petetexas

Experienced Bass Player - mid fifties, looking to form or join a band in Coventry or surrounding area. Music - Lizzy, Free , Doobie Brothers etc - but will play anything ( except Funk ) Own transport, and pro gear.

[quote name='petetexas' post='692918' date='Dec 24 2009, 01:02 PM']Hi Guys, Now fitted and wired up the 4 speakers, linned the inside of the cab, awaiting the two plastic ports to go in back panel. Tried it with my Hiwatt 200 Valve head, with the back panel fitted ( no ports ) sounds very `restricted`. Cant wait till I get the ports fitted. Keep you posted Pete[/quote] Update, Have now fitted the two 100 mm dia ports, and left them 180mm long as bought. Got a tech guy to feed a sine wave, using a signal generator, into my HIWATT 200 Valve Bass Head and the cab, and found that the cab `vibrates` at 22 / 24 Htz. The rest of the time there is is no vibration . The sound is really even and smooth across the fretboard, no particular notes are `booming`. Does this mean the cab is tuned to 23 Htz ? Pete

[quote name='DHA' post='694882' date='Dec 28 2009, 03:15 PM']Yes.[/quote] Thanks............. pete

Hi, Is the output from a valve amp the same, regardless of which ( 4 ohm, 6 ohm or 16 ohm ) selection you use ? Obviously you have to match up to your cab / cabs to the output imp on the amp. Thanks Pete

[quote name='petetexas' post='690468' date='Dec 21 2009, 10:56 AM']Hi Guys, Had a reply from Celestion................. Use two tubes 100mm dia x 125 mm long - but experiment with the length - longer will give more bass, shorter will give more punch. Thanks guys , for all the help...... Will let you know how I get on......... Pete[/quote] Hi Guys, Now fitted and wired up the 4 speakers, linned the inside of the cab, awaiting the two plastic ports to go in back panel. Tried it with my Hiwatt 200 Valve head, with the back panel fitted ( no ports ) sounds very `restricted`. Cant wait till I get the ports fitted. Keep you posted Pete

Hi Guys, Had a reply from Celestion................. Use two tubes 100mm dia x 125 mm long - but experiment with the length - longer will give more bass, shorter will give more punch. Thanks guys , for all the help...... Will let you know how I get on......... Pete

[quote name='alexclaber' post='689221' date='Dec 19 2009, 05:06 PM']Hi Pete, You need to find the T/S parameters for the Celestions and load them into WinISD (Pro is better). Then find the max power handling and then find the port air speed for that power input, and then adjust the port area to get the air speed reasonably low. Once you're settled on a tuning frequency and port area then you can get the port lengths. Test the actual tuning vs predicted tuning with a sine wave generator and some salt on the cone - minimum movement at the tuning frequency. Don't forget to ensure the cab is sufficiently braced and damped before you reassemble it. Alex[/quote] Thanks guys, This is far more complicated than I thought ! ! ! ( The cab is all ply, and braced front to back ) I have sent the info ( volume and type of speakers ) to Celestion, asking for their suggestions. Will keep you posted. Thanks again Pete

[quote name='Mr. Foxen' post='689192' date='Dec 19 2009, 04:41 PM']For ports, 1 flared round one in such a position they you can't see the back of the cones through it is best. However it is not practical. Need to figure where you can put ports first. Download Win ISD to figure the right length once you have figured where you can fit them. I think the rough rule was a port aread of about 1/9th of the cone area.[/quote] Hi, Thanks for reply, have already looked on Win ISD - does not have celestion speakers in, thats where my problem started. Pete

Hi, I have just got hold of a 4x12 speaker cabinet , and 4 Celestion BN 12 -300 S Neo magnet speakers. The internal volume of the cab is about 4.8 cu ft. Any idea what size and how many ports to put in ? Pete

Hi, Just purchased one of these units on e-bay, cannot get the on screen editing software to work. Tried numerous Kork USB-MIDI drivers..................anyone else having this problem ? Pete