 8" subwoofers

Thanks for any help

[Rex]

Admittedly, 8's seem small and the pair would most likely be over powered, but I wouldn't loose too much sleep over that. The amp, as well as the HU, should allow for some balancing (gain controls/fader).

The DVC subs can be wired either series then parallel or parallel then series. The net effect would be the same and should be a good load (ohm & wattage) for the pair of subs.

I'll ask why you're using 2 - 8's, is it space related? Are you getting a great deal? Do you like their sound? I'd really suggest going with a 10 or 12. FWIW, A single 12 has more cone surface than 2 - 8's.

[Rex]

Oh, assuming the DVC's are 4 ohm's a piece, then wire them in series so each sub is now an 8 ohm speaker/load, then parallel the 2 subs together to create a 4 ohm load, the amp looks to be able to support that type of load.

I'll make my normal Autotek recommendation as they have a nice 5 channel that can support bridging the right and left to create a 2 channel amp and then the rear supports 2 ohm operation.

I'll think of more and post later, feel free to ask any question.

[phuphyter]

Thanks Rex!!

I didn't know you could wire the pair in series and then parallel like you said. I was pondering that solution, but I thought that if you wired a pair of speakers one way, you had to stick to that same configuration throughout. I stand corrected.

In regards to your question, I'm not really into really low frequency bass. I'm going for sq and tight bass in the "upper frequency" with the ability to produce the lows as well. I know it largely has to do with the enclosure, tuning, and such. I just don't want to put too much emphasis on the lower end of the spectrum. Not really sure if I made any sense there.

Space is also a part of the reason. Its always nice to have some space in the trunk, and they're only 8's. They seem quite versatile too. From what I hear, they can sound like a pair of tens or a twelve.

As for getting a deal on them, according to the sounddomain folks they're $50 each. I'm sure I could afford that, so I didn't really go around comparing prices.

Nothing in my setup is set in stone, except for the CDT's which I'm getting a deal on.

I'll look into the autotek amp too. Which model is it? I can't seem to find it on the website. 5-channel right? Thanks for the recommendation.

[Rex]

If SQ is your goal, I think a single 10 would be your best bet, but you may not be able to find on for the $100-ish you're getting the 2- 8's for.

I think the amp is an SX5750 or something like that.

Your focus should be on the components (CDT's are a good choice) and creating a good front stage. Rear fill shouldn't be to hard to accomplish if you're not looking to shake the roof.

[PoorManQ45]

If SQ is your goal, I think a single 10 would be your best bet, but you may not be able to find on for the $100-ish you're getting the 2- 8's for.

You can get good 10in woofers for ~$100.

Here are some of my recommendations. I have used Cerwin Vegas' alot. They give you great SQ and SPL. Also, they are relatively efficient. Meaning you don't have to have a high output amp.

http://www.adelcom.net/CerwinVegaSSSubs ... VSSubs.htm

If space were not a limitation, I would suggest getting the S-15.4

BTW, Bass frequencies actually start around 100Hz and lower. Most "Subwoofers" start there frequency response at around 50Hz. This means that you lose about a 1/4 of your "bass" frequencies.

Also, 8in drivers work really well when used as a woofer or midrange drivers. If you want a "SubWoofer", you will have to get atleast a 12in driver.

[phuphyter]

I'm kinda leaning more towards the Soundstream amp with the two 8's. Space is a bit of a concern for me (yeah I know the amp is pretty big) and the power is there if I later decide to run larger subs. Besides, I'm not looking for spl right now. They're going into my hatch, so I think they will be loud enough. My bro-in-law has two 10" cm3's sealed in a Montero Sport, and they sound very good, but I think that would be too much for my car/ my goals at the moment.

I could go with one ten for the sq, but I am curious about these 8's. I hear a lot of good things about them from the other online car audio forms (primarily sounddomain) and I figured why not. They're cheap, can handle the power from the amp as long as the gain is properly set, and they require a small enclosure.

I was reading the specs on the re8's and they can hit as low as ~22hz. Not to sound like an a**, but can you expand on what you were referring to when you said that I would be losing 1/4 of my bass frequencies? I just didn't understand due to my limited knowledge on the more technical aspects.

I think the cdt hd-62s will handle the midrange quite well, so that's not too much of a concern to me.

Any more critiques of my potential system are welcome. Thanks for the info guys.

[PoorManQ45]

I was reading the specs on the re8's and they can hit as low as ~22hz. Not to sound like an a**, but can you expand on what you were referring to when you said that I would be losing 1/4 of my bass frequencies? I just didn't understand due to my limited knowledge on the more technical aspects.

On most speakers, including subs, the lowest frequency that they can hit is acheived at a -3Db level. Which means that the sub might be able to hit ~22Hz but it will do so at about half the volume as it would if it were hitting in the 30~40Hz range.

I would be really amazed if that 8in "sub" could actually hit ~22Hz. IIRC, that would require about a 1.5in peak to peak excursion. When an 8in driver has an excursion that long, it must have a really good spider, suspension, and surround for it to not sound like ****.

[phuphyter]

Hahaha sorry I stand corrected. I was going to double check that satement to make sure I didn't sound too ingnorant but I didn't have time. Besides, like I said before, I'm not really into hitting those lows.