stevej88na

Here's what the potential recording standards:

Sound Recording Standards

1. No-Load: Mic centered 5' behind the RX-7, at head height. With engine fully warmed, idle for a few seconds, then rev to 2k and back, rev to 4k and back, and finally rev to 6k and back.
2. Under Load: 2nd gear to redline buzzer, with the mic positioned where the driver's or passenger's head would be. This is under load (i.e. merging onto the freeway) with the driver's window and sunroof open.

That should probably give people a good feeling for the exhaust sound. Sound about right Valkyrie? I'll redo my RB idle at night when there's not so much traffic or wind, but I'd like the third time to be my last time if possible - does the new standards list above get the community's blessing?

Valkyrie

Sounds pretty good to me.

For the record, starting the car gives a good benchmark for noise level, since I figure most RX-7's sound about the same when cranking, and the difference between this cranking noise and the sound it makes when it fires up gives you a good idea of just how loud it is.

Or at least a better one than honking the horn

An RX-7 with a straightpipe and big mufflers will sound like you just awakened a beast, where as a stock car will only be slightly louder than the engine turning over.

There should be *some* leeway in the way people want to rev their engines, though... if only for artistic expression :p

As long as they keep the actual RPMs within the general area...

stevej88na

Good suggestion about cranking, I'll put that in there. So here are the (probably final) standards for recording exhaust sound:

Sound Recording Standards

1. No-Load: Mic centered 5' behind the RX-7, at head height. With engine fully warmed, shut the car off. Then record cranking and and idle for a few seconds, then rev to 2k and back, rev to 4k and back, and finally rev to 6k and back.
2. Under Load: 2nd gear to redline buzzer, with the mic positioned where the driver's or passenger's head would be. This is under load (i.e. merging onto the freeway) with the driver's window and sunroof open.

It's good we ironed out the standards before others posted clips.

Sideways7

iTrader: (7)

Well, I dug up my video, but I'm not sure how useful it is for comparison. I have a LARGE streetport and ported exhaust, so it changes the exhaust tone.
Also, my car sounds pretty different on starting. It has some crazy strong pulses when starting. Anyway, I'm trying to get the damn video edited. For some reason, windows movie maker doesn't recognize the video portion of the file, and the whole think is almost 400 megs (10 minute video). I will see if I can just record the stuff I need and post links.

stevej88na

Hmm interesting, sounds like we'll need to specify which clips came from what type of port job too. Looking forward to hearing your streetport!

Sideways7

iTrader: (7)

I copied off a small clip that has a 30-80 acceleration from the passenger seat, plus idle and redlining in neutral. I just threw it up on streetfire for the time being, since its getting kinda late here. I'll see if I can find a better clip tomorrow, and get it uploaded to the site.
Here's the link to the vid: http://videos.streetfire.net/video/6...58001f0db8.htm
Last I checked its still optimizing, so you might need to give it a bit.
Edit: I'm going to be dropping in a 95k miles s5 engine to my car to get it running while I save for a rebuild, so assuming it still runs, I should have a vid of this exhaust on a stock engine in a few weeks.

Sideways7

iTrader: (7)

Ok, the video is working now. I've got some more clips, but I think I had a small exhaust leak at the time. I'll post up some of them later. It sounds pretty mean with that exhaust leak.

stevej88na

That sounds clean and mean -- I like it. We can just post a link to that video on the page, or if you/me extract the audio, I can host it where my clips are now. Is streetfire reliable, like do the videos stay there for years? That might be a good second option, because videos help quite a bit for getting a feeling for the system.

