Car Stereos: volts reduction vs. wattage reduction, accurate bass, dvc

Question
QUESTION: Hi Justin,

After much reseach I have decided what to get. I want to get a Kappa One to run a single Type 'r' in a sealed box. The Kappa One runs RMS 800watts @ 2ohms OR 500watts @ 4ohms (1600max). The Type 'r', is a DVC in either 10" or 12" and is available in EITHER Dual 2ohm (1023D & 1223D) OR Dual 4ohm (1043D & 1243D), all four are rated at RMS 600watts (and 1800max).

The 12" type 'r' (both 2ohm & 4ohm) are 23-400Hz freq.response.
The 10" type 'r' (both 2ohm & 4ohm) are 26-200Hz freq.response.
The Kappa One is 20-320Hz freq.response.

Which would be the best type 'r' out of the 4 available and what set-up/configuration would you suggest? I want this for clean, accurate bass.

Later I may add a single 'all-in-one' for deeper, distant (poss. rumble???). I was going to consider the 15" Fli Trap (Active), which is ported and rated at just RMS 400watts (deliberately lower wattage rating than the type 'r'), OR would it be better to run two type 'r', one sealed as per above and one ported, but both running of the Kappa One. Which type 'r's would be better then and how would they be configured with the Kappa One.

Eagerly awaiting your reply and I hope this type of question (and answer) is helpful to others also. I shall positively send thanks and feedback in return. Many thanks in advance.

Best regards,
Simon

ANSWER: Hi Simon,

First off, I wouldn't recommend running a sealed with a ported; they both have very different characteristics, and will mostly just 'muddle' one another if run together.  In my not so humble opinion, there's nothing better than some good clean hard hitting bass without all of the "thtbtbtbtbtbbtbtbtbtbbbt" of rumbly base.  (I don't think that's the official term. ;))

For this amp, which does 800x1@2ohm, I'd get the 4ohm DVC sub, and wire the two coils in parallel, giving you a 2ohm impedance.  This would give you 800w of RMS into the 600w sub (obviously, you wouldn't turn the amp up high enough to blow/burn the speakers.)

If you're serious about buying another sub later on, though, you might want to consider the 2ohm DVC subs wired in series for the time being (which will only give you 500w into a 600w sub, but that's OK), since it makes it easier to upgrade by adding another of the same, and wiring each coil in parallel (giving you 1ohm), and then wiring the two subs in series, giving you an overall circuit of 2ohm.

Justin

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for that Justin and the speed of reply was also very impressive. One thing I forgot to mention was, "Where do 'Farad Caps' come into the equation and what are they really - please forgive my ignorance.

Also, which would give the better sound or are both the same, as per your suggestions above:- Powering the sub with 800RMS @ 2ohm (turned down a bit of course), or powering it with 500RMS @ 4ohm (but turned up a bit perhaps)?
Is running the amp at 4ohm more efficient than at 2ohm?
Important consideration: Most figures are quoted for 14.4v - but as most cars run at ~12v surely it would not actually be 800RMS going to the sub, would it not be nearer 600-650RMS???

Look forward to your excellent reply once again.
Best regards and big thanks so far,
Simon

Answer
Hi Simon,

Caps are literally giant capacitors.  They store power and smooth out the voltage going into the amplifier.

They're particularly useful in situations where your car's charging system can't keep up with the sudden, repeated large power draws provided by your amp usually as a result of a bass hit.  With a capacitor, the draw is smoothed out because the cap will provide the extra needed power, and then draw a more constant amount from the charging system to recharge itself.

You basically need one if you find that the bass hitting is causing your lights to dim/idle to change, etc.

The difference between 500 and 800rms is not going to matter since the kind of volume both of those amounts will put out is higher than any human being should be subjecting their ears to in any car.  Just go with what best fits your future plans.

And you're right about the 14.4V thing.  Most cars while running will sit closer to 14V, but you'll almost never get the full wattage out of an amplifier that it promises.  (Nor through a speaker.)

Justin