GR Research H Frame OB Flatpack $250 + Shipping

Danny Richie · « **Reply #20 on:** 3 Aug 2014, 12:52 pm »

Quote from: bdp24 on 3 Aug 2014, 10:13 am

Danny and/or Jon---Is the round over on the back of the baffle necessary for the frequency range of a sub such as these, used up to 180Hz? I ask because I plan on using bolts to secure the woofers, not screws, and I fear the round over will remove the MDF/BB the threaded inserts for the bolts need.

The round over un-shrouds it a little more and allows for better air flow.

The wood screws that come with it hold it fine. They're rock solid.

jparkhur · « **Reply #21 on:** 8 Aug 2014, 03:24 am »

There a couple of these still available. Shoot me a message if you need a set or four.

JP.

srclose · « **Reply #22 on:** 8 Aug 2014, 10:42 pm »

Funds sent.

Stephen

jparkhur · « **Reply #23 on:** 13 Aug 2014, 03:56 am »

Last pair ready to ship. Great to use with the new reissue of the 8 ohm drivers.
JP.

jparkhur · « **Reply #24 on:** 25 Aug 2014, 01:13 am »

One pair left. Who wants ob subs!

JP

emailtim · « **Reply #25 on:** 5 Sep 2014, 02:14 am »

Quote from: Danny Richie on 30 Jul 2014, 03:43 pm

I might as well spill the beans....

I have a shipment of new woofers coming. The new SW-12-08FR is just like the 16FR version but in 8 ohms. So you can get a little more power out of the amp and a little more SPL when driving just two woofers.

I will still have the 16FR for applications of using three of them per amp.

Hi Danny,

If you can run 2 x 8 Ohm (4 Ohm load) with one amp, what is the difference running 4 x 16 Ohm (4 Ohm load) with one amp ? Wouldn't the load on the amp be the same ?

I would like to get more output while keeping multiples of 2 for force cancellation.

TIA

bdp24 · « **Reply #26 on:** 5 Sep 2014, 05:46 am »

The "16" ohm version is actually 12, and three of them come out at about 4 ohms. Four of them presents too low an impedance to the A370 amp.

Danny Richie · « **Reply #27 on:** 5 Sep 2014, 12:50 pm »

Quote from: bdp24 on 5 Sep 2014, 05:46 am

The "16" ohm version is actually 12, and three of them come out at about 4 ohms. Four of them presents too low an impedance to the A370 amp.

That is correct.

emailtim · « **Reply #28 on:** 6 Sep 2014, 05:24 pm »

Quote from: Danny Richie on 5 Sep 2014, 12:50 pm

That is correct.

That begs the question if the "16 Ohm" are really 12 Ohm, are the "8 Ohms" really 8 Ohm ???

Would 4 - "8 Ohms" work in a dual parallel/serial combination ?

Danny Richie · « **Reply #29 on:** 7 Sep 2014, 03:36 am »

Quote from: emailtim on 6 Sep 2014, 05:24 pm

That begs the question if the "16 Ohm" are really 12 Ohm, are the "8 Ohms" really 8 Ohm ???

Would 4 - "8 Ohms" work in a dual parallel/serial combination ?

All drivers have a rated impedance that is higher than their minimum Re. And most 16 ohm drivers have an Re in the 12 to 13 ohm range. Most 8 ohm drivers have a Re in the 5.4 to 6.2 ohm range..... 4 ohm drivers are often in the 3 ohm range for Re.

With the servo system you cannot series/parallel groups of drivers.

jparkhur · « **Reply #30 on:** 9 Sep 2014, 04:32 pm »

All sold. Thanks.. Have fun... JP

emailtim · « **Reply #31 on:** 10 Sep 2014, 10:54 pm »

Quote from: Danny Richie on 7 Sep 2014, 03:36 am

...
With the servo system you cannot series/parallel groups of drivers.

Danny, Thanks for the clarification.

corndog71 · « **Reply #32 on:** 30 Sep 2014, 06:32 pm »

Last night I finally got around to opening up my packages and I have give a lot of kudos to Jon. Stellar packing job!

The pieces are cut so perfectly I'm afraid I'll mess them up when it comes to gluing, clamping etc. I guess we'll see soon enough.

jparkhur · « **Reply #33 on:** 30 Sep 2014, 06:35 pm »

Quote from: corndog71 on 30 Sep 2014, 06:32 pm

Last night I finally got around to opening up my packages and I have give a lot of kudos to Jon. Stellar packing job! The pieces are cut so perfectly I'm afraid I'll mess them up when it comes to gluing, clamping etc. I guess we'll see soon enough.

Thank you. Did you like the spray foam on the corners? The mdf if it gets knocked always looks bad. Take your time and lay it out. The base and bottom are different from the top, so you should be good. The internal dividers are the same. Remember that the round over for the bottom goes toward you and the other is reverse..

bdp24 · « **Reply #34 on:** 1 Oct 2014, 10:19 am »

Jon---You mentioned there would be an initial run, and then some twenty or so individual frames. Are the individual's the last one's sold, or are they still to be made? You also mentioned that you might make some H-frames out of Baltic Birch. Still to come, or an abandoned notion?

jparkhur · « **Reply #35 on:** 1 Oct 2014, 11:22 am »

I did a few more custom sets during this time. I did two sets in Baltic plus stain to match current speakers, two sets that were painted before shipping. There was not enough interest to do more than 12-14 of them. Partly I feel do to the overall cost of parts for some, others concern over being able to put it together. They were good from those customers I heard back from. It is economics I think. Jp.

corndog71 · « **Reply #36 on:** 1 Oct 2014, 03:53 pm »

If you build any more of those servo amp boxes, I would recommend cutting 45 degree angles on the sides for a simpler and seamless look.

Bottlehead provides simple 4 wall boxes for their kits like this. They're very easy to glue together this way.

jparkhur · « **Reply #37 on:** 1 Oct 2014, 03:55 pm »

Quote from: corndog71 on 1 Oct 2014, 03:53 pm

If you build any more of those servo amp boxes, I would recommend cutting 45 degree angles on the sides for a simpler and seamless look.

Bottlehead provides simple 4 wall boxes for their kits like this. They're very easy to glue together this way.

Thats fair. I did not have one on hand so i was concerned about the fit. I know what you are saying, as I have done those that way in the past.

JP

corndog71 · « **Reply #38 on:** 5 Oct 2014, 06:37 pm »

Can anyone recommend the best order of assembly of these cabinets? I need to buy some clamps.

I'm thinking the base should be the last piece to glue. Im not sure if I should glue each pair of side panels first or glue the baffle to the inner side panels and then attach the outer side panels.

Woodworking is not my forte but I'm trying.

jparkhur · « **Reply #39 on:** 5 Oct 2014, 06:56 pm »

Glue the two side panels first. Then glue top. After top work your way down by putting in spline the dividers till you reach bottom. B

Jon