Mid-HF section of David for suround cab

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Keryn O'Shea
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Mid-HF section of David for suround cab

#1 Post by Keryn O'Shea » Wed Dec 07, 2016 11:23 pm

Looking to build the Mid-HF section of a David as separate rear surround cabs, purely because I have four 5 inch drivers and a couple of silk dome tweeters for Davids I found in a box from when I was building for others here, that order didn't go ahead. The setup here is 2xTLAH mains (8x4inch), 2xSLA front height (4x4inch), curved centre (6x4inch, no tweeters) and a THT 20inch wide LAB15 loaded. The rear surround cabs here now are a set of full range tower Wellings which have 2x5inch and a silk dome tweeter, the 8 inch woofer not operating as the crossover is set at 100Hz. they are pretty bulky and I'd like to wall mount the rear surrounds and recover a little floor space.
LP is 9 feet from a 55inch TV, the LP is against one wall, TV on the other. Rectangular room, 24 feet long.

Two questions:
-Should I bother or just build couple of SLA 2x4 no tweet surrounds, (or 4x4+tweets) as per the plans (I do like the crispiness of the tweeters in the Wellings)
-How would you calculate the volume of the "David" Mid-HF section?

I know it can be frowned upon experimenting with the designs, be nice!
I'll fit this next panel, then off to bed...

Grant Bunter
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Re: Mid-HF section of David for suround cab

#2 Post by Grant Bunter » Thu Dec 08, 2016 4:49 am

G'day Keryn,
Nice to see you back and hope all is good :)

Mate, you've got the gear, do what you plan I reckon. And let us know how it goes too.

Do you want to know the volume because you're going to port them?

You could do a guesstimate based on the size of the grille backer in the plans, but good luck working it all out as it's all angles lol.

I think Bill has a surround design now too.
Check that out with him...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#3 Post by Keryn O'Shea » Thu Dec 08, 2016 2:57 pm

G'day Grant,
yes mate having a ball as usual, hope your feeling well also. Hope Bunters has been keeping you busy?
Should they be ported? I was thinking sealed.
Asking of volume so I could make the cab depth correct, and yes looking at trying to apply the basic volume formula to the David with all the funky angles was doing my head in! Oh, maybe if you make one rectangle and two triangles of the base to work it out, I'll try that & see what happens.
Bills most likely real busy mate, plus I'm not sure he'd be interested in this.
I'll fit this next panel, then off to bed...

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: Mid-HF section of David for suround cab

#4 Post by Grant Bunter » Thu Dec 08, 2016 3:50 pm

Keryn O'Shea wrote:G'day Grant,
yes mate having a ball as usual, hope your feeling well also. Hope Bunters has been keeping you busy?

Yep, I'm well thanks! Bunters is poking along, getting some odd bigger stuff and a medium amount of solo acts/weddings/DJ type gigs.

Should they be ported? I was thinking sealed.

They should be sealed me thinks as well, was just trying to work out why you wanted volume, but you answered that just below

Asking of volume so I could make the cab depth correct, and yes looking at trying to apply the basic volume formula to the David with all the funky angles was doing my head in! Oh, maybe if you make one rectangle and two triangles of the base to work it out, I'll try that & see what happens.

That's how I'd go too. Remember two triangles is one rectangle ;)
As far as the dimensions for calculations, a bit of averaging will help make it much easier. Say half way between the 2 different faceplate widths x depth etc.


Bills most likely real busy mate, plus I'm not sure he'd be interested in this.
I think you misunderstood. Bill has an (I think) SLA surround design now. You might like to compare it to your ideas...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Bill Fitzmaurice
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Re: Mid-HF section of David for suround cab

#5 Post by Bill Fitzmaurice » Thu Dec 08, 2016 4:30 pm

Grant Bunter wrote: Bill has an (I think) SLA surround design now. You might like to compare it to your ideas...
It's been in the SLA plans for a year.

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#6 Post by Keryn O'Shea » Thu Dec 08, 2016 5:17 pm

Yes, just received the SLA plans update this week and the 2x4 surround will definitely make it into the other living room, as they would be easy to bolt to a wall or wherever you want them. The 3 inch versions are tasty as well!
Thanks very much Bill, way to keep us busy!
I have the week off after new year, and plan to lock myself in the shed to sand and paint a few HT cabs I couldn't wait to hear, especially the THT, man that thing cranks! Turns out I didn't have the room for a T60.
I'll nut out a cab size for this experiment soon and get cracking.
I read somewhere that using an AT for HT is classed as abuse, but I removed it from the van before I sold it and wired it to an existing Pioneer 25w active sub amp in our other living room, wedged it on top of the wall cabinet in the corner and it's not stressed at all, the gain is set at half and easily does a great job!
I'll fit this next panel, then off to bed...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#7 Post by Keryn O'Shea » Thu Dec 08, 2016 5:55 pm

