Stevie’s 12” FRFR Cab Build Thread (Basschat Cab v3)

[funkle]

Thanks Phil

Sounds like some helpful stuff to try. I’ll see what I can do. 

I was a bit iffy on the T-nuts holding perfectly with just hammering them in, so just before I tried installing the woofer, I did in fact take a washer and bolt and then tighten a bolt in each hole, and make sure the T-nuts were firmly held into the wood. This one came out anyway. 

I have heard it said T-nuts can have a little glue on them to help them stay in. I may try that if I can rescue this one. 

I have read @Bill Fitzmaurice on another forum say that he thought T-nuts were more hassle than they were worth. I only read that now after Googling for solutions, though, lol...

 

[stevie]

Phil's suggestion of pulling the T-nut out to re-engage the spikes is definitely worth trying. However, I suspect that the bolt is tightly jammed and the T-nut might not hold.

If you can get the mole grips to grip the T-nut tightly - you'll need to experiment with the adjustment a bit - jam the handles of the mole grips against the side of the cab. Then turn the bolt.

When you get the bolt out, you'll need to fill the bit of the baffle that the T-nut has gouged out. Unfortunately, the Everbuld wood filler you have is only meant for use in thin layers, although it might work depending on how much wood the T-nut has removed. Two-pack wood filler or car body filler will work and will allow you to reinstall the T-nut. Araldite is another option. With any of these fillers, you'll need to re-fit your T-nut before they set hard.

I think that repairing the hole will be a lot less work than filling all the existing holes and drilling new ones.

If you need another T-nut, I can send you a couple on Monday - just let me know. When you've removed the offending T-nut, there's nothing to stop you finishing off the cab and trying it out. Just stick some Blutac over the spare driver hole.

[stevie]

The way I understand the problem, Phil, is that the bolt has been cross-threaded and has jammed in the T-nut. Turning the bolt has forced the T-nut round, gouging out a circle in the rear of the baffle. So the T-nut is now spinning round but not gripping anything, and the bolt is stuck in the T-nut and won't come out.

[nilebodgers]

T-nuts are an inherently cheap&nasty item - I built a lot of PA cabs back in the day (over 50) and I could reckon on a significant percentage having a duff thread. I ended up testing them all first to save re-work time. Not an option that would work for real volume manufacture, but I'd do it on one-offs or small batches.

[funkle]

15 minutes ago, stevie said:

The way I understand the problem, Phil, is that the bolt has been cross-threaded and has jammed in the T-nut. Turning the bolt has forced the T-nut round, gouging out a circle in the rear of the baffle. So the T-nut is now spinning round but not gripping anything, and the bolt is stuck in the T-nut and won't come out.

Absolutely spot on Stevie. Nice summary. 

I did try pulling the T-nut back up into the baffle, but I can’t get purchase any more. 

@stevie I have plenty more T-nuts, should be ok. I’m keen to get the cab going so may just do the BluTac option while I try and get a filler. 

[basstone]

If the T-nut is locked completely solid and you can't get to the back to grip it, can you pull the woofer far enough back from the baffle to get a hacksaw blade in from the edge to cut through the bolt shaft? may be easier than drilling the head off?

[funkle]

I’ll see how it goes when I get home. I have no desire to get a hacksaw anywhere near the driver...or my drill, for that matter...fingers crossed. 

[nilebodgers]

Mini angle grinder will make short work of the bolt if you can get it in there.

[funkle]

Ok, good news. I managed to lever up the woofer and, after a lot of fiddling, get the mole pliers locked on, and unscrew the bolt out. 

When I checked the state of the hole behind, it actually didn’t look too terrible, and a T-nut still fit within it. I didn’t have time to get Araldite, but I did have some Loctite (not the same, but good enough as it turned out). 

I ran Loctite on to the ‘catching’ surface of the new T-nut, pressed it into place, and when it dried, ran some more around that. Then threaded a bolt in by hand to check it all worked ok. It did. 

@Phil Starrmade an important point about using T nuts. I unconsciously, I think, was leaning in hard against it when I was trying to thread the bolt in the first time around. So I made it pop out, especially when I cross threaded it by accident at the same time; it made it easy to apply too much force. 

