fEARful™ Part Twelve (12)

[1n3]

Thanks for the instructions on measuring the mid, 1n3. Does it matter if the other drovers are hooked up too?

I'll take a shot, expecting that more knowledgeable parties can correct me. Per my very limited understanding of the CBG crossover, it is very specific to those drivers; if you take them out of the circuit, it won't behave the same. So the drivers need to be connected for an accurate measurement. That complicates measurement, unfortunately.

BTW, the fEARful forum is a better place for questions like this. If you don't find a quick solution, I suggest you take this over there.

 

[rad bassman]

I spent the first few hours of the project marking lines for brads, test fitting and getting the front half of the cab glued together. I came in for some water and she says "Is your new speaker box finished?"

LOL. I get the "Are you done working on your 'thing' yet?"

my sympathies guys, im really lucky by comparison, my gf actually helped me every step of the way, even made the logo

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[Jools4001]

I finished my 15/6/1 late last night (minus the grill). At low levels it sounded great. This morning I cranked it up and there's a problem.

Cab sounds great; no rattles or puffy air escaping noises. It sounds progressively better as you crank it up, but there comes a breaking point. At any volume level up to when the noise starts it sounds great. At what I would consider "loud but not absolutely thundering" volume levels I'm getting a farty noise from the mid. It sounds exactly like voice coil slap or possibly voice coil lead slap. But the VC leads on the 18Sound mid are on opposite sides of the driver. At one point my poweramp went into protect mode. When I turned it back on all was well. Don't know what caused it.

My poweramp puts out 325w@8ohms and I'm not even close to that...the woofer was barely moving and it was LOUD. Maybe too much damping in the chamber? Too litle?

My guess?

Not enough horsepower in the amp department. This sounds exactly like the problem that I had with my Barefaced cab. When I first got the cab I wired up a speakon cable as +1/+2 to plug into channel 1 at the amp end going to a +1/-1 at the cab end. This is pretty standard wiring and was consistent with the wiring schematic on the amp. The result, some weird distortion and the power amp cutting out and going into protect mode. Turns out that the schematic sticker on the amp was wrong (had to open up the amp to find out) and that bridge mode required me to make up a Y cable wired +1 on Channel 1 and + 1 on channel 2.

Cut a long story short, instead of driving it with 600 wats bridged into 8 ohms, I had only been using one channel and pushing 200 watts into it. It was loud but the distortion was the amp complaining. Now that I'm feeding it the full 600 it's got all the headroom it needs.

They're great cabs but do need a lot of watts

 

[mikeddd]

Crossposted over on GB's forums. Here's what he said:

Re: 15/6 fEARfuls...
That's lined, but not stuffed. Not that it would have anything to do with your problem. And what it takes to make a crossed over 18 Sound mid get "voice coil slap" is ridiculously beyond the bounds of almost any amp on the market, if the crossover is functioning. It's unlikely that the mid would even be approaching xmax - let alone xlim. You have not heard voice coil slap.

Model the sucker and see how much wattage it takes to make it go 4mm. And then realize that there's around 3 dB of padding on the mid driver in addition to its awesome real world power handling, and that a fair number of us have used amps in the 1K Watt + range before. So as usual, look to the crossover and the various stages of preamp and amp clipping.

I did some checking and I was watching the level indicators on the front of the amp. They are marked -20, -10, clip. Just as the -10 starts blinking I hear the "farting" a little bit. There's a very fine line b/t lighting up the -10 indicator and the clip light coming on. Once the clip light blinks I get the fart noise bad. The bad sound comes only from the mid though, which is weird. If I'm feeding the cab a clipped signal all drivers should be affected, no?

One other think I noticed; the cooling fan on the amp was spinning pretty fast. It almost never comes on with my Avatar 212. The 15/6 is a much more difficult load, I guess.

I have a PLX3602 which is 700w a side @ 8ohms. I'm going to hook that up and see what the deal is. If that fixes it, I'll bridge my Crown amp and solve the problem.

I'm also waiting for GB to say whether or not I should redo the stuffing in the midchamber since right now, technically it's lined and not stuffed.

 

[mikeddd]

Something is REALLY wrong. I hooked up my monster poweramp (PLX3602) which is 725wpc@8 ohms and right off the bat, the fan spun up and the air coming out was hot. Really hot. Played a little bit at moderate volume. Same clipping/farty problem. I break out the DMM and the impedance of the 15/6/1 at the Speakon is .8 ohms. Not 8.0. (Point eight ohms). I just don't understand what went wrong.

 

[edwinhurwitz]

I think it's time to rip out the crossover and check all your connections. It sounds like you have a short or crossed wire.

 

[Robby Hoinsky]

The bad sound comes only from the mid though, which is weird. If I'm feeding the cab a clipped signal all drivers should be affected, no?

If the crossover is working properly, then most of the higher harmonics introduced by the clipped signal from the amp will be filtered out of the low driver and will only appear in the mid and tweeter.

Robby

 

[Ol'Bass'ead]

If your only showing <1 ohm thats why your amp went into protect mode. I agree with Edwin-youve got a short somewhere.......

 

[::::BASSIST::::]

Just wanted to chime in and say I played my Composite fEARful 15/6 on a couple gigs over the weekend and man that cab has a HUGE low-end. Huge.

I still haven't fully dialed in my tone yet, but I am quite impressed with what I heard so far. Tomorrow is my first outdoor gig with her. Should be interesting.

 

[mikeddd]

If your only showing <1 ohm thats why your amp went into protect mode. I agree with Edwin-youve got a short somewhere.......

Yup. Sad thing is that I know what I'm doing...or at least I thought I did. Time to open up the box, disconnect every damn thing and check one by one.

But that's tomorrow. I'm done with this tonight...too disgusted after all this work for this to happen.

