4dr vs 2dr blazer

[tapout383 10+ year member]

i mean as long as you guys dont think it will be a whole 3-5+ dbs with 1st gen then i guess it wouldnt be a problem. I run mostly MECA //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif so mic is at headrest

 

[audioholic 5,000+ posts]

Real life > theory

Then clearly the theory needs to be changed. All things in nature can be predicted, assuming we understand the model well enough. An EE student should be more understanding of this. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[audioholic 5,000+ posts]

well im leaving the back seat in for right now...so yes it will be a street app. probably 2 18s...

Well it sounds like a 4-door would be best, although nobody seems quite sure why. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[terra 5,000+ posts]

Then clearly the theory needs to be changed. All things in nature can be predicted, assuming we understand the model well enough. An EE student should be more understanding of this. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

True that

 

[tommyk90 5,000+ posts]

Your description of the readings getting louder when you open the door likely has to do with 1) a bandpass effect occuring, and 2) the mic being placed near the door/window, increasing local pressure due to air displacement at the mic (like placing a mic inside a port almost). Im not saying your conclusions are wrong, just that I think you are attributing a little more voodoo to the situation than is necessary. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
Cheers.

1) Yes it's a bandpass effect, but not every vehicle benefits from it.

2) The door I open is on the opposite side of where the mic is, so that theory is incorrect.

My truck is a bit of an anomaly in that things work differently in my truck than in basically every other vehicle I've seen. Often times even competitors who have been in the game longer than I have are stumped that my truck works the way it does.

Sometimes it's easier to just accept things than it is to try and develop some theory as to why it works. I know I stopped giving up a long time ago. Now I just keep testing different ideas in the hopes that I'll discover something new. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I'm not saying it's voodoo, but people need to contribute more of the score to the car itself, not the equipment. This is pretty evident when guys in europe are doing 159's with 2 10's in a panda in the cargo area, and that same equipment and a WHOLE lot of testing only yields a 156 in a crx.

 

[Lakota 5,000+ posts]

Then clearly the theory needs to be changed. All things in nature can be predicted, assuming we understand the model well enough. An EE student should be more understanding of this. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Okay, let me revise that. Real life is > basic theory. Basic theory, such as air space alone, doesn't work very well with SPL. SPL is very weird. I have seen some things in SPL that are very hard to explain and make no logical sense.

Take for example. I once tuned my box lower (added port length to the external port) and my peak note raised on the Termlab. Most people would say this is impossible.

There is a fine line between theory and SPL. The theory will only get you so far if you ever want to be successful. The guys that are good at SPL spend very little time studying theroy.

 

[audioholic 5,000+ posts]

1) Yes it's a bandpass effect, but not every vehicle benefits from it.
2) The door I open is on the opposite side of where the mic is, so that theory is incorrect.

My truck is a bit of an anomaly in that things work differently in my truck than in basically every other vehicle I've seen. Often times even competitors who have been in the game longer than I have are stumped that my truck works the way it does.

Sometimes it's easier to just accept things than it is to try and develop some theory as to why it works. I know I stopped giving up a long time ago. Now I just keep testing different ideas in the hopes that I'll discover something new. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I'm not saying it's voodoo, but people need to contribute more of the score to the car itself, not the equipment. This is pretty evident when guys in europe are doing 159's with 2 10's in a panda in the cargo area, and that same equipment and a WHOLE lot of testing only yields a 156 in a crx.

I agree the environment plays a bigger role on posdsible scores than does the equipment itself, when comparing reasonably comparable equipment of course.

If the mic is on the opposite side as the open door, my guess would be the main air flow through the vehicle reflects off the passenger side, across the seats, and through the door. This would yield an area of high pressure on the pass side, where its reflected, and thus slightly compressed. This is a perfect example of why cabin space isn't the end-all answer to SPL scores, but I did not mean to imply it was earlier in the thread either.

But thats obviously just a guess why your truck acts like it does, and you've probably already considered it. I dont remember if you have a TL, or have access to one regularly, but if you do it might be a good idea to try and map out the pressure zones in the cabin to locate the air flow path. *shrug*

On the blazers... just seems odd with an otherwise exactly the same interior from the b-pillar forward, and with a wall just behind the front seats, making both interiors for all intents and purposes the same... why would a 4-door be arbitrarily louder. With the wall located behind the rear seat, sure, things will be different. Air velocity inside the cabin would change with a door or window open due to different path lengths, but a wall behind the front seat showing differences just doesn't make sense to me.

edit: In thinking about it, I guess transfer function on the 4-door would still be different even with the walls behind each truck's front seat. But I dont see any other difference between the two setups otherwise.

