markow202

Hey guys, never really posted much here before but great forum!

I have a 99 C-class Mercedes. I did a bit of a revamp to the audio system. It had a stock system which needed a bit more bass and added the addition of 6.5" low frequency subwoofers by the optional Bose onto the stock rear deck coupled to an aftermarket amp. The rest is stock head unit, door speakers which sound fine as is. The subs are rated 35-150hz and they DO accomplish these ratings and are enough bass fill for me to go without the traditional sub/trunk route.

Now for the tuning, and this is the same problem I had in previous (same type of car) with an actual trunk sub/amp.

The amp is a MTX Thunder I have right now (Mono). It has GAIN/BASS BOOST/FREQ controls.

How should these controls be PROPERLY set? Ive tried everything. Ive gotten it the way I want but the problem is, some songs have too much bass from the woofers and some songs the woofers barely move.

Currently I have it set to gain = 0 - Bass boost = 3 quarters up and Freq is all the way down.

Before I had the bass boost all the way down, gain a quarter up but the problem with this was the woofers didnt hit on certain frequencys at all, and didnt fill the whole car with bass.

Im stumped....

I just want to avoid fiddling constantly with the bass from song to song.

Please help thanks guys

Mr.DatSubishi

Your freq control is an adjustment of what frequencies you want the sub to play- 80hz will play all frequencies below 80hz until natural rolloff of subs or limit of amp.
-bass boost will effect the output at a centred frequency. Usually around 45hz. I usually tune amps without bass boost.
-gain is the setting which should be matched to the amount of voltage coming through your RCAs or high input signal.
Start with lo pass at 100hz. Bass boost off. Gain down. Turn volume up to where speakers distort on a fairly bass heavy song. Turn volume down to just before distortion. Slowly turn gain up until subs start to distort. Then back down slightly. You should be pretty much good to go If you do add bass boost you may end up in sub distortion land n: and burning voice coils. That's bad. LOL

markow202

Thanks! I got a better idea of what controls does what. I did get an idea of the bass boost having a favourite certain frequency as when a certain song has it you hear it.

This brings me down to my amplifiers control settings....this is what the amp looks like (attached pic). Its set to low-pass frequency bass currently. The dials show no numbers so where is the HZ setting on this thing? If I wanted 80hz for example on the FREQ dial, where would it be? Halfway? It states online that this amp low-pass frequency is 40-200 Hz.

Mr.DatSubishi

Halfway is prob about 80hz. If you want some more kicks you could set it higher. Sub sonic filter should also be on or your gonna torture those little subs if u blast 20hz through em. Are u using high level (speaker) input or low level (RCA) input? Gains in general will probably be set lower if using high level input. Beware of audible distortion. This is what damages speakers. That goes for ALL speakers. It's easier to blow a pair of speakers with 20 watts than 100. Overdriving an amp causes distortion.
Are these subs factory replacement? Are they designed for "infinite baffle" or do they have boxes behind them if they came factory in the car? Also what impedance are these subs? What Impedance is the amp stable to? And how do u have them wired? It could be possible to damage the amp if these subs have low impedance like a lot of Bose car audio stuff does.
This stuff is a lot more complicated than a lot of people think. I blew up a couple amps before I realized you can't just hook up as many subs as u want to it. Oh to be 16 again.

markow202

The subs are infinite baffle and are meant to utilize the trunk as a "box". These are factory made for this particular car and sit in an angled "pod" on the rear deck. They are 2ohm and the amp is 2ohm stable. I have been using this setup for a year now with no issues (so far lol). I am using the high/low converter module due to using a stock deck.

My biggest issue (and it was with every amp/sub setup I ever had) is one song/genre has more/less bass than the next one. House/Dance music will pound too hard and then a jazz track will sound too tinny. Drives me up the wall and this is what im having trouble in tuning. The only way I was able to acheive a balanced sound was to adjust the FREQ of the subs to the point where a bit of voice was coming out of them, but this drags my soundstage to the back and creates too much midrange. Also should I have the bass levels on the headunit in the middle, all the way low or 3 quarters up? I noticed this also effects the type of bass output on the subs.

Mr.DatSubishi

Are the subs 2 ohm each or paralleled to 2 ohms? Your music to bass ratio are directly related to the type of music and frequencies played. House/dance/hip hop etc are gonna be recorded with a lot more bass than jazz/classical/50's swing dance etc. Not much you can do but have huge power and subs with a remote bass ****. Turn it way up for jazz and not so much during bassier music. Id leave the bass setting at med, or flat. Adjusting your bass on the deck will probably push too much bass to your front speakers and overdrive your amp and you may end up into distortion and speaker damage. Factory stuff sucks in general. It's designed to give a little extra sound vs. Reg. Factory stuff but compromises performance for cost.

markow202

Ok gotcha. The subs are 2 ohm each (individually) drivers. I will play around with it a bit more but otherwise I guess thats how it is

Bumpin Balt

If you want to retain the bulk of your stock stereo system, you should look into a JL Audio "Cleansweep" setup. If you want more "full" sounding bass, I would add a single 8" or 10" sub that's rated at ~500-600rms and a suitable amp. With 6.5's, your system is going to be lacking on the low end.

fresh1

iTrader: (2)

Some songs don't have as much bass as others.

markow202

Thanks for the tips guys! The 6.5" subs although look a little anemic, produce low bass notes.

Do all of you experience the problem of one song booming more than the next?

This is when it would be nice to have DSP or an active EQ such as the full blown premium audio system in this car would have. The EQ in the amp is active and adjusts based on volume and material being played.