Having determined that, I was wanting to avoid any issues this time around. So I hand screwed in every single bolt on the woofer to make sure none of them cross-threaded, making sure not to lean or press down when doing so, until they were all about half way in. 

Only then, did I use the Allen key to tighten them all to the full tightness. So, it’s now all put together.

Tomorrow I’ll test it out and see if I’ve wired everything in right. Hopefully so! Then I can look at sorting the grill and badge. 

By the way, current weight: 28.3 lbs. Nice!!!

Edited September 7, 2019 by funkle

[stewblack]

TOMORROW?? 

 

You have patience beyond the power of human imagination. 

[funkle]

1 minute ago, stewblack said:

TOMORROW?? 

 

You have patience beyond the power of human imagination. 

Lol. I have a house with 2 asleep young children and a tired wife. No way I can do anything tonight...the patience is forced, not voluntary...

Edited September 7, 2019 by funkle

[Pea Turgh]

33 minutes ago, funkle said:

Ok, good news. I managed to lever up the woofer and, after a lot of fiddling, get the mole pliers locked on, and unscrew the bolt out. 

When I checked the state of the hole behind, it actually didn’t look too terrible, and a T-nut still fit within it. I didn’t have time to get Araldite, but I did have some Loctite (not the same, but good enough as it turned out). 

I ran Loctite on to the ‘catching’ surface of the new T-nut, pressed it into place, and when it dried, ran some more around that. Then threaded a bolt in by hand to check it all worked ok. It did. 

@Phil Starrmade an important point about using T nuts. I unconsciously, I think, was leaning in hard against it when I was trying to thread the bolt in the first time around. So I made it pop out, especially when I cross threaded it by accident at the same time; it made it easy to apply too much force. 

Having determined that, I was wanting to avoid any issues this time around. So I hand screwed in every single bolt on the woofer to make sure none of them cross-threaded, making sure not to lean or press down when doing so, until they were all about half way in. 

Only then, did I use the Allen key to tighten them all to the full tightness. So, it’s now all put together.

Tomorrow I’ll test it out and see if I’ve wired everything in right. Hopefully so! Then I can look at sorting the grill and badge. 

By the way, current weight: 28.3 lbs. Nice!!!

That looks booming!

[mcnach]

That looks superb, well done!

[funkle]

Well, finally, I got to sit down and test it. Thankfully it sounds like everything is hooked up right. Used my GK MB800 head as the amp.

One must be careful when describing a cab one has built, because there is going to be some bias. Lol

That said, it sounds like this:

This is the frequency response chart of the cab that Stevie sent me. It sounds like that - everything is very balanced, top to bottom. (NB: frequency range on chart is 200Hz - 20kHz).

The highs are really clear and present without being harsh. Superb. I have a Celinder Update which tests treble perfectly - it has about the most top end I’ve heard out of an instrument.

This cab shows one of the delights, and pitfalls, of FRFR cabs. Every single string noise and bit of technique is highlighted - you must be very clean in playing. I elected to turn down a bit of the treble knob on both my Celinder Classic Jazz and the Celinder Update and I still had all I needed treble wise. Yes, I did the Marcus Miller slap thing and it sounded fantastic.

The highs here are similar as the very best cabs I have heard in this area - the Fearless F112 and the Barefaced BB2. I’ve always said I liked the BB2 highs just a little better than the F112, but this cab I think pips the BB2. It’s close though.

One of the design goals of the cab is that you can be immediately in front of the cab and hear yourself well. It achieves this well. 

The mids are even and I hear every instrument’s character clearly, mid EQ tweaks are clear. Very smooth.

The lows I tried out in a few different ways.

Keeping the cab off the floor on my workbench, the lows were even and clear, and you could EQ in a huge amount if desired. I always like to push cabs here and see if I can make them fart out. I maxed out both the bass boost on the amp and the John East J Retro pre - which is a frankly insane amount of boost - before I could get the woofer to distort a little. Took it like a champ.

