Bass blockers, etc..

[slinker]

1 - My friend said there is a product known as "bass blockers" which you use for your regular speakers to prevent them from trying to handle to much bass. Is this what i will need if i want to be able to raise my subs bass level from the HU without risking blowing out my door speakers?

2 - Is rewiring your car a good idea? That is, will there be a sound difference if i replace the stock audio wires running to my speakers? Would this be difficult to do? My cars from 1989 so the wires are old, i just dont know if age really affects their ability to carry sound ...

3- I saw an ad in Stuff magazine for some 4" subs that you can mount in your door or wherever i guess that apparently put out bass equivalent to some 10" or 12"s. anyone heard of these? opinions? It would be nice to not have to waste the space for a box and sub in my car ...

4 - Do amps need alot of airflow or can they be hooked up in a pretty tight spot like the enclosed area under the rear seats of my cherokee?

[bmwm3guy]

1- Bass Blockers, or better know as crossovers, channel the frequencies of audio going through the wires, therefore you can channel the bass to your subs, mid to your mids, and high freq. to your tweeters.

2- Unless you have high performance speakers, the stock wiring should be fine unless you can here distortion, but that would most likely be the speakers before the wiring.

3-Junk, you will never replace 10-12" subs with 4" ones. They may be good bass, but nothing compared to 10s, 12s, 15s, or 18s.

4-Most of the time amps require good air circulation because the transformation of power emits TONS of heat. If you have a 800Watt amp running at 50 watts of power you wil have no problem, but otherwiose ensure the amp gets enough air so that is does not ofver heat. Under the seats of your cherokee shoudl be fine, but I dont know te clearance the amp gets so it really depends. Try installing a small fan or re-direct an air vent.

Hope that made sense.

[Haibane]

Originally Posted by bmwm3guy

1- Bass Blockers, or better know as crossovers, channel the frequencies of audio going through the wires, therefore you can channel the bass to your subs, mid to your mids, and high freq. to your tweeters.

2- Unless you have high performance speakers, the stock wiring should be fine unless you can here distortion, but that would most likely be the speakers before the wiring.

slight edit to 1: The crossover is used to cut out, lows, highs, mids etc. from the response of a speaker. Channel frequencies is really not true.(no offense) Channels are the different sources a speaker connects to on an amp or headunit. Crossovers limit channels in order to increase performance in certain areas.

As for #2, wrong. Stock wires only transfer about 10watts RMS, since they are so small, if you are using an aftermarket headunit you will want larger wires. I suggest 10-8 guage wires. I know that sounds large, but in the long run you will see the need.

[bmwm3guy]

mehhh.. close enough. lol

ok so channel wasnt the word but I was trying to illustrate the idea.. anyways...

[sr20de4evr]

10-8ga for speaker wires??????

maybe for 2000rms going to a sub 20 feet away, for normal speakers anything larger than 16ga is overkill

[GSteg]

for speaker wires, i tend to use 12-14 gauge. imagine 8 gauge. lol.

by the way, those bass blockers are really only a 6db octave capacitor lined up with the speaker. You can buy your own capacitor and pick out your own frequency cut-off. Not to mention they aren't that expensive and for the price of a single bass blocker, you can make a 12 db octave slope xover.

but if you just want a slap on stuff and don't really care about how it sounds, the bass blocker is good enougn.

[Haibane]

ok, so I slightly exageratted the speaker wire size. i forget what sizes are what exactly lol

[PaulD]

bass blockers are just a capacitor .... they are a high pass filter - meaning they pass all the frequencies above a certain point.

[burly]

One thing to remember if you buy your own is that you will want a non-polar or bipolar radial capacitor in order to wire it in series with the + lead of your speaker. Also, get one with a quality plate and electrolyte material and rated at at least 50Volts, preferably 100V. I use a pair of them on my front 4x6 component plates and it really helps free up the speakers to play frequencies that are in their dynamic range, instead of being distorted and overextended trying to play something below their range.

As far as speaker wire, I'm not sure I completely agree with the numbers being thrown around. Yes, a slightly lower AWG will probably improve your sound quality, but that is more due to the better RF insulation of the aftermarket wire than the OEM wire. Stranded 18AWG speaker wire is good for about 6-8amps at midband AC frequencies (~10amps for DC transmission or 1phase AC), and that is a rather conservative estimate. The resistance per 1000 feet is about 7 ohms, so in the 10-20foot runs in the car, you are looking at about 0.007ohms, negligible. With a 50W/ch amplifier, using ohms law a thats 2.5amps @ 20V w/ 8ohm load or 3.54amps @ 14.1V w/ 4ohm load. This is well within the capabilities of the wire and its given length. Granted, you wouldnt want to use it on your subs, but from a headunit to a speaker, 18AWG is sufficient with 16AWG being on the audio enthusiast side. Coming from a seperate standalone amplifier, it depends on the output wattage and the given length of the cable. The big thing in speaker cable, especially when running it in bundles of other wires in the car, looping and bending it around (introducing induction losses) is to go about 1 step lower in AWG (as in, 1 step larger wire) than the AWG rated for your power use, and blow the rest of your money on GOOD wires that have GOOD shielding. Power is only useful if it is clean.

[PaulD]

LOL .... RF sheilding only works on ..... RF frequencies. Sheilding a cable for frequencies below like 500KHz is pointless in a car

NOTE: 500 KHz = 500,000 Hz
audio frequencies = 20 Hz to 20,000 Hz

[burly]

Talk to 3 different EEs and youll get three different ranges for RF frequencies. It really depends on what field you are working in. If you would like a more generic term, then substitute EMI for RF above.

As far as the usefulness of better insulation and shielding at a given frequency, that totally depends on the shielding material and how well the shielding is grounded. However, avoiding inductive losses and EMI from other close by or bundled wires - such as antenna coax (running anywhere from 535kHZ to 108MHz) , your nearby cellphone (900Mhz - 2GHz or more) or handheld walkie talkie, CD changer serial bus, etc. - is delegated by insulation and shielding.

RFI and EMI are real forces to be dealt with, especially if you are comparing amplifiers with <0.1% THD and S/N ratios > 100dB. If you find variances in these extreme values to be impactful, then properly insulated and shielded wire will make a noticeable difference as well.

In other words, if you (collectively, not personally) are going to breakdown amplifiers' THD, S/N ratio, and wires' power rating to such a degree of scrutiny, then EMI and RFI are important considerations. No LOL required.