First Audio Build (Need Math Help!)

[TOOSTUBBORN2FAIL]

Stugray, I had a feeling we were both communicating the same thing in different ways.

Your point about spectrogram analysis is why I highly recommend running active in car audio environments. It allows you to keep all speakers running in their pistonic range, and removes frequencies that they can not deal with. That was a big reason I could run the power I ran in my last system without frying things, I kept all speakers crossed above their resonant frequency, and below the point where they began beaming.


Mc.ac, I would argue all of this is important, but perhaps deserves it's own thread.

[Shankenstein]

Originally Posted by Mr.ac

yep and meh. Still kind of point less (in my opinion)

If you want a great and one that I personally use test and tune cd look for Bass Mechanix Sonic Overload.
it has everything you need to blow shit up, or tune it just right.
from 1hz to 200hz Pink noise, shine waves, and just old fashion bass farts.

Although I'm not a professional audio engineer... I wanted to share my system tuning routine, and many learn about everyone else's methods.

1) Overally level and coarse EQing. I like songs that build up, with most of the content on the center channel.
Rufus Wainwright - Across the Universe
[ame="https://www.youtube.com/watch?v=cAe1lVDbLf0"]Rufus Wainwright - Across The Universe - YouTube[/ame]


2) Tackling the top and bottom octaves. I like songs with extreme frequency content, but sparsely distributed instruments.
Owl City - Meteor Shower (the FLAC version doesn't have all that artifacting in the echoes):
[ame="https://www.youtube.com/watch?v=8SMcixGyI5c"]Owl City - Meteor Shower (Extended Edit) - YouTube[/ame]


3) Setting crossover points, overlaps, relative levels, and time-alignment. This is the bulk of the work, since you're making things vocals realistic and instruments recognizable.

Artists like:
- Dave Matthews Band / Blues Traveler / Steely Dan
- Sarah McLachlan / Etta James
- Bill Withers / Ray Charles / Hugh Laurie
- Duffy / Adele / Amy Winehouse

4) Sanity checks with tones and noise. An RTA is indispensable for a newbie, like me. Some people can do it by-ear.

[MidnightMonkey]

Ok. So I think I'm going to go with this Alpine

http://www.crutchfield.com/p_500PDXF...ne-PDX-F4.html

Any thoughts?

[Shankenstein]

Originally Posted by MidnightMonkey

Ok. So I think I'm going to go with this Alpine

http://www.crutchfield.com/p_500PDXF...ne-PDX-F4.html

Any thoughts?

Initially (10 years ago), I was pretty skeptical of the Alpine's PDX series. Impossibly small footprint and Class D architecture. Similar to JL Audio's amps... but they didn't cost as much.

I assumed (wrongly) that it was a conventional Class D that couldn't handle high frequencies well... and it was a mini amp that would overheat and die if there wasn't great protection circuitry.

That's just not true. They sounded good, had plenty of convenience features, and their owners rave about them. From what I've read, they've made some big improvements over the years too.

I'm betting that Alpine's OEM division helped develop the critical mass of R&D budget to make a better chip amp. Their amps from the 90's - 00's were chunky (and not too different from their aftermarket lines). With a chip amp, you can reduce mass, component count, footprint, and heat dissipation... which lets you pass the same customer validation testing with much better profit margins.

[stevesnj]

using +/- 1ohm is fine...I had the same issue with my truck. Infinity uses 3ohm on their studio series and 4ohm is for the head unit. Talked to Crutchfield and they say it's not a big deal, it does depend on tuning your amp and HU correct. I tuned my amp with a multimeter and i never get any clipping or distortion when at full. Only went to full a few times but otherwise just tune it correct. It's worth the effort and time for the money invested.

[TOOSTUBBORN2FAIL]

That is a great amp. There is a tiny turn on pop with it, some people can hear it, some cant. In a moving car you cant. But, aside from that, which I consider a non-issue with how low it is, it's a great amp.

The extreme class sound quality champion last year in California used them.

[Mr.ac]

Originally Posted by MidnightMonkey

Ok. So I think I'm going to go with this Alpine

http://www.crutchfield.com/p_500PDXF...ne-PDX-F4.html

Any thoughts?

It's a good amp.

[justatroll]

FYI:


Largest speaker stack ever configured in North America. This stack is capable of 1,500,000 watts (1.5 Mega Watts):











We were able to reach 145 decibels....


I would love to take one of those loud ass guys with the obnoxious car stereo systems and put their car in that circle.

[TOOSTUBBORN2FAIL]

Is that full range pink noise? If so, that is impressive.

Car audio guys get into the 150-160 range all the time, and some have even gotten past 180, but they are all one note wonders that can only do it for a couple second bursts.

[justatroll]

Originally Posted by TOOSTUBBORN2FAIL

Is that full range pink noise? If so, that is impressive.

Car audio guys get into the 150-160 range all the time, and some have even gotten past 180, but they are all one note wonders that can only do it for a couple second bursts.

I am not positive what they use to drive the system as far as white/pink noise files, but it was very impressive and high tech (dozens of racks and multiple computer monitors).

They can run at full level for over 1 minute, but then they have to let the stacks cool for an hour before doing it again.

[TOOSTUBBORN2FAIL]

Either way, I'm sure it's far more broadband than a typical spl car which peaks in a 1-2 range, usually around 50-70hz.