What would you recomend?

[bobgpsr]

[quote=mayhem13;97368]

eyekode wrote:

Have you ever experienced any unusual port noises with your builds?

I have heard port noises with my SVS PC-Ultra 12" when having two ports plugged at high volumes. So went back to just plugging one port and not pushing the SPL levels.

That is why my DIY project with a big Xmax 15" driver used two 18" 2500 gram passive radiators. If I was going to toil over building a heavily braced baltic birch enclosure -- I did not want to contend with port noises or organ note resonances from ports that were too long. Money spent on the PRs was worth it considering my build time investment.

[mayhem13]

Ah ha- thats they key-can we really here these artifacts in actual listening tests. A mic can hear and plot it but by the time the acoustics of our listening spaces are done adding their own colorations in far greater volumes, the actual issues produced by the system in question are overwhelmed. So in reality i guess what i'm saying is in our own listening spaces designs may have to be modified to cope with room modes which i have never bothered to measure or analyze. I must just be lucky for my main listening space is very open and no side walls to interact with standing waves. I had an older CV 15" sub that sounded pretty good in this space believe it or not. I've gotten my refurbished JL W713's and will start a build next month so this will be the test. No matter how i model them in a ported enclosure, i can't tame port air speed, compression or 1st resonance. I'm gonna feed then 2800w parallel and watch my windows swell at 18hz-122db-i doubt i'll hear anything from the ports (6" dual) above the drivers output but we will see. I bet if i turned my mains off i might catch a glimpse of something though.

[eyekode]

mayhem13 wrote:

Ah ha- thats they key-can we really here these artifacts in actual listening tests. A mic can hear and plot it but by the time the acoustics of our listening spaces are done adding their own colorations in far greater volumes, the actual issues produced by the system in question are overwhelmed. So in reality i guess what i'm saying is in our own listening spaces designs may have to be modified to cope with room modes which i have never bothered to measure or analyze. I must just be lucky for my main listening space is very open and no side walls to interact with standing waves. I had an older CV 15" sub that sounded pretty good in this space believe it or not. I've gotten my refurbished JL W713's and will start a build next month so this will be the test. No matter how i model them in a ported enclosure, i can't tame port air speed, compression or 1st resonance. I'm gonna feed then 2800w parallel and watch my windows swell at 18hz-122db-i doubt i'll hear anything from the ports (6" dual) above the drivers output but we will see. I bet if i turned my mains off i might catch a glimpse of something though.

Heh... at 122db 18hz you will hear all kinds of crap. And I agree it will probably be hard to discern port noise from walls, doors, cups, coasters, blinds, pictures rattling around. My guess is if you leave that on for a minute or two you will begin to feel sick. That much infra-sound cannot be good . When testing my sub for ~15 mins running mostly sine waves I felt physically bad when I was done. And I didn't even break 100db.