Cuz
Mar 24 2003, 11:48 PM
I'm gonna head down to Epping this saturday to see what kind of a score my gemmi gets. Just wondering as i was reading the rules, if we aren't allowed to be in the car if it exceeds 140db, what do we do? Can u start the track then quickly close the door?
Also, in the rules it says the vehicle can be running, how can we keep it at 2000 rpm without being in the car? And how is this measured?
Another also, even though i have 2 amps, only the one running the subwoofers will count? I can still keep the amp powering my splits connected?
Yet another also, i'm looking at making a test tone cd, as i dont know what frequency my car will play loudest at, what range of frequencies do you suggest i play? My box is tuned to 32hz.
Cuz
Mar 25 2003, 12:10 AM
OMG, i can't believe there is another also! My alternator is out of an ef falcon, it is only 70 amps so i'm still able to be in Stock A? And how many layers of flashtac sound deadening is accepted?
shiny_car
Mar 25 2003, 01:12 AM
QUOTE
Originally posted by SYDWYZ:
if we aren't allowed to be in the car if it exceeds 140db, what do we do? Can u start the track then quickly close the door?
in formal comps, if you were inside the car and it hit 140+dB, you would be automatically disqualified from that round.
the rationale of course being to protect your hearing.
options:
*use remote control
*start the track from inside then hop out immediately and close the door (as you've suggested): this is commonly done when you have no remote control
*use remote HU/podium: that is, the HU be hardwired via RCA/power extensions and used outside the car
QUOTE
Another also, even though i have 2 amps, only the one running the subwoofers will count? I can still keep the amp powering my splits connected?
scrutineering occurs before the commencement of competition. during this assessment by the judges, you will need to demonstrate that only the subamps are connected and operational. all other amps should be disconnected. this is most easily achieved by removing the inbuilt fuses of the splits-amp or removing the remote-trigger wire (and safely insulating it say with tape). if you cannot satisfactorily demonstrate the amp as non-functional, it will be counted in your setup and may put you into another class.
for the sake of your splits, you would want to disconnect it.
QUOTE
i'm looking at making a test tone cd, as i dont know what frequency my car will play loudest at, what range of frequencies do you suggest i play? My box is tuned to 32hz.
if you don't know the best frequency, you could consider playing a sine sweep. that is, a track that plays a range of frequencies starting high and playing lower and lower. such a suitable range would run from say 70Hz down to 30Hz.
interestingly, the termpro setup used by CAAASCA will highlight the frequency that produced the best dB, so you can ask to have your sweep analysed quickly at the completion of your run (and not later as the readout will not be saved on any database).
enjoy the day.
[ March 24, 2003, 23:46: Message edited by: Marc Rushton ]
shiny_car
Mar 25 2003, 01:17 AM
QUOTE
Originally posted by SYDWYZ:
My alternator is out of an ef falcon, it is only 70 amps so i'm still able to be in Stock A? And how many layers of flashtac sound deadening is accepted?
70A is fine to keep you in Stock class in that respect.
maximum 2 layers of self-adhesive SDer are allowed in Stock class. there is a 4kg/m^2 'loading' for the SDer used; note that this limit would allow virtually all commercially available SDer including flashtac, brownbread, G-spot serenity max and most dynamat.
during scrutineering it will be at the judges' discretion as to whether they wish to closely inspect your SDer, so be knowledgable about what you've installed and how to demonstrate it.
Marc
Mar 25 2003, 01:45 AM
if we aren't allowed to be in the car if it exceeds 140db, what do we do? Can u start the track then quickly close the door?
External Head Units / Podiums are permitted in all classes. Otherwise we can count you down yes.
Also, in the rules it says the vehicle can be running, how can we keep it at 2000 rpm without being in the car?
You can't. You CAN run it to 2000RPM, that doesn't mean you have to though:). This is a standard rule used throughout various competition formats around the globe.
Another also, even though i have 2 amps, only the one running the subwoofers will count? I can still keep the amp powering my splits connected?
Correct. Just disconnect the RCA's or pull the fuses.
Yet another also, i'm looking at making a test tone cd, as i dont know what frequency my car will play loudest at, what range of frequencies do you suggest i play? My box is tuned to 32hz.
Our measurement equipment will only record between 20Hz - 80Hz.
