posted
you guys just don't know how much that irritates me. is it my measurement system, or my vehicle? or a combination of both? anyone else ever notice that in their vehicles? it is that way for my vehicle and our street a vehicle, but not our ss1-2 vehicle. what are the exact factors that make the difference? barometric pressure? humidity? temperature?
-------------------- Team Livewire Posts: 2199 | From: columbus, ohio | Registered: Mar 2001
| IP: Logged |
quote:Originally posted by Geo-X: you guys just don't know how much that irritates me. is it my measurement system, or my vehicle? or a combination of both? anyone else ever notice that in their vehicles? it is that way for my vehicle and our street a vehicle, but not our ss1-2 vehicle. what are the exact factors that make the difference? barometric pressure? humidity? temperature?
Try setting your clock to a different time.
-------------------- '06 Milan Head: Stock/Sansa e260R (looking for connection) Front: Stock Rear: Stock Sub: None Amp: None
posted
I would say it is a function of temperature. The cool dense night air is probably better for your vehicle than the warm air in the afternoon. If you're in an air conditioned shop, it can still make a difference. I would also assume that this is not with the new termlab as it should read the same either way. One thing to check, try taking measurements on either side of the peak note (like go up and down a couple of Hz) and record them, then do the same at the other time. It may be possible that the slight shift in temperature is changing the tuning of your box/vehicle slightly. I'd say for the summertime comps, you would want to be louder in the heat of the day than at night, but for finals, where its air conditioned, I'd say you'll be just fine.
-------------------- Team Shedluv Team Sweep Team Kicker Team JBL
posted
Do a test at 12pm put some ice in a ziplock bag and put them on your subs and turn the air on in your car until your car become cool, then do a test. I gain by doing this
posted
Mad SPL- you mean his impedance must rise in the A.M.? He is louder during the P.M. so that would be contradicting comments. I don't know if that is the reason or not...hmm. Also, I bet if your bo is in the sun during the day it would heat stuff up inside there really nicely...so keep it in a garage or something and try the ice/air conditioning.
-------------------- 1994 Ford F-250 7.3L Powerstroke Diesel Super Cab Long Bed 33" Mud Terrains Yeah, it's big, and yeah, it's got balls. Posts: 876 | From: Decatur, IN | Registered: Apr 2002
| IP: Logged |
Last week i've been judge with my audiocontrol RTA in a SPL competition. I decided to install an hygrometer and a thermometer near the cars tested to observe the climatic parameter. I decided to do the first pass in am and the second pass in pm.. so all car SPL have been measured 2 times.
In am we got sunshine and with dry ands hot air and for the diner weather condition began to change so we got rain for a short period. In pm, air was charged of humidity and we got no sunshine. I OBSERVED THAT ALL dB RESULT INCREASED BY BETWEEN 0,4 to 1,1dB more !!!
so i conclude that humid air seriously affect dB result !! .. I DON'T KNOW IF IT'S THE MICROPHONE STRUCTURE WHO WAS A AFFECTED BY HUMIDITY, THE TRANSFER FONCTION OF THE SUBs, THE WOOFER FLEXIBLE STRUCTURE OR ALL THOSE, BUT HUMIDITY REALLY AFFECT SCORE!! and temperature too but a bit less.. am: 54% hum 26 degree celsuis pm: 66% hum 22 degree celsuis dB gain (0,4 to 1,1)
Doc
-------------------- Street A "not legal but not outlaw!" Score in my integra: -152.34 dB 51Hz TL sensor -157,1dB 51Hz AC mic
2005-2006 Street A Champion in Quebec province!
CRAZY TESTs: ||||||THE ONLY 6.5" TO SCORE 168.9dB(TL)OUTLAW IN THE WORLD with 6 Watts.|||||| -Crazy 5.25 Bose sub 1.1cu box: 138.0dB TL mic 55Hz with ONLY 100W ! ---------------------------------- www.teamxmax.com Posts: 643 | From: Quebec city | Registered: Mar 2000
| IP: Logged |
quote:Originally posted by asauer: Mad SPL- you mean his impedance must rise in the A.M.? He is louder during the P.M. so that would be contradicting comments. I don't know if that is the reason or not...hmm. Also, I bet if your bo is in the sun during the day it would heat stuff up inside there really nicely...so keep it in a garage or something and try the ice/air conditioning.
This was taken from the topic "Topic: consistantly 1db louder at 12am than at 12pm "
posted
yes, i am 1.0db louder at midnight than at noon. when these tests were done, it was about 82degrees far. and pretty humid around noon. and more humid at midnight, but cooler. about 55degrees far. but condensation was all over everything outside. btw: i have been testing in my shop garage, but with the overhead doors open.
quote:Try setting your clock to a different time.
lol, but i think your on to something. i may try and host a midnight 2x event so i can get cetrified for finals, lol
quote:u can actually tell the difference in 1dB?
unfortunatly, wayne can when he goes to mail out invites for finals.
this whole situation has me trying to invent a way to get around this loss. i'll get it figured out, i always do. i just wanted to see if anyone else noticed this. it makes doing testing during different times of the day a headache.
