How to design port without driver parameters

[jedcrocker]

Hi,

I'm putting together a cheap center channel speaker using (2) 4x6 automotive speakers in series. I bought the speakers off ebay for $1.65 and the manufacturer states they no longer have the driver specs (?). My searching came up empty except for some other brand 4x6 speaker Thiele-Small parameters (Fs = 117 Hz, Qts = 1.27, Vas = 3.4 L). I've built the enclosure and sized it based on what I need for packaging (it is stacked with the receiver). The cabinet volume is 12 L.

I'd like to tinker with porting to enhance the bass a bit. Can I get in the ballpark on a port without the T-S parameters? I'm new to this so any suggestions are welcome.

Thanks

[Pan]

Pick a 30mm port and try different lengths, if it sounds better to you (once you find the "right" length) then it is better and good.... or something like that..

/Peter

[kelticwizard]

If you have a specific frequency in mind, and you know how to measure your box's internal volume, you don't need Thiele-small parameters to tune a box to a specific frequency.

If that is what you want to do, simply download the simple version of WinISD, (not Pro). Choose any woofer. Model if for a vented box or bandpass, whichever you prefer. Write in your box volume. Write in your desired tuning frequency. And then go to the "Box" section to see what diameter dn length port works.

By any chance, do you have a reliable mic or Radio Shack SPL meter handy? If so, which model number?