My day at the DB sound off

[Pte Socks]

Well I finally decided to enter a show and see how well my system did. All in all.. I was pretty happy with my results. Now the problem with the DB soundoff was the DB readings. The problem was that they mounted all mic's on either the driver or passenger seat. Unfortunatly, you werent allowed to put them on or near the front windshield this resulted in a loss of approximatly 10-11 DB's. This loss was calculated by those that had entered many other sound shows and they know what their system runs at. Also the guys who hosted this event told us to expect a 10-11 DB drop from what your system is. Anyways, I had two runs with my car. The results are this.
First run.
- 127.7 DB playing The Crystal Method, Tweekend, song 1
Second run.
- 130.4 DB playing a DB drag race comp cd.

So if you calculate correctly, my system runs at just over 140 DB. Not bad considering my setup which is at the bottom

[nineteen88ga]

Nice job!

BTW how do you like your M500? What do you think of how you have to set them up? How do you have yours adjusted? I still never really tinkered with mine, I want to pick up an AUX-4280 so I can adjust/view the functions from the interior of my car.

[Pte Socks]

well personally i love the fact that it does not heat up at all and is completely digital so i can have it right against the back of my seats. The setup on them is a little bit of a ***** though. My subs are run in parallel at 1.5 omhs and the amp is designed for 2 ohm loads so sometimes on some songs my amp will overload with current and shut down.. a safety device in it. As for the setup. Well im not exactly sure of my exact setup for my amp. There is a lot of stuff you can adjust and it would take a long time to explain. My best advice.. Do what i did. I just popped in a cd that i listen to when i really want people to hear my system. Put it on the song that plays the best ( ie the song that gets you the most bass) then you just adjust your amp so that that song sounds the loudest. I would recommend you look at your owners manual and see how to setup your amp. then just follow the instructions and just use your ears as to what sounds the best. Thats how i setup my amp and it seems to run quite well. All in all.. im very happy with the amp and my setup

[nineteen88ga]

yeah I know what you mean. I have mine set up for SQ but just wondered if it was jet me who thought set up was a pain! lol

I'm running mine at 2 ohms (with 2 dual 4 ohm Type R 12's) and It's like ice when its on. My 4 channel heats up more. Compared to my old amps (which were both ClassAB amps) they V12's can't even compare.

The way I have mine mounted, it's kind of a pain to get at, so that's basically the reason I want the 4280, plus having the amp temp and voltage in the vehivles cabin make a little more sense. Its kind of hard to monitor the amp if its in your trunk and yoru in the Driver seat. lol

[Pte Socks]

that setup you have is an excellent setup man.. those things were like designed for each other and i bet you hit in the high 130's all the time with a decent cd. Actually.. the setup i have is that i have my rear 70% seat folded down so i can see my amp and i can easily adjust it. though i love having it right up against my seats so i can still have acess to a lot of my trunk and thats why i like the digital aspect

[nineteen88ga]

May 10th I did my first sound off of the year. It was put on by S.L.A.P., so it wasn't a backyard organiztion running it. I knew it had a lot more bass than my single 12w0 from my last setup, but I knew it wasn't an spl machine, and since I was aiming more toward SQ I just entered the dBQ comp. The judges said my imaging was dead on, but since I was still working on a few little bits of the trunk I got 2nd place to a 300ZX from Tweeter.

For my spl run I hit a little over 130 dB. A little disapointing since my W0 hit 133.3 once last summer, but I guess since that was with the M500 set right out of the box (no adjustments made to it at all) it wasn't too shabby. I'd like to get as close to 140 as I can, but even the S.L.A.P. guys said that a typical SQ vechicle pushes around 130 or so.

[car audio dave]

hey unreloaded...to let you know...the way you dod it in that comp was normal. some leagues CHEAT by letting you put the mic wherever you want (ie: by the windshield). your reading is accurate if you look at what the good leagues do. i hit 143 with the tripod on my seat and mic where my ears would be. thats exactly how any reputable comp does it. otherwise the numbers are rediculously loud.

130 still is a great score. i couldnt get that in my new system.

[sound_xtreme]

i agree. unless they used the new term pro mics. Those are meant to be mounted on the windshield and are already about 6 dB down(mounted on the windshield with suction cups). I was told this by the term pro manager at the Cruisefest Nationals dB Drag contest.

[Pte Socks]

Well basically im just going off what these other guys were saying.. the ones who had been in many other competitions before this. They all account that this mic was 10-11 DB's off what their system runs at. I dont know if it was exactly the position of the mic or not what was causing the 10 db drop that they were talking about. I do know that they were having problems with the mic and the readings it was putting out so that could perhaps explain the discrepency. Well dave.. if you know a lot about systems ill give you an example. One guy has a JL 12w7 in a bandpass box with a JL 1000w amp and he was running 137.3 DB if this is what that system is rated at.. then i guess the results are accurate. so hopefully this helps.

[Pte Socks]

something is amiss.. 1988GA claims that his single w0 runs at 133 DB.. now that is just hard to explain if im only running at 130.4 with my 2 12w6's

[Pte Socks]

my mistake again.. the guy was running the H.O wedge for his 12w7..