 

[JdoubleH]

my sympathies guys, im really lucky by comparison, my gf actually helped me every step of the way, even made the logo

I realize now what's missing in my life: a girlfriend who will help me build stuff. My wife is useless in that regard.

 

[Sundogue]

Just wanted to chime in and say I played my Composite fEARful 15/6 on a couple gigs over the weekend and man that cab has a HUGE low-end. Huge.

I still have fully dialed in my tone yet, but I am quite impressed with what I heard so far. Tomorrow is my first outdoor gig with her. Should be interesting.

You and I are running nearly identical setups (I run with the BX1200 and 15/6).

If you think you got huge low end now, (I looked at your Graphic EQ), try pushing the 50Hz and 80Hz sliders up more. You'd be amazed at just how deep and loud that fEARful will go!

I have my 50Hz flat, 80Hz at +4 (or even +6), and on my parametric, I have the Frequency on my Lo-Mid set at 100Hz and the control on +4.

When I'm locked in with my drummer and I play on the low B, man it is the sweetest feeling. Yup...definitely HUGE low end. I do though (on outdoor gigs) throw my BP102 loaded 210 under it because I haven't built my 15 Sub yet.

I find that when I run my low end that high, I can cut my 125Hz and kill any mud if there is any present.

 

[::::BASSIST::::]

Interesting. I was actually cutting low end at 50hz, as the graphic shows. We were playing on a large-ish plywood stage that accentuated the lows bigtime. I usually dont have my highend bumped up like that, but the big low-end seemed to be causing the G string to be not as easily heard. Actually, I was told that the G was coming thru loud and clear. I am going to try cutting the 125hz and see what that does.

 

[jnewmark]

Interesting. I was actually cutting low end at 50hz, as the graphic shows. We were playing on a large-ish plywood stage that accentuated the lows bigtime. I usually dont have my highend bumped up like that, but the big low-end seemed to be causing the G string to be not as easily heard. Actually, I was told that the G was coming thru loud and clear. I am going to try cutting the 125hz and see what that does.

How would you compare it to the LDS Nearful you have ?

 

[cableguy]

Hey Bassist,

Yor rig looks pretty sweet. I assume the Carvin BX1500 is rear vented with that rack bag. How you diggin your VT Deluxe as well? That's the set-up I think I will eventually have. But until the cash flow improves I'll just have to be satisfied with my GK 700RB-II. Which by the way is still really loud with my 12/6-12/sub.

 

[::::BASSIST::::]

Hey Guys

Yes, the bx1500 is rear vented and works well in my gator 2u rack bag. It also is a good performer with my 15/6 and VT deluxe. I just bought the VT deluxe from rpsands and I need to spend more time with it. I primarily wanted the multi-channel version so I can emulate a finger stlye tone with a pick and I think I can get it there, but I still need more tweaking. I like the VT alot and it really fattens up the bx1500 nicely. One thing for sure is this rig is very loud. I know I'll never need more than one 15/6 and cant imagine how crazy loud 2 must be. In fact one is pretty much overkill for some of the stuff I do and I could likely get away with using just a 12/6.

As to the comparison between the fearful and LDS 15/6 versions at this point I can say I am certainly hearing more highend from the fEARful and I am guessing thats probably due to the different crossover. I need to gig the fEARful more in a variety of different rooms to get a better idea of the differences. One thing I do like is this composite version seems alot more portable than the LDS cube 15/6 even though it gives off the vibe of a larger cab due its height.

 

[Sundogue]

Interesting. I was actually cutting low end at 50hz, as the graphic shows. We were playing on a large-ish plywood stage that accentuated the lows bigtime. I usually dont have my highend bumped up like that, but the big low-end seemed to be causing the G string to be not as easily heard. Actually, I was told that the G was coming thru loud and clear. I am going to try cutting the 125hz and see what that does.

Yeah, that kind of stage can make a difference. Typically the frequency that causes "mud" is around 125Hz (although the parametric will isolate exactly where it lies, but that is the usual suspect area).

I've found that no matter what room/stage I'm on, if I have to cut low end, it is almost always in that 125Hz neighborhood, which is why I use the 125Hz slider on the graphic...because it will pull down the area centered around that. Allows me to keep the deep lows pushing and I can hear and feel it so much better, without causing that muddiness.

But that's me. I love deep lows. It's difficult for most coming from other commercial cabs to really appreciate just how deep fEARful cabs can go with clarity. Most newbies still EQ their new fEARfuls like they were their old cabs (pushing upper bass/lo-mids and cutting true low end). Until they get used to it that is.

 

[cableguy]

You are right. 95% of the time I run just the 12/6.

 

[::::BASSIST::::]

Yeah, that kind of stage can make a difference. Typically the frequency that causes "mud" is around 125Hz (although the parametric will isolate exactly where it lies, but that is the usual suspect area).

I've found that no matter what room/stage I'm on, if I have to cut low end, it is almost always in that 125Hz neighborhood, which is why I use the 125Hz slider on the graphic...because it will pull down the area centered around that. Allows me to keep the deep lows pushing and I can hear and feel it so much better, without causing that muddiness.

But that's me. I love deep lows. It's difficult for most coming from other commercial cabs to really appreciate just how deep fEARful cabs can go with clarity. Most newbies still EQ their new fEARfuls like they were their old cabs (pushing upper bass/lo-mids and cutting true low end). Until they get used to it that is.

Yeah, that low-end was incredible. Just waves of pure, clean deep bass. Love it!.... bandleader, not so much.

 

[::::BASSIST::::]

You are right. 95% of the time I run just the 12/6.

Yeah the 12/6 is the only thing I have GAS for these days. The only thing I won't like is that its shorter as I like the drivers as close to my ears as possible when on small stages. However, I can always just tilt it back.