 

[tapout383 10+ year member]

so which one would u get for street MECA style events? no walls just a regular below window line box wih 2 18s

 

[audioholic 5,000+ posts]

Okay, let me revise that. Real life is > basic theory. Basic theory, such as air space alone, doesn't work very well with SPL. SPL is very weird. I have seen some things in SPL that are very hard to explain and make no logical sense.
Take for example. I once tuned my box lower (added port length to the external port) and my peak note raised on the Termlab. Most people would say this is impossible.

There is a fine line between theory and SPL. The theory will only get you so far if you ever want to be successful. The guys that are good at SPL spend very little time studying theroy.

I dont think anyone has suggested real world testing is not necessary. Current science does not have all the answers. Or more specifically, your ability and/or desire to dig into the details of why your anonmaly occurred are the limiting factor to your understanding of the situation.
I wont even begin to guess why what you say occurred. Obviously it was an outside factor beyond enclosure tuning, a factor we the readers have no knowledge of based on your description alone. Me guessing as to why Tommy's truck acts like it does is enough of a stretch for me as it is, guessing why your situation occurred based on what you've told me would just be silly on my part.

 

[audioholic 5,000+ posts]

BTW let me add that I know you are the expert here on your truck Tommy. I dont presume to know more about it than you do. Just throwing out some ideas.

 

[tommyk90 5,000+ posts]

I agree the environment plays a bigger role on posdsible scores than does the equipment itself, when comparing reasonably comparable equipment of course.
If the mic is on the opposite side as the open door, my guess would be the main air flow through the vehicle reflects off the passenger side, across the seats, and through the door. This would yield an area of high pressure on the pass side, where its reflected, and thus slightly compressed. This is a perfect example of why cabin space isn't the end-all answer to SPL scores, but I did not mean to imply it was earlier in the thread either.

But thats obviously just a guess why your truck acts like it does, and you've probably already considered it. I dont remember if you have a TL, or have access to one regularly, but if you do it might be a good idea to try and map out the pressure zones in the cabin to locate the air flow path. *shrug*

On the blazers... just seems odd with an otherwise exactly the same interior from the b-pillar forward, and with a wall just behind the front seats, making both interiors for all intents and purposes the same... why would a 4-door be arbitrarily louder. With the wall located behind the rear seat, sure, things will be different. Air velocity inside the cabin would change with a door or window open due to different path lengths, but a wall behind the front seat showing differences just doesn't make sense to me.

edit: In thinking about it, I guess transfer function on the 4-door would still be different even with the walls behind each truck's front seat. But I dont see any other difference between the two setups otherwise.

I do have a TL and have tested such things, but not in depth yet. Haven't had the time.

Also, when I was referring to the 4 door being louder, that was strictly in a street style application with the box behind the backseat. Obviously with a wall in both the scores should be identical because of the same front cabin. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Sorry for the misunderstanding.

 

[tommyk90 5,000+ posts]

so which one would u get for street MECA style events? no walls just a regular below window line box wih 2 18s

You won't be able to fit 2 18's under the windowline in a blazer.

Well, you could, but it won't be loud. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

2 15's seems to work the best. Possibly 4 12's.

 

[audioholic 5,000+ posts]

I do have a TL and have tested such things, but not in depth yet. Haven't had the time.
Also, when I was referring to the 4 door being louder, that was strictly in a street style application with the box behind the backseat. Obviously with a wall in both the scores should be identical because of the same front cabin. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Sorry for the misunderstanding.

Gotcha. My bad actually, you did say that earlier, I forgot.

 

[tommyk90 5,000+ posts]

I dont think anyone has suggested real world testing is not necessary. Current science does not have all the answers. Or more specifically, your ability and/or desire to dig into the details of why your anonmaly occurred are the limiting factor to your understanding of the situation.
I wont even begin to guess why what you say occurred. Obviously it was an outside factor beyond enclosure tuning, a factor we the readers have no knowledge of based on your description alone. Me guessing as to why Tommy's truck acts like it does is enough of a stretch for me as it is, guessing why your situation occurred based on what you've told me would just be silly on my part.

BTW let me add that I know you are the expert here on your truck Tommy. I dont presume to know more about it than you do. Just throwing out some ideas.

As ben stated, sometimes its easier to just test and move on rather than try to figure out WHY exactly what happened happened.

Just to throw another example out there, I was testing my single 10" box one day. For fun I cut 2" off the port length, my note stayed exactly the same, and I lost 2.5 dB. I was baffled, but I kept track of that occurence and just moved on. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

No worries about you talking about my truck. I actually like to hear other people's thoughts because it gives me ideas on what else I could test. Having another set of eyes and ears never hurts.

 

[audioholic 5,000+ posts]

With the complex reflections inside the cabin, and the huge differences even relatively small changes make (like window up or down, door open or closed, mic placement, etc), I can fully understand just accepting and moving on. If I ever competed, Id probably be way too anal and never really get anywhere. But the idea of constructing an interior that directs pressure to a specific place (like drivers side head rest, windshield, or kick panel) does intrigue me.