Lets talk about

[Lord Baccus 1]

everyone iv spoken to about having an RTA says it is suppose to level the peeks of your system !

and they say it sounds bad, ???

i havent a clue, someone mentioned that they did not come to an event becuase they were Judging by Ear....

Please be sure i have no CLUE about this and am not making a case for ear over Rta ...

all i know is what people have told me...

[johnecon2001 82]

Are you referring to SQ or SPL?

Most SQ judging is done by ear.

[jonbearsmt 919]

well lord. the reason i did not compete thay were judging SPL by ear and thats BS

[Lord Baccus 1]

well lord. the reason i did not compete thay were judging SPL by ear and thats BS

SPL by ear ??? not us !!! we use a Term Lab Pro, iv never seen anyone judge SPL by ear !!! Wow

as for the question i was reffering to SQ being judged by a Meter Vs Ear ???

[JimJ 11]

SQ is judged by ear.

Now, there's a separate event in MECA, and an event in one part of IASCA that's done on the RTA, but both organizations offer competition formats without it.

And the RTA doesn't "level" anything, it just tells you what the current response is...what you do with that depends on what you're looking to get out of it...

[Lord Baccus 1]

SQ is judged by ear.

Now, there's a separate event in MECA, and an event in one part of IASCA that's done on the RTA, but both organizations offer competition formats without it.

And the RTA doesn't "level" anything, it just tells you what the current response is...what you do with that depends on what you're looking to get out of it...

So how is the judging done with the meter ?

what is the Judge looking for ?

[stratusrt01 0]

when I did IASCA years ago, they gave you points based on how flat your response curve was on the RTA. There was an actual set guideline, but it's been too long to remember it now. Then they gave you points based on the subjective listening by the judge where they checked imaging, etc.

It may have changed in the past 15 years, but that's how they used to do it.

[JimJ 11]

So how is the judging done with the meter ?

They have an omnidirectional measurement mic that's on a stand, you put it on the driver's seat so it's relatively at ear height...pink noise is played, which has an equal amount of energy per octave so ideally if the response of the system is flat, the RTA won't register any peaks or valleys. That's usually how RTA scores are graded.

[Lord Baccus 1]

So how is the judging done with the meter ?

They have an omnidirectional measurement mic that's on a stand, you put it on the driver's seat so it's relatively at ear height...pink noise is played, which has an equal amount of energy per octave so ideally if the response of the system is flat, the RTA won't register any peaks or valleys. That's usually how RTA scores are graded.

Wow thats really cool i did not know that.

so having a flat responce is better for lisening ? SQ

[JimJ 11]

Ideally, a flat response indicates that the system itself is imparting no changes to the source recording, at least in FR...so you're hearing it as it is exactly on the source.

Some people love it, some can't stand it and EQ slightly differently

[Lord Baccus 1]

ahhhhhhhhh

this explains why everyone i asked about RTA sad it sounded like Caca even tho the Meter said it was Flat...

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

[JimJ 11]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

[Lord Baccus 1]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

please expand on this !!!

i know how to figure out the Res Freq of a car and tune the boxx accounting for cabin gain,

but this is new to me

Edited April 1, 2008 by Lord Baccus

[Tirefryr 1,742]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

Depends on the tune and your definition of flat though. EBS alignments are know for their "flatness." Of course, eh, screw it, I'm opening a can of worms that's best left sealed[pun].

[audio-neon 34]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

please expand on this !!!

i know how to figure out the Res Freq of a car and tune the boxx accounting for cabin gain,

but this is new to me

To make a long story short, it normally involves tuning lower than resonant frequency so that the "peak" is at the same flat response level as the cabin gains "peak"

Typical spl boxes try to match the peak of the box to mesh with the peak of the car to gain "maximum spl" SQ is all about removing the peaks. Also iirc bandpass boxes are also made to have their lowest output @ the vehicles resonant frequency to remove the peak.

[Lord Baccus 1]

thats what i did to get Jeff his 151.3db

i did the math and came up with 70Hz

taking into account the 36Hz box peeked @ 46Hz i factered that into the math and ported the box @ 60Hz, assumming it would peek out @ 70Hz.

dident account for temprature being 85 degrees..

so it was down his note was 64Hz Sunday

[///M5 2,833]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

please expand on this !!!

i know how to figure out the Res Freq of a car and tune the boxx accounting for cabin gain,

but this is new to me

Perhaps playing with your beloved BBP6 might give you some insight...

I am curious as to what method you use to calculate the resonant frequency of a car.

[creyc 1]

I always hit my cars with big tuning forks to find their resonant frequency!

I too, am curious.

[Lord Baccus 1]

i know when i build a box for music i port it @ the Fs of the cone and get the flatist responce cruve in Bbp6

and the subs readlly preform well in that boxx

Even not taking into account what the vehicle's transfer function does, the flattest response isn't going to come ported...

please expand on this !!!

i know how to figure out the Res Freq of a car and tune the boxx accounting for cabin gain,

but this is new to me

Perhaps playing with your beloved BBP6 might give you some insight...

I am curious as to what method you use to calculate the resonant frequency of a car.

measure from the cone of the sub to where the TL mic is going to be placed /

convert inchs to feet / x4 to get the 1/4 wave or street beat # in Hz / x2 for the Spl # in Hz //

devide that into the speed of sound ( 1131 ) = x

accounting for cabin gain / build & port box to peek @ said #

no accounting for Temp & humidity

Hz # will go down when temp is high

Edited April 2, 2008 by Lord Baccus

[ANeonRider 3]

Can't use math to figure it out... especially in a car...

But, nice try.

[Lord Baccus 1]

Can't use math to figure it out... especially in a car...

But, nice try.

Please do go on ???

feel free to explain why i cant do this ?

as iv tested it and it seems to work...

if i do the math and say i come up with 54Hz !

and then i build the box / port it / meter it amazingly enuff i get 54Hz on a TL mic ???

1x 15" sub doing a 151.7db

temp gos up i go down 2hz !

do you have a better way to do it ?

did the math in lil Jeff car and got a 151.3db with a 12" sub !!!

beating guys with way bigger & more subs subs & amps, not to mention the calcellation

guess i just got lucky ?

and did not have to use a 4th order banpass to do it !

Edited April 2, 2008 by Lord Baccus

[WildSebring 0]

The boxes I've seen Brian build with this formula have worked.

He did it in my car, and said "Hey 70Hz is your peak, we need to tune to 60Hz since your car has a 10Hz increase."

So being that the smart person he is, and the lesser educated I am, I said lets do it, knowing that it is a high #, but I know the man knows what he's doing(SPL Wise).

Went out, but didnt account for 86 degrees on a cloudy supoosedly rain ridden day and do a 151.3 on a single 12" SPLX Soundstream. Everyone was asking , if I had 2 or 3 subs...

Edited April 3, 2008 by WildSebring

[///M5 2,833]

Yep, pretty much Scott nailed it. Your "measurement" method tells you absolutely nothing, if you actually measured though it would...and I mean dB not distance.

[///M5 2,833]

You ask to explain why you can't do that, but for the life of me I can't understand why you think you could do that. If you can let me know that portion I will be glad to explain why not. Perhaps a quick wiki of the term natural frequency will help you. Post away though, we will explain.

[Lord Baccus 1]

You ask to explain why you can't do that, but for the life of me I can't understand why you think you could do that. If you can let me know that portion I will be glad to explain why not. Perhaps a quick wiki of the term natural frequency will help you. Post away though, we will explain.

how are you doing it ?