Best car amp frequencies?


2007-09-26 1:29 pm
I'm really wanting to know what the best frequency is for rock music? I have mine on 60hz and on some songs it hits so hard but then when I got to a couple other songs I have listened to before that sounded awesome on my last system didn't sound hard at all. I think I might try and turn it back to 80hz in the morning and see how that sounds now with the 5 volt preouts. I have heard anything from 80hz-120hz on some sites. I think the lower frequencies are used for rap/pop/or R&B. Something that has more bass in it. What do you guys suggest?
Are you sure your amp is compatible with 5V pre-outs? If so, do you have the gain adjusted properly on the amp? Is there a bass boost on the amp? Adjusting the gain, the crossover point, and the boost will definitely affect the output.

I think 60hz is too low. I recommend 80-100, but it is dependent on what the capabilities are of your sub and main speakers as a combination.
The question you are asking if I understand it correctly can not be answered.

I think you are asking of what your LP Hz is a better setting for rock music.
The XO is completely dependant on the speakers, the enclosure resonant frequency and the resonant frequency of the vehicle.

Here is an explanation of how it works and what those numbers mean:

This is cycles per second and can most easily be explained without getting to technical as the wave generated by the speaker, 1 Hz means the speaker will move full in and full out in one second….you can hear this.
10 Hz means it moves 10 times in one second and so on.
You can start to hear bass @ around 35-40Hz.

When you have your XO set at 80Hz this means you will get 80 Hz and below to your subs (this also is where you could look at your crossover slope, a 24db per octave will trim faster than a 12db per will, but nothing you should concern yourself with). A setting of 120 just means that it will start adding more mid bass to the subs because it will send 120 and below to the sub.
Subs that are fast enough (usually smaller subs 8-10”) can handle more mid bass without breaking up. Bigger subs start sounding poppy and clearly don’t sound as good with the higher settings.

So if it is on 40-120 or anything in between means it will still get the same low bass but the differences will be in amount of higher bass sent to the subs only.

I would recommend setting your XO on a setting that sounds good for all types of music and leave it alone. 80 to 100 is for most a good range for most subs between 10-15". If you have 5.25 mids and they are crossed higher consider 100Hz or a bit higher on the subs unless it starts sounding bad, 6.5” mids and 80-90 LP Hz is good.

The XO settings is a balancing act between your subs, mids and tweets.

Good luck.


2007-09-26 1:29 pm
Actually you just answered my question just fine so it can be answered ;) Just like I was thinking, it seems to be usually anywhere up to 120hz.

Well, I'm not complaining about the sound of my system just was wondering on what would be a good setting for rock music as that's all I listen to. The gain is set just fine on the amp and so is the bass boost. I have not yet gotten my second amp as previously discussed but that will only add to the clarity of the highs and more control I have over the higher frequencies going to my 6.5's and 6X9's. I had the car at the audio shop and the guy came out and listened to it about 2 weeks ago and he got me to turn the headunit's frequency to 60hz but he didn't know that below him the amp was set at 80hz. So I have no clue what frequency output that was but that made it hit a lot more than it use to so I left it there until I turned it back to about 60hz on the amp. I'll try to turn the frequency range up a little bit more to 80hz and will see how that sounds in the morning. ;) It was just kind of interesting to hear how some of the bass notes in a bass guitar would sound harder at points than the other. It's just a fact that some songs sound better than others cause it just depends on how they are produced (Like songs produced from the 80's will sound very low output wise compared to songs from the 90's) and how they are played. It's just kind of interesting how some songs sound....
I think my last post was too wordy.

Because you have 6.5 and 6x9s you can cross your subs lower.

You just want to have all gaps filled.

This means (for example only, it will all depend on what speakers you have):

Subs crossed

80Hz and below -


80 low to 1000 high


1000 low to 20,000 +

You can see that one speaker starts off where the other leaves.

If you have your mid set at 80 low to 1000 high and your sub is set to 60 and can see that you are loosing everything between 60 and 80......thats bad.



A setting of 60 is not wrong......

Look at it like this

Lets say you have 2-18" subs, they sound shitty but move lots of air (good).

You could set the 18s to 50-60 low pass or lower and then use some 8" speakers crossed at 50-60 to 200 and could very well feel like the kick drums were punching you in the chest and any sub sonics would suck the air out of you. In fact you could cross the 18s to 40Hz and not even hear them but you would know they were there!

Again it all depends on how you balance one set of speakers to another.
Clipping is a common term describing a distorted waveform caused by driving an amp beyond its design capabilities. And it is the MOST audible form of distortion. Some say the ONLY form of audio distortion audible to the human ear. And there are levels of clipping, from mild to severe. That is why so many experts recommend having amps that are much more powerful than what is actually needed for the task at hand. The extra power that is available allows the user to drive his speakers to their optimum performance without driving his amp to the ragged edge of its capabilities, and thus into distortion.

You see people commonly recommend matching speaker RMS ratings and amp RMS ratings. Even Crutchfield recommends this on their site. That would be fine IF the user NEVER drove their amp into clipping, but almost 100% of us do that in an effort to get the most from our system.

To put it another way, it is much better for SQ and for the equipment if you have a quality amp capable of 500 watts continuous that is being used to produce 300 watts than to have an amp capable of 300 watts continuous that is being maxed out and driven into clipping.

The RMS rating of a speaker is simply a warning of sorts to the user as to how much heat the voice coil can handle continuously. There can be situations of severe clipping that can cause an amp to produce much more than its rated power in the form of heat in the voice coil, which is probably the most common way speakers are damaged. It is also extremely hard on amps.


2007-04-11 9:42 pm
aznboi3644 said:
how many car audio tweets can play from 1000Hz up??

not many. for that you would likely need a large format home audio type tweeter and a very steep crossover slope (at least 24db's) or a wide range speaker like a mid-tweeter. tang band and hi-vi make some decent small wide range speakers that can be used as mid tweeters. i have been thinking about doing this myself but i just don't have the time at the moment.