-------------------- Team Livewire Posts: 2199 | From: columbus, ohio | Registered: Mar 2001
| IP: Logged |
posted
now that you mention it.... last year the loudest score i ever got on 1 shops mic was when it was all overcast, and actually just started to rain.... i didn't change anything in my setup the 4 times that i got mic'd and scores were pretty darn consistant before that day that it rained tho.
also... i've always noticed that scores seem slightly higher on 2nd runs in the evening when it starts to cool down
-------------------- - I don't have a problem with people, its dumb people. So 90% of those who breathe i have trouble with. - If beauty is only skin deep, then ugly goes all the way to the bone Posts: 300 | From: Spokane, WA | Registered: May 2003
| IP: Logged |
posted
from phoenix here i posted a 150 on an audio control mic @ 45 hz
it was 112 degrees and 5% humidity
last weekend i went too oklahoma for the weekend for a relatives funeral
first off i noticwed as i was driving that there was a significant increrase in spl once i got too ardmore
on sunday i miced it again on that same mic cause i took it with me too test some friends rides i tested mine and it was 155 a significant difference to the point at which my ears almost started too hurt
well the temp was 82 degrees and the humidity was at 95%
so in my opinion there is change of spl cause of course more pressure and the air is denser due too the humidity being higher
day before yesterday we done a test in a totally sealed room with one ported 12 h2 test tone @ 45hz 138 then we totally sealed that 12x12x8 foot room off and pressurized it too 5 psi and ran another test tone same power same volume and posted a 142 then pressurized too 10 psi and again another rise in spl
in my opinion and what my partners have seen as that with denser air yields higher spl
a few months ago i coined the question if you pressurize the cabin will you yield a higher spl
most came up with opinions that it was not possible
well in my opinion and from what we have seen it is possible
the higher the pressure the further it is from absolute vacumn that means that theres just that much more of a buffer we can work with
its not how much power you have
sounds travel further in solids than they do in vapor or air due too the fact that they are more dense well you make the air more dense than you of course allow greater efficiency
good luck with this one yall your mechanical engineer is here i dont know all but i doo know some
posted
Hey, goodtunes. What kind of room did you use to get the 5-10 psi pressure and how did you pressurise it? I am skeptical (but curious) so I'd want to prove it myself. Thanks
posted
the room was mad up of sheetrock masonite 2x6s a ton of liquid nails a crapload of drywall screws and te interior was lined with sheet plastic
we used the shop compressor to pressurize the room via a long copper tube that we ran through the door and sealed with a schrader valve on the tip we used 2 pieces if 1/2 inch plexi glas on the door so we could see in we sealed the mic line in we only had one light in there which was on the same stand as the mic there are sveral braces in the room also too keep from blowing apart due too the spl and pressure
we done alot of work it took us a day too build the room at my shop but we done it
and if you decide too build one of these rooms dont stand inside while its being pressurized or is maintaining pressure you will obtain the bends which is a sickness of decompression so be careful
you can check for leaks by useng smoke if you know a smoker buy him a pack of ciggarettes and tell him too knock himself out hheheh
well if there is anything else i can help you with i will be here
quote:Originally posted by Geo-X: you guys just don't know how much that irritates me. is it my measurement system, or my vehicle? or a combination of both? anyone else ever notice that in their vehicles? it is that way for my vehicle and our street a vehicle, but not our ss1-2 vehicle. what are the exact factors that make the difference? barometric pressure? humidity? temperature?
This is what we call in my business "shell temp. correction factor" Your car interior volume changes as the temp out side rises and lowers. I have seen a vessel expand 1/4" over a 8hour period then contract 3/8" when cooled. A car is made of sheet metal and is very heat sensentive. It can work for ya or against ya.
heres it a little formuls that might help.
ambient temp "Outside temp" = amb interior of car temp= it
amb * 7 + it /8= "X"
"X" /.0000124 + 1 = shell temp correction factor
STCF X interior volume= true volume at a specific temp.
Damn I must have stayed awake at work that day.
-------------------- Real men do it on the dash. Others stick it in their port Posts: 346 | From: Houston TX. | Registered: Oct 2002
| IP: Logged |
posted
my highest score of the year came when it was hot and humid and it was my second burp during the 30 seconds hey gene, the midnight show sounds good, make it a fridy as usual
-------------------- TEAM PRODIGY TEAM KICKER http://www.sounddomain.com/id/poundin_firebird 2003 mic quatro champ 2006 meca m5 champ 160 4 d300hc's 2006 meca mr5 champ 155.8 4 d300hc's 2007 splmaxcup champ 2007 bass race 149.9 world champ CHAMP!!!! 2008 year of the rebuild, and rebuild and ...... got loud,but made the biggest mistake of my career at finals : (
![[Mad]](mad.gif)
![[Wink]](wink.gif)
![[Eek!]](eek.gif)
![[Confused]](confused.gif)
![[Frown]](frown.gif)
![[Big Grin]](biggrin.gif)
![[Roll Eyes]](rolleyes.gif)
![[Cool]](cool.gif)
![[Razz]](tongue.gif)
