Fostex FE206E cabinet for Pioneer B20

[drwho]

Hi All,

I built a Fostex recommended Bass Reflex type enclosure for the FE206E FR driver.

This cabinet design is less than satisfactory, specially in the low frequencies.
I am not a bass heavy person but this just won't do!

At some point I shall build a proper back loaded horn type enclosure, but rather than waste this enclosure, could I put the Pioneer B20 8" FR drivers, with a helper tweeter into this?????
Since I already have a pair of these on hand.

This is a 45 liter enclosure.

Scottmoose/Godzilla.....anyone?

Thanks

[rjbond3rd]

Did you build a baffle-step compensation (BSC) circuit? In my limited experience, it seems to be 100% required (unless you were using a BLH). Also, with the FE206E (as opposed to its shielded sibling the FE207E), you might need a few ohms of series resistance to alter the Qes (and thus Qts) of the driver. I'm just parrotting back what's been said here by others.

Allegedly, the FE206E with series resistance can be made to sound very similar to the FE207E and I'm getting gobs of bass from a FE207E in BR with the benefit of a BSC (down to about 55 in a 26-liter). I also heard the Martin King MLTL (his "virtual project #5") with the FE206E and BSC which went right down to 40Hz if not lower.

http://www.quarter-wave.com/Project05/Project05.html

[Scottmoose]

I'm going by memory here but I believe the B20 will go in passably although it's not going to be a bass monster.

[Godzilla]

http://www.zillaspeak.com/pioneerb20-3cubox.asp

Not exactly what you are looking for... but the quick answer is YES the B20 will work in the 45 liter cab. You can seal the port initially for a sealed enclosure - which may be all you want or need for good sound. I live happily with approx a 35 liter sealed box. Adding the port may or may not sound better to you although it will spec better on the charts (providing deeper extension). Tell me what your port dims are now. I will try to calc the port size for you after you tell me your current measurments - diameter and length.

But sealed and stuffed it sounds great. Add helper tweeter of your choice and enjoy!

[drwho]

Thanks guys for your suggestions!

rjbond3rd - I don't know if the BSC circuit would work for me since my design is not MLTL. (Would it work in a regular BR?)


Godzilla - The port diameter is 3 inches x 5 inches Length

Thanks

[rjbond3rd]

Hi drwho, yes definitely BSC is good for BR. I had your exact problem and now I'm as happy as can be.

I think the BSC parts cost around $30 but I did a very simple circuit (just coil and LPad -- two parts!) whereas the more advanced folks do a more elaborate circuit to smooth out the impedance curve as well. I'm a newb so I did the most basic version possible. Anyway, you can adjust to get the exactly right balance between bass and the mid/treble for your situation.

[drwho]

rjbond3rd - I'll have to keep the BSC circuit simple too, since I am a novice at this, but I'll try and figure it out and have a go at it.

Did you buy the parts from Parts Xpress?

Thanks

[gmilitano]

drwho,

A BSC is a very simple correction circuit. It is a function of baffle width and DCR.

Here is an Online Baffle Step Correction / Compensation Calculator you can use to size the BSC components. For more details, see Martin's notes about sizing a BSC.

[GM]

Originally posted by drwho

This is a 45 liter enclosure.

This Vb is very close to a prosound vented alignment (i.e. low Q vent protects the driver over a wider BW), so I recommend using a 2.5" dia. x 6" long vent. Placed near a wall you may not need any BSC.

Note that for the vent to work properly the cab must be well sealed, so wrap tape around the new vent to make it a snug fit inside the existing one and either use more tape or some non-hardening putty such as Duct Seal to seal the gap from the inside of the cab as well as the driver/baffle junction.

GM

[drwho]

Thanks gmilitano/GM

I'll try out both your suggestions GM's first if that doesn't solve the problem than I'll try the BSC.