Contour Enthusiasts Group Archives Forums Modifications Audio 148.7 Decibels at DB Drag ... on the quest for 150.0

Ouch, firing up? bummer. I was wondering how you got them in there. The AC trick is to keep the air dense, colder air is more dense and can yield you more dB (not much, if any but the judges will appreciate the cold car while they place the mics..LOL). Also using your AC may cause your voltage to drop below its normal range after a long period of time. Did you say your is car off while competing?? Then you are loosing voltage right off the bat. When your car is running it should be at 14V or more, with it off is will be about 12.8V. I would recommend you keep the car running. Also another trick is to keep sunlight out of car, Light absorbs sound (seriously) if you have tint then you are already good to go.

I dont think you will be able to port that enclosure you have so lets play with the note you play. I would guess that you may be better off in the 60HZ range, most common is 61-63hz at dB drag events. what ou need to do is play a sweep from 45-65hz at a low volume with a meter in your car at the dash. find the peak frequency (48 may seem the loudest to your ears from all the air it moves but I will bet that you will be louder at a higher note) Once you establish the peak note, play that at full level and you should see a major improvement.

Hey I do a lot of Db Drags my self and one thing I was told to do is rev in engine to about 2000 RPMS that is legal and thats soposta help too.

do your back seats fold down? if not It's not that hard to take them out! you will gain alot more DB. because 4 15" solobarics should hit alot harder! I had a friend with 6 10" MTX 5000's and he hit 147.2 with only one amp

Question is ... where can I go to get a SPL indicator, ie: either an actual db meter mic thingie ... or at least an indication of what mods help and what mods hurt my performance? Just purchased the Bass Mechanics CD. Songs 6-9 go from 70 Hertz down to 40 Hz and are 10 seconds long each for a total of 30 seconds. I think I will use that CD to test out my optimum level of performance. Yes, the backseats do come out, however the box fills up haf way to the top of the trunk, so there is not much room at all in there. Anybody have any ideas on what type of amps I may want to ugrade to if I get rid of my current 2 Rockford Power 800@2's? I hear all this talk about the class D sub amps, but wouldn't know what to purchase. Here is a pic of what the install looks like from the inside without the amp rack, which I unscrew everytime I go to a competition. Forget that, I can't find the pic. damn it! Keep the replies coming guys, I can use all the opinions I can. Thx!

You can get an SPL meter at Radio shack for pretty cheap ~50.00 or so.

Congrats on the score First don't let anyone tell you that the score sucks. For just starting out that is a good score. As far as class D amps go. Everyone will give their own opinion, regardless of which one you choose, class D amps will give you better scores with a stock electrical system.

Analog one = $35 US
Digital one = $60 US

Both only read up to 126dB. Don't know where to buy higher ones.

For testing, a local shop should have an Audio Control meter, obviously your not going to dish out the 2g's for this meter. The radio shack one is ok and you only need it to read low numbers so that you can find your peak without your neighbors killing you. I would ask a local shop for their assistence. Go back to where you got the equipment, if they did the install they should be more than happy to help you out and hopefully havw the audio control mic

Class D amps are good on electrical system and are more efficient, but they produce alot of distortion. You may hear a difference in the sound of you subs, I know I could, the bass was not as crisp and tight (damping factor low I guess) thats just MHO.

Good Luck, let us know how you do. Also if they are using different mics and you score gets lower, dont be discouraged, it happens all the time, as long as both mics read the same then everything is ok. Its when the right lane mic reads louder than the left lane that you complain...LOL

Class D amps haven't reached the SQ level of the best Class A/B amps but they really aren't too far behind, especially in their price range. I doubt it's the damping factor. I used to be a big fan of huge damping factors, but when you really look at what DF is, and how it's affected by the wiring of a system, it is highly over rated. In reality, there is virtually no difference between a amp with a DF of 200 or 500 or a 1000.