(The only cabs I have never seen distort with that much boost are the Fearless F112, which already has a walloping low end [probably a bit too much, but it is intoxicating], and the Audiokinesis Thunderchild. No coincidence that both share the mighty 3012LF woofer. However I often found myself turning down the low end on those cabs.)

Once I put the cab on the floor to get the boundary effect giving a moderate bass boost, the cab sang. Beautifully meaty, tasty tone. Gorgeous. Balanced. Responsive to EQ and hand placement. Insert your favourite hyperbole here. Etc

It took the B string well also. An even volume with all the other strings, even when turned up. No issues there at all.

I do wonder if the cab will open up even more on the low end as I play through it. Wait and see I guess. 

Loudness. I haven’t fully tested it - it needs gigged at volume for a period of time to fully judge. That said, in my opinion it is louder than the F112 and equal to what I remember of the BB2. Very, very, very loud with 500W. Windows rattle, the house shakes, and I hadn’t even tried maxing out the gain/volume. I’m going to need to make sure no-one else is in the house before I can do that. For me it is certainly a one cab solution for anything I will play.

Take what I say with a pinch of salt. I built it, after all. But in my opinion the nearest cab I can think of to compare it to sonically is the BF BB2. It feels like boutique performance for a lot less money. It’s an FRFR cab without a doubt.

 

Edited September 9, 2019 by funkle

[funkle]

I still need to finish some bits off, now I know it works. 

Turns out I forgot to put the woofer foam on:

D’oh.

Then I’ll need to sort out the grille and badge. It should end up looking like this:

That may happen later on today, but I have family stuff to do, so might be next week. 

I’m satisfied this won’t end up looking like a home build. That has been my main goal. 

Edited September 8, 2019 by funkle

[baldwinbass]

Excellent, a proper job - well done 👍

[Chienmortbb]

34 minutes ago, funkle said:

I still need to finish some bits off, now I know it works. 

Turns out I forgot to put the woofer foam on:

D’oh.

Then I’ll need to sort out the grille and badge. It should end up looking like this:

That may happen later on today, but I have family stuff to do, so might be next week. 

I’m satisfied this won’t end up looking like a home build. That has been my main goal. 

It looks a lot like mine....... but a lot better.

A for the T nuts, I think they must be glued as well as using the spikes.  I think that eight wood screws would work well enough however as each screw would be expected to hold less than 0.5kg. Of course, as with clamping,  there is no need to over-fasten the fasteners.

[tauzero]

I suspect that pushing the T-nut out slightly would almost certainly make it skew, meaning it would be more likely to cross-thread. Must remember to be gentle.

[stewblack]

Well done, fantastic work. But one important question. Badge placement.... Always been a top left kind of guy myself. Or a bottom central. What is the guidence here? 

[Chienmortbb]

Best to go Top Left or bottom somewhere. Top right might interfere with the port. 

[funkle]

12 minutes ago, Chienmortbb said:

Best to go Top Left or bottom somewhere. Top right might interfere with the port. 

Hmm. I had hoped it would be safe there...maybe if I scooted it up an inch above the port?

Edited September 8, 2019 by funkle

[funkle]

I need to look at double sided sticky tape as well to get it fixed into place. 

[LukeFRC]

44 minutes ago, funkle said:

Hmm. I had hoped it would be safe there...maybe if I scooted it up an inch above the port?

It was designed to sit top right - I think an inch from each edge of baffle gave enough clearance of the port that @stevie was happy.  Obv adjust to taste based on what you think and what looks good! 

 

Talking of which - I kept my sticker rather than post it to you Stevie to post it back - you will have to let me know my number

[Phil Starr]

Well done all the people who contributed to this project. I'm sure there is plenty more to come when funkle has gigged the cab and we get more impressions of how it is working in practice, plus of course more impressions once the rest of the kits get built. My hope is that this design will go on to be a classic self build classic like the Greenboy designs.

I know a lot of basschatters have contributed to the design and development, I applaud them all. This has been a truly cooperative project but of course one person deserves particular thanks. Well done Stevie 

[funkle]

Hear hear to that!