fostex fw 168 hr problem

[mark adams]

Hi folks, I have a situation that maybe someone can help. I built BR boxes for Foxtex 167 drivers. 23L, Fb 49Hz. When I went to install them the drivers had issues. Long story short, I sent them back. Now I am using FW 168 HR drivers. Fostex called for 14.5 L,Fb to 48-54 Hz My intention is to use these with the FE 126 E BR speakers I now use. Will the 168 work in this box? Also where should I cross these using a low pass crossover ? Thanks for any advice. M

[mark adams]

Sorry. I should have included these links:

http://www.madisound.com/catalog/PDF/fw168hr.pdf

http://www.madisound.com/catalog/PDF...vers/fw167.pdf

[planet10]

It will work in 23L. I'd tune the box lower thou. (i'd pick the 38 Hz tuning)

Attached is 23 litre, tuned (top-to-bottom) to 49 Hz, 45, 42, 40, 38, sealed

dave

[mark adams]

Thanks for your help, Dave. Any thoughts on where you would cross the low pass crossover?

[planet10]

I'd make the FE126 BR aperiodic (stuff the port) and play w XO from its natural LF roll-off up to 200-300 Hz.

What amps do you have (i assume you are bi-amping)?

dave

[mark adams]

Thanks Dave, Yes I am biamping. The 126's are driven with a HK223 I rebuilt. I plan on driving the 168''s with a Adcom GFA2. I planned on using a low pass crossover with the 168's. I was going to try 100 or 120 Hz down. Maybe there is too much roll off in this band of freq.? I could be missing somthing here. Man, I'm a cabinet maker who has educated myself somewhat by lurking on this site and others like it. As a result I have built 2 sets of fe126e BIB for friends that love them. I can't place a BIB in my listening room for now,thats the reason for the BR 126.So the time you and others spend here goes far and wide. Thanks again. M

[planet10]

Originally Posted by mark adams

I was going to try 100 or 120 Hz down.

Then you will be targeting the natural roll-off of the cabinet. The 126 in BR i've modeled struggle to get down to 100 Hz, As well a BR is not the ideal mid-tweeter enclosure. If you make it aperiodic, and add a single cap to the input of the amp you'll have a 4th order roll-off and few problems with the driver unloading at low frequency.

dave

[mark adams]

ok, I will stuff the port then it's no longer a BR. Are you saying it will go lower than 100Hz. on the 126? Then I will raise the low pass for the 168's to 200-300Hz. I hope I have this correct. The cap part I dont get. Sorry. M

[planet10]

No, the FE126 won't get to 100 unless horn loaded. I'm going to guess somewhere between 135-150 Hz (mind you i'm guessing a box size too)

dave

[mark adams]

Thanks for your help Dave. Have a good weekend. M