GR Research Brute Speakers

BrandonB · « **Reply #20 on:** 14 Sep 2023, 03:24 am »

This is a question for Danny or Hobbs. Will you be able to use a hi-pass filter on the Bully or Beast from your preamp to the servo's subs?

emailtim · « **Reply #21 on:** 14 Sep 2023, 07:21 am »

I have some Brute questions if anyone can answer:

1) What does "Old School" mean in the Brute's description (e.g. Rock and Roll speakers like old 70/80's Cerwin Vega or Heritage Klipsch of the same era) ?
2) Can the kit be purchased without the CNC'd MDF flat pack (DIY cabinet and schematic) ?
3) If the upper chase next to the MT is empty (no internal porting holes), would tapering the top triangle corner angled back help make the baffle narrower for better imaging ? The Brute video indicated the wider baffle imposes a slight performance delta over the smaller baffles.

Thanks much.

corndog71 · « **Reply #22 on:** 14 Sep 2023, 11:59 am »

1. It’s old school as in it’s a big box speaker with a big woofer.
2. The kit is separate from the cabinet and yes, cabinet plans are there on the website.
3. The whole cabinet volume is utilized aside from bracing.

emailtim · « **Reply #23 on:** 14 Sep 2023, 07:08 pm »

Quote from: corndog71 on 14 Sep 2023, 11:59 am

1. It’s old school as in it’s a big box speaker with a big woofer.
2. The kit is separate from the cabinet and yes, cabinet plans are there on the website.
3. The whole cabinet volume is utilized aside from bracing.

Thanks much. I mistakenly thought the MT went into the 2-well side, not the single well side.

Presb4 · « **Reply #24 on:** 15 Oct 2023, 10:28 pm »

So, I haven't post on my build in a bit as my work took me out of town for the last month, but I'm back home now.

Today I was able to get the Norez cut up and added to the cabinets. FYI, I found the norez some what tough stuff to cut. The backing on it is kind of thick and gummy. In the end I found that my little band saw made quick work of getting it cut and I think it worked better than using my table saw.
I then added pink fiber glass in all the nooks and crannies.

Presb4 · « **Reply #25 on:** 16 Oct 2023, 12:30 am »

Norez and glass applied

Presb4 · « **Reply #26 on:** 16 Oct 2023, 12:34 am »

Tyson · « **Reply #27 on:** 16 Oct 2023, 01:58 am »

Looking good

Presb4 · « **Reply #28 on:** 17 Oct 2023, 02:42 am »

Thanks Tyson

Danny Richie · « **Reply #29 on:** 17 Oct 2023, 02:22 pm »

Absolutely nice work.

Presb4 · « **Reply #30 on:** 21 Oct 2023, 02:42 am »

Ok, the front baffles are on and the glue has dried.

Food for thought on the glue topic. I had seen other speaker builds with many suggesting the use of titebond III glue, and that is what I used for the basic cabinet glue up. But I found that it set up quicker than I would have liked, leaving me little time to make adjustments if I had a panel out of plumb.

For the front baffles I had some Locktite PL 3x in the shop left over from a different project so I figured I would give it a go. I found it to fill some minor gaps I had in the front baffle better than the titebond glue and it provided longer fit up time to get everything perfect for clamping. In the future I would recommend others give PL 3x glue a try.
One note on using PL 3x, it does expand as it cures, so make sure you have it clamped up good before you walk away.

Presb4 · « **Reply #31 on:** 21 Oct 2023, 02:47 am »

Next was getting all the edges cleaned up and ready for the router.
It was a beautiful fall day for sanding outdoors here in Minnesota

Presb4 · « **Reply #32 on:** 21 Oct 2023, 02:54 am »

Then it was off to the router table.
I first tried a 3/8" quarter round bit, but settled on a 1/2" quarter round bit in the end.
I decided to use the router on all sides. These speakers are not lite, and I imagined that if I left any right angle edges on these cabinets that they would get dinged up quickly when moved. As you can see the 1/2" bit cut right up to the edge of the 12" woofer cut out.

BrandonB · « **Reply #33 on:** 21 Oct 2023, 03:23 am »

Quote from: Presb4 on 21 Oct 2023, 02:54 am

Then it was off to the router table.
I first tried a 3/8" quarter round bit, but settled on a 1/2" quarter round bit in the end.
I decided to use the router on all sides. These speakers are not lite, and I imagined that if I left any right angle edges on these cabinets that they would get dinged up quickly when moved. As you can see the 1/2" bit cut right up to the edge of the 12" woofer cut out.

Looks good. Did you use a flatpack? How are you going to finish it?

Presb4 · « **Reply #34 on:** 21 Oct 2023, 03:57 am »

I use a flat pack. I took one look at the CAD dwg and it would have been over my head to cut all those bracing sections correctly and have them fit right.

I was going to veneer them, but decided to just go the Duratex route for now. I can always go back and veneer them in the future.

Tomorrow is paint, then mount the crossover and wire...I can see the light at the end of the tunnel

hawkeyejw · « **Reply #35 on:** 22 Oct 2023, 01:58 pm »

Nice work! You also have me thinking about that litttle band saw for making mitered cuts in the no-rez when I finally make time to build out my NX-Studios. My cheap table saw didn’t cut it well either.

Presb4 · « **Reply #36 on:** 23 Oct 2023, 10:22 pm »

Quote from: hawkeyejw on 22 Oct 2023, 01:58 pm

Nice work! You also have me thinking about that litttle band saw for making mitered cuts in the no-rez when I finally make time to build out my NX-Studios. My cheap table saw didn’t cut it well either.

Yes, it would work great for that purpose.

Presb4 · « **Reply #37 on:** 23 Oct 2023, 10:24 pm »

Ok, all ready for the Duratex painting.

Tyson · « **Reply #38 on:** 23 Oct 2023, 10:28 pm »

Those things look heavy.

Presb4 · « **Reply #39 on:** 23 Oct 2023, 10:30 pm »

2 coats of duratex later and it was all done. I had to paint everything but the back side first and then flip them over after front and sides were painted and dry, then I painted the back. I had some painters pyramids and tried using them but these Brutes are to heavy to flip without getting paint all over you and the work bench. Ask me how i know