Fdeck's HPF

Mike Arnopol · #1 03-18-2012, 09:57 PM

Tb'er Fdeck has come up with a new variable High Pass Filter that has a fixed 12db/octave filter at 35 hz and another variable 12db/octave filer from 35 to 140 hz.

Francis sent me one to try. I've been so busy pumping out cabs that I hadn't had the chance to try it.
My big thing is obviously how does it affect the performance of my cabs. I took a Crazy 8 and got it loud enough for port chuff. I love the word chuff. It's an onomatopoeia. Which means that the word sounds like what it describes. What does port chuff sound like? Chuff. Fortunately the C8 goes very loud before you hear it. Which I'm very happy about.
So, got it to chuff.Plugged in the Fdeck HPF. Didn't even have to get it past the initial 35 hz. Chuff gone.

Took the HPF out. Now don't try this at home. One great thing about the Faital drivers---they go really far without farting out. I played it SO loud (as loud as my 12" 3012ho) and got it to make the nasty sound when the voice coil hits the back plate. Fortunately I don't have to buy the owner of the cab a new woofer. Put in the HPF and dialed it up at the highest setting. The clack was gone. As I expected---but so was the low bass. Kept dialing it down. I wasn't a whole lot past the lowest setting when I didn't really notice the missing bass. But no more voice coil smack. The interesting thing---the C8 actually got LOUDER. I think it was because I was no longer using my amp's recources amplifying crap I didn't want to amplify anyways.
The C8 as well as the 88 go substantially louder with the HPF. Substantially louder. I would tell my customers that the C8 would be fine handling a jazz trio gig with drums at piano trio volume. Let me up that to a quartet with the HPF. Or maybe---shall I say it?---a jazz group with guitar!

I then tried it with electric bass with a C8 + C88 stack. Just set it on the lowest setting. It went louder and sounded more effortless. I boosted the bass until I started chuffing (it was hard to tell--that stack goes really loud---I had to discern between the chuffing and half of my house making weird sounds). I then dialed the HPF up just a bit. Only enough so that I didn't feel like I was compromising the bass sound. Big difference,

I'm recommending it for e-bass too.

I didn't ask for a cut on this nor do I want one. I know that Francis isn't making a bunch of dough here---just a labor of love. I'm just happy that it makes my cabs sound better!

And by the way--in my typical narcissism I failed to mention that it would give any amp and speaker a bigger dynamic range.

BurningSkies · #2 03-18-2012, 10:11 PM

Any news on a release date for the new HPF that's been discussed? Either as finished units or as kits? We've been waiting patiently.

Jeff Scott · #3 03-18-2012, 10:42 PM

I'd like to know more; what is it's form factor, how/where does it hook up in a bass system, pics, etc.

Jim Carr · #4 03-18-2012, 10:46 PM

Pics? Price?

greenboy · #5 03-18-2012, 10:47 PM

It's in prototype.

Jazzdogg · #6 03-18-2012, 10:53 PM

If it also had a VLPF, it could function as a compact crossover to divide frequencies between a crazy8 and a small sub.

JimmyM · #7 03-18-2012, 11:54 PM

Good for F. Good guy who makes a preamp a lot of folks like.

lowfreq33 · #8 03-19-2012, 01:31 AM

I'd love to see 8 of these in a single rack space. I the HPF on my mixer is fixed at 80Hz, and sometimes I'd like a little more flexibility.

**BFunk** · #9 03-19-2012, 01:34 AM

sign me up. i'm very interested.

johnk_10 · #10 03-19-2012, 01:39 AM

so the new one is going to be just an HPF without the preamp? if so, i'd like to buy one as soon as they're available. i think that it would be great to use an adjustable one (35-140hz) in an amp's effects loop, or would the piezo pre one that Francis currently makes be just as good for that?

will33 · #11 03-19-2012, 01:42 AM

Quote:

Originally Posted by lowfreq33

I'd love to see 8 of these in a single rack space. I the HPF on my mixer is fixed at 80Hz, and sometimes I'd like a little more flexibility.

This would be brilliant.

**BFunk** · #12 03-19-2012, 01:42 AM

I hope this takes a line level balanced/unbalanced signal and is unity gain.

**Stumbo** · #13 03-19-2012, 01:45 AM

Quote:

Originally Posted by JimmyM

Good for F. Good guy who makes a preamp a lot of folks like.

Seems like they should come as an option with every speaker cab. Or even standard to get a higher performance out of smaller cabs.

kringle77 · #14 03-19-2012, 04:01 AM

I've been loving my origional fdeck preamp/hpf for awhile. I don't understand how this one is different? I've e-mailed him in the past about doing a HPF/LPF version but, didn't get a response. A great product though.

lowfreq33 · #15 03-19-2012, 04:09 AM

Quote:

Originally Posted by Stumbo

Seems like they should come as an option with every speaker cab. Or even standard to get a higher performance out of smaller cabs.

A lot of bass amps have a HPF built in at a fixed frequency, usually around 20-30Hz. SWR amps come to mind as one that doesn't, at least on the pre-Fender models.

fdeck · #16 03-19-2012, 06:24 AM

Mike, thanks for the report! I'm off to my day job, but will try to provide some more details tonight.

**BFunk** · #17 03-19-2012, 07:10 AM

fdeck - Would you include power requirements? Thanks.

Jim C · #18 03-19-2012, 07:27 AM

There is a review in BGM issue #7 which speaks to its' use with DB.
I don't have a DB but do have an SWR; hmmm this could be a very good tool to have.

http://btpub.boyd-printing.com/publication/?i=98095

mowburger · #19 03-19-2012, 10:23 AM

Interested:

I always use the HPF on my Crown XLS2000 but the lowest freq is 50hz, Would Like one of these actually in my cab.

kris pung · #20 03-19-2012, 10:28 AM

Very interested in this