Whizbang

sometime soon you might have 3" straight pipe

Sideways7

iTrader: (7)

I honestly have no idea how long stuff stays on streetfire. I can try to extract the audio, but I'm not quite sure how to do it. The whole file is only 6 or 7 megs, so I could email it to you and you could do it if you want. We can work it out in PMs if you want.
And yeah, I love how that exhaust sounds. The only thing I didn't like is that it is pretty damn loud. It gets pretty old on long drives. Just for reference, the redline buzzer still works, but you can't hear it at all over the exhaust.
You should have heard it when I had nothing but the stock exhaust manifold for a few days. It sounded so awesome at idle, but it would cause hearing damage at full throttle. I only floored it once and my ears were ringing for several minutes. I could set off car alarms from several blocks away.

ericgrau

iTrader: (1)

dB meter 10' from tail pipe. That should remove volume worries. Just post the dB alongside the sound clip.

Sideways7

iTrader: (7)

Yeah, but how many people actually have a dB meter?

JSmith0101

iTrader: (6)

http://www.youtube.com/watch?v=bNXejcb_kp4

This is all I can get right now, later on I'll do it right, but this is an idea. Don't worry, it will get better.

Watch for teh fire.

stevej88na

Not shabby, wotnartd! That's a good sized fire ball. I've got Sideways7's exhaust photo and clips up; that idle just screams ported. Wotnartd, if you can get me a photo, I can link to that youtube page for the sound/video, and then at some point just take a video under load. Or send them to me and I can extract the audio (I'll PM you the address).

JSmith0101

iTrader: (6)

I know it sounds ported on the idle, but as far as I know, the block is copmletely stock, except of course for the header.

Sideways7

iTrader: (7)

Yep, nice fireball. I had bit of fire on my revs, but you can't see it too well because its daytime.

JSmith0101

iTrader: (6)

A bit more info on my exhaust, volume-wise, it scares puppies, big four weheeler off raod trucking guys, and my roommate says it's really loud, but not ricey at all... and he calls me "el rice-o."

stevej88na

Updated with wornartd's system! Anyone else have clips and photos to add? Also, wotnartd, feel free to log in and update the description if you like.

http://howto.globalvicinity.com/gv_w...i=66&co=1&vi=1

Sideways7

iTrader: (7)

I finally got the spare motor in, but its not running right so I don't think I'm gonna be able to get a clip of my exhaust on a stock block. I'm still hoping I can save the motor, but I'm rapidly losing hope.

Sgt. Pepper

My Racing Beat full collected exhaust is up on the website so if you want to know what it sounds like go check it out. You can compare between the True Duels and collected exhaust.

stevej88na

I've got the GV pages set to give anyone registered a personal page (unlike all other pages, only the owner can modify it). I'd like to get the cars associated with their owners, so we can post more info about the car specifics. For an objective exhaust comparison we need to know various engine modifications (porting), and everything about the exhaust system. So, if you've got your exhaust info on that page, link it to your member page. For me, I edited the exhaust options and added this to my RB duals and A'PEXi GT sections:

[[member: stevej88na]]

You just replace my name with yours (duh).

melicha8

iTrader: (1)

This may not be up to the testing standards but here is a little vid I posted a while ago.
http://www.youtube.com/watch?v=JVXzIFzovBk
Don't gimme **** about the squeeking door it's fixed. This is a non turbo with a Bonez superflow and Racing Beat Dual Catback.

stevej88na

You picked your camera up pretty quickly after revving, you are like lightning! Though it's not up to standards, it's still useful, and I'll link to it. In some ways, the more sound clips to compare, the better, but in others, we need to get as close to the standards as possible to be useful! Got any photos of the car from the back? Also, is it stock everything except cat and cat-back?

I've got a new preferred method of sending me photos to post. Only "editors" and up can post photos to random pages in an effort to not host ****, but anyone can post photos to their own homepage, and I can snap up the photo link from there. That kills two birds with one stone - we get a good photo of your car's exhaust installation up, and we get a link to your page where we can see details of your car.

Edit: for convenience, here's the link again:
http://howto.globalvicinity.com/gv_w...i=66&co=1&vi=1

jonesfromindia

make it mono L and mono R, so it sounds stereo

stevej88na

pff I'd have to get the phase exact, which isn't happening!