Also is there going to be GT-302's in stock anywhere ever again? The 4x4inch SLA's here have the holes for, but no tweeters installed.
I found what looked like a clone tweeter on ebay, but before I could order them that store closed down.
I have 6 here, but keeping them for spares for the TLAH.
Can the KSN-1016's be used for HT? Thinking no
I'll fit this next panel, then off to bed...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#8 Post by Keryn O'Shea » Fri Feb 17, 2017 2:11 am

So found some GT-302's. Looking in the latest SLA plans for the 6 and 9 tweeter high pass filter diagrams, which one is for which? The diagrams are vertical, but the text is on the horizontal underneath. Thinking the top one is the 6 tweeter.
Trying to finish other cabs before I launch into the "David" Hf experiment. Ultimately I'm thinking they would do better as an upgrade as mains to our other TV room with the AT, because I sat on the far side of the couch in the main room with the tower speakers as surrounds, and it was a annoying half way through the movie as I couldn't hear the other surround speaker, and it ceased to be "surround sound", and having tweeters made it worse.
So now I don't know what to build (for surrounds) as when you sit on the couch the ceiling above is not level, it pitches away to your right to the center of the ceiling and the TV is up one end of the room.
I'll fit this next panel, then off to bed...

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LelandCrooks
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Re: Mid-HF section of David for suround cab

#9 Post by LelandCrooks » Sat Feb 18, 2017 8:40 am

I have a crapload. Just got them. I need to get them up on the site. Too many irons in the fire again.
If it's too loud, you're even older than me! Like me.
http://www.speakerhardware.com

Keryn O'Shea
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Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#10 Post by Keryn O'Shea » Tue Feb 21, 2017 3:35 am

Great, we'd rather buy from you mate.
I'll fit this next panel, then off to bed...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#11 Post by Keryn O'Shea » Mon Mar 06, 2017 8:28 pm

Had time to mock this up today. The volume of the David section came to 12 Litres, converted back ended up with a cab 18x 7.75x 5.75 inches (I'm no maths wizz though). To give it shape I used the David Grille backer profile for the baffle, and went 5.75 deep.
It does however look like Darth Vaders helmet, which doesn't quite show in the photo's. I'm hoping once the corners are rounded it should soften the angles, also Black paint will most likely exaggerate the helmet look.
So definitely not a surround cab, but they should make a mean set of PC/Laptop speakers (where I'll be trying them first with an AT in my office), maybe mini mains for a small listening room with sub/s? Could they be used as monitors?
Just waiting for filter components to arrive before I can hear them.
Attachments
20170307_105625.jpg
I'll fit this next panel, then off to bed...

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: Mid-HF section of David for suround cab

#12 Post by Grant Bunter » Tue Mar 07, 2017 4:06 am

Keryn O'Shea wrote:Had time to mock this up today. The volume of the David section came to 12 Litres, converted back ended up with a cab 18x 7.75x 5.75 inches (I'm no maths wizz though). To give it shape I used the David Grille backer profile for the baffle, and went 5.75 deep.
It does however look like Darth Vaders helmet, which doesn't quite show in the photo's. I'm hoping once the corners are rounded it should soften the angles, also Black paint will most likely exaggerate the helmet look.
So definitely not a surround cab, but they should make a mean set of PC/Laptop speakers (where I'll be trying them first with an AT in my office), maybe mini mains for a small listening room with sub/s? Could they be used as monitors?
Just waiting for filter components to arrive before I can hear them.
Looking good Keryn!
Always loved your work mate.

Laughed a lot at:
It does however look like Darth Vaders helmet
Sure, try them on your PC.
Did you mean studio type monitors?
You might want a little lower in cab tuning for that (or slightly lower Fs in the mid drivers), but hey, the drivers are at least in the right alignment for accurate listening...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#13 Post by Keryn O'Shea » Sun Mar 19, 2017 3:50 am

So I had to paint them in duratex to match everything here, if only there was somewhere which sells chrome bezels in a million sizes to inlay into the backmount to break up the black, unless someone has a suggestion?
Still waiting for filter bits to hear them, but I'm sure they'll be lovely.
Grant Bunter wrote:Did you mean studio type monitors?
Yea Grant, a stretch for studio type monitors, you're right!

The camera on my phone seems to have a weird "fisheye" type of thing going on, but the left cab is closer to what they actually look like, just taller.
Attachments
20170319_171850.jpg
I'll fit this next panel, then off to bed...

Keryn O'Shea
Posts: 210
Joined: Sat Jan 26, 2013 5:50 pm
Location: Brisbane, Australia

Re: Mid-HF section of David for suround cab

#14 Post by Keryn O'Shea » Sun Mar 19, 2017 4:01 am

LelandCrooks wrote:I have a crapload
The GT-302's showed up yesterday too mate, so glad to see them thank you, now I can finish off ....and start some more!
I'll fit this next panel, then off to bed...

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