I hope this answers your questions. See you down there
hardon
Mar 25 2003, 07:57 AM
Everyone else has pretty much summed it up....
but also....Welcome to CAA!!!!!
I'll be there sat....just look for the crazy one....
Cuz
Mar 26 2003, 02:00 AM
Hey thanks everyone for the great and fast replies! Definatley gonna be heading down!
Shiny you said i should to a sine sweep from 70Hz down to 30Hz. I read somewhere it's not good to play tones below the tuning frequency of your box if it's ported? Is this right or am i dreaming?
Also, what sort of settings should i put everything at? Is it better to have the bass on full on the hu and bass boost all the way up on the amp, or better to send it the best unclipped signal i can?
How long should i make the sine sweep run for? the full 30 seconds,or will the mic pick it up even if it runs through all the frequencies quickly?
Thanks again guys,
Jus
Bodyjar
Mar 25 2003, 05:23 PM
QUOTE
Originally posted by SYDWYZ:
Shiny you said i should to a sine sweep from 70Hz down to 30Hz. I read somewhere it's not good to play tones below the tuning frequency of your box if it's ported? Is this right or am i dreaming?
Also, what sort of settings should i put everything at? Is it better to have the bass on full on the hu and bass boost all the way up on the amp, or better to send it the best unclipped signal i can?
How long should i make the sine sweep run for? the full 30 seconds,or will the mic pick it up even if it runs through all the frequencies quickly?
Thanks again guys,
Jus
Nah, you shouldnt play frequencies below the tuning frequency. If its tuned to 32hz, i'd suggest playing around 40hz. Just do a few burps at maybe 38, 40, 42,45 and see which is loudest.
Put all amp settings and EQ's on flat. Don't boost anything...
Play a test tone for 2-3seconds. To be sure the mic picks up your whole burp, it needs to be at least 2seconds long. But you don't need to play any longer...
shiny_car
Mar 25 2003, 07:43 PM
QUOTE
Originally posted by Bodyjar:
you shouldnt play frequencies below the tuning frequency. If its tuned to 32hz, i'd suggest playing around 40hz. Just do a few burps at maybe 38, 40, 42,45 and see which is loudest.
yeah, sorry, i didn't account for your box's tuning frequency.
BJ's approach is good too. but given you don't have a remote control, you won't have control over what frequencies to play other than making up a disc and playing it over the 30 seconds.
it's true you'd expect the best freq to be around 40~60Hz, so if you can create a sweep only in that region, cool.
yet another approach would be to make up a disc with only select frequencies, say: 60/55/50/45/40. record each for 4 seconds or so and use that.
given it's your first run, you should probably aim to use it as a testing day and try and determine the region of best frequencies to play. you can't expect to hit the nail on the head first time.
QUOTE
Put all amp settings and EQ's on flat. Don't boost anything...
yup. but you ideally will have the gains on the amp setup so your amp produces max power output when you want it.
of course you will need to limit the power if the sub cannot handle it. so the gain and volume setting should be such that you get the max from your setup if you want to get your best score.
if the sub is the limiting factor, then set things so it's just on the edge of distortion.
if the amp is the limiting factor (powerwise), then set the gains (with corresponding volume setting that you can stick with) so the amp is on the verge of clipping (avoiding overpowering your sub).
again, as it's your first outing, don't expect to optimise this straight away. hardcore SPL fans spend lots and lots and lots more time tuning their systems for max dB.
btw, i think it's fair (and sensible), if you're concerned about damaging your equipment, to just have fun and not push things to the ragged edge.
Bodyjar
Mar 26 2003, 10:35 AM
Shiny: You're spending too much time in the SPL forums! You're starting to scare me!
ripped
Mar 26 2003, 12:21 PM
i agree... i think shiny might make his SPL debut sometime.
Cuz
Mar 26 2003, 04:00 PM
Yes i have to admit i was very surprised to get a reply from shiny, must be very scary venturing out from general disucssion
shiny_car
Mar 26 2003, 07:43 PM
muaahhaahaaaa!
Andu
Mar 26 2003, 08:05 PM
quote:
Originally posted by SYDWYZ:
[b]Yes i have to admit i was very surprised to get a reply from shiny, must be very scary venturing out from general disucssion
BlackIce
Mar 27 2003, 11:09 AM
Shiny the SQL man
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