[car audio dave]

i hope my post didnt offend you, i wasnt trying to put you or your system down.

that said...i always hear at shows "oh this mic must be off" and "i usually hit 10 dBs higher". its simialr to when you go to a friends house right adfter they clean up, and they say "excuse the mess".

as far as the w7 system goes...every car is different. if i listened to it then i could give you a judgement. weve done a 10w7 in a vehicle and it had no volume, and weve done it in a similar car and it was really loud.

same goes for the system with a w0. along with the install that varies also how its measured varies. like i said before.. a few leagues measure at optimal points, others measure the standard place...the seat.

[Pte Socks]

hehe no.. it didnt offend me.. im just trying to save some pride. I have heard from so many guys that my system was a 140 system just by them listening to it with a comp cd and when i hit only 130's at this show i felt a little ashamed. But then i heard everyone talking about how the setup was going to be running at 10-11 Db's lower than what the mic was reading because of some reasons... i was so happy and it made my day. meh.. all i know is that my car shakes and rattles like no tomorrow when i have the bass up high.. im proud of my baby.. i just wish i knew if it was a true 130 or 140 DB car... 140 sounds so much better :). The setup for this audio even was so that the mic was in either the passenger or driver seat. I decided for the passenger and just went with it.. i wish i knew if my car was 130 or 140. Anywho.. i definatly have to buy a comp cd.. its was like the young, beautiful, virgin system days when my stereo would make my entire body itch and my ears feel like they are gonna explode... sadly all i get now is a full body massage and no itchy nose.. sniff.. i miss those days.. :(

[JAFO2RHh]

Originally posted by car audio dave
hey unreloaded...to let you know...the way you dod it in that comp was normal. some leagues CHEAT by letting you put the mic wherever you want (ie: by the windshield). your reading is accurate if you look at what the good leagues do. i hit 143 with the tripod on my seat and mic where my ears would be. thats exactly how any reputable comp does it. otherwise the numbers are rediculously loud.

130 still is a great score. i couldnt get that in my new system.

Dave, which sanctioned body let you put the mic there? And was that for the spl portion of a SQ comp or an SPL comp?

[car audio dave]

i believe for dB drag you put the tripod on the seat, and for USAC you put it where you want. im not sure about the IASCA dB league, but ill get its in the seat as well.

unrealoaded, i didnt mean to rain on your parade. honestly, what does a number mean? if you like then thats all that matters. my system couldnt be very loud right now, and i always hear that, its always "what, its a $10k system and its not all that loud!" but i am happy with it and thats all that matters.

[nineteen88ga]

I never really thought about mic placement as a factor of dB.

My very first reading was in a dB Drag 127. My 2nd, reading was in an IASCA SQ comp, I hit 122, and my 3rd was at a local shops Sound Off that was run by Rockford Fosgate, 133.3dB. For my new set up, I hit the 130 in a S.L.A.P. show.

The one run by RF (the local show) the mic was placed on a stand that sat on the floor or on the seat. The rest were all windshield mounted mics, but I forget about the dB Drag.

But I like what you said Dave, about it just being a number. who cares how high your SPL is as long as your happy with it.

[car audio dave]

yeai was up against a guy with an intrepid once. they put his mic on the seat liek i did when i hit 143, and he got 120. he was so upset they decided that just for kicks theyd stick the mic in his port. he hit 150! i still got the trophy.

[Pte Socks]

What setup did you use to hit your 143 dave? im guessing its your 2 JL 12w6v2's but what amp are you running? if your running that system with let say a 1000w rms amp id be very surprised to see you be able to beat me by 13 db's which is a huge difference. Thats why im slightly skeptical about a lot of things.. and i dont really know what to believe.. As for sound and how happy i am with my system.. Im very proud of it and i dont think i would want a much more powerful system.. I dont have to be told by anyone that im losing some hearing because of my system because I know I am/will be. anything over 110 DB's starts doing ear damage and I know I hit well over that. I just wish i knew what my system hits at.. so I know for future reference and comparison to other systems. theres a huge difference between a 130 system and a 140 system and i would like be able to tell which is which by just listening to it.

[car audio dave]

in my 143 dB system actually i didnt have the JLs. i had 2 12" TREO street series subs. and i had the MTX thunder 2300x. i tested it at 500 watts to each sub.

a difference of 6 dBs is huge at that level, and honestly, even 3 dBs is audible. the problem is...in different environments, different dBs will sound louder or quieter.

[sound_xtreme]

dB drag is supposed to use the new mics that came out this year which mount on the windshield using suction cups.

[Pte Socks]

yea.. thats what ive been told extreme.. the problem is.. this was a show put on by a retail outlet and though it was called a DB drag race.. in reality, it was not.. it was more like a bunch of guys with system and they put mics on your seats. Besides that.. it was up to you.. so some guys in trucks would push their seats foreward so they could get more airflow. Them some guys pushed their seats way up as far as they could to ge it closer to the windshield.

[andy]

Although not terribly familiar with sound offs, I can perhaps add something worthwhile.

When a soundwave reaches a boundary, in this case the windscreen, the wave actually doubles. You have the incident or the wave hitting the screen and the reflected. So, in accurate conditions (not found in a car) it would lead to +6dB of SPL.

I would imagine this is why a tripod on a seat is looked at to be more accurate as you don't drive around with your head against the windshield.

Apologies for the different terminologies, not native US!

Andy