Guest atilsley Posted October 21, 2013 Posted October 21, 2013 Just started this new cab, featuring: 15mm Birch Ply (Yates) with lovely Sydney Bluegum veneer. To get the most out of it, likely to use pro spray job in two pack poly high gloss. Size is 150 liters (105cm tall)...room friendly. You see sturdy shelf bracing added. (pricey) Monitor Red 12 inch will be used with standard Tannoy xover. Dual porting to follow, plus 50mm plinth in matching veneer/ply.
ThirdDrawerDown Posted October 21, 2013 Posted October 21, 2013 Looks tasty. Care to let us in to the diary notes behind the choices of dimensions and materials? All the best for the coming months.
Guest atilsley Posted October 21, 2013 Posted October 21, 2013 Looks tasty. Care to let us in to the diary notes behind the choices of dimensions and materials? All the best for the coming months. A couple of things at play here - The dims are determined around overall willingness/capacity to fit a big cabinet in the room. 150 liters is a very good 'mid point' to get bass vs room friendliness. There are quite a few Tannoy cabs that have this sizing. The ply is first rate...normally I use 18mm...but couldn't get the large panel needed at the time, so I went for 15mm. The extra cab bracing will help out. Not shown in the pics, but I will add angled battens on each of the inside panels. You see the round plate at the bottom of the cab. I use left over driver cutouts for panel 'bracing,'....the odd shapes are helpful. Wool/fibre to be added to three walls. Port tuning to be decided...but will follow Arden or similar design.
ThirdDrawerDown Posted October 22, 2013 Posted October 22, 2013 Last time I priced big reds they were A$4.5k for the pair of speakers (I mean they were fully functioning factory tannoy big reds, cabinets, crossovers, complete). Good luck with the build and I hope you get that $5k sound. 1
a.dent Posted October 22, 2013 Posted October 22, 2013 That looks like a nice compromise with the dimensions Andrew. And nice looking veneer. My 270L Monitor Gold cabinets are certainly daunting compared to these. How have you made the calculations for bass port sizes?
Guest atilsley Posted October 23, 2013 Posted October 23, 2013 That looks like a nice compromise with the dimensions Andrew. And nice looking veneer. My 270L Monitor Gold cabinets are certainly daunting compared to these. How have you made the calculations for bass port sizes? Thanks...still working on port size. Low bass not essential for this build...more mid range purity.... I've put a post on the Tannoy Yahoo user group to ask for ideas on port sizing. Are you using 15's...? See this drawing for a puny 700 liter cab... http://www.hilberink.nl/codehans/tannoy103.htm
mrdave Posted October 23, 2013 Posted October 23, 2013 See this drawing for a puny 700 liter cab... http://www.hilberink.nl/codehans/tannoy103.htm Hmmm....there are some 15" Tannoy "Kingdom" bass drivers on eBay. Grab them, some supertweets and a pair of HPD385s, spend some time optimising the crossover and cabs and Hey Presto! A pair of Kingdom Royal killers and $20k change.
Guest atilsley Posted October 23, 2013 Posted October 23, 2013 Hmmm....there are some 15" Tannoy "Kingdom" bass drivers on eBay. Grab them, some supertweets and a pair of HPD385s, spend some time optimising the crossover and cabs and Hey Presto! A pair of Kingdom Royal killers and $20k change. Rock on.... Perhaps x6 31inch subs to add in.......?
Guest atilsley Posted October 23, 2013 Posted October 23, 2013 Having built numerous GRF's...I'd build the large Westminster Royal before the Kingdom....
planet10 Posted October 23, 2013 Posted October 23, 2013 (edited) normally I use 18mm...but couldn't get the large panel needed at the time, so I went for 15mm. The extra cab bracing will help out. Not shown in the pics, but I will add angled battens on each of the inside panels. You see the round plate at the bottom of the cab. That is all the bracing you are going to use? BTW, bracing is more effective if the subpanels have a higher aspect ratio that the panel they are bracing (ie in your cabs the braces would be better vertical) dave Edited October 23, 2013 by planet10
Guest atilsley Posted October 23, 2013 Posted October 23, 2013 That is all the bracing you are going to use? BTW, bracing is more effective if the subpanels have a higher aspect ratio that the panel they are bracing (ie in your cabs the braces would be better vertical) dave I'l still add some vertical bracing off the shelves, plus wall bracing (battens).
Guest atilsley Posted October 23, 2013 Posted October 23, 2013 The inner wall bracing has been added to all panels, making sure the effects of various parameters on the principal instability regions follows Bolotin's approach and finite element method. The first-order shear deformation theory is used to model the resonant frequency of the various MDF and ply pieces used.
mrdave Posted October 24, 2013 Posted October 24, 2013 Having built numerous GRF's...I'd build the large Westminster Royal before the Kingdom.... *nod* My post was made in the context of those 700L cabs you linked to. They suggest 3x12" or 2x15" drivers, hence the 'mega-Kingdoms' I suggested. Gosh those Westminster Royals look fantastic!
Guest atilsley Posted October 24, 2013 Posted October 24, 2013 *nod* My post was made in the context of those 700L cabs you linked to. They suggest 3x12" or 2x15" drivers, hence the 'mega-Kingdoms' I suggested. Gosh those Westminster Royals look fantastic! I can/will/want to build the Westminsters, like this - http://www.diyaudio.rs/topic/2723-diy-tannoy-westminster-royal/#entry54067 Do you want a pair...?! ;-)
mrdave Posted October 24, 2013 Posted October 24, 2013 I can/will/want to build the Westminsters, like this - http://www.diyaudio.rs/topic/2723-diy-tannoy-westminster-royal/#entry54067 Do you want a pair...?! ;-) Check your PMs
Guest atilsley Posted October 24, 2013 Posted October 24, 2013 Panel bracing added to rear of baffle. Decided to add one large port, mounted in the floor (50mm plinth remember...will not have rear panel on plinth for venting). This way, I can test sealed cab and ported.
planet10 Posted October 24, 2013 Posted October 24, 2013 Panel bracing added to rear of baffle. That is not bracing.... you are adding mass to the panel with little gain in stiffness (because it does not reach the edges) you will lower the panels resonance frequency increases the likeliness of the panel resonating. A brace would be edge on and ideally couple to other panels as well as the one it is bracing. dave
Guest atilsley Posted October 24, 2013 Posted October 24, 2013 Dave, those panels on the baffle are for mass as well as bracing. They are placed that way to tie in with the front battens, which I use heaps of poly glue to anchor baffle to sides. Also not show, as not yet built, is full left to right brace I add to opening, which the baffle glues to. You're sounding a little critical without knowing the full details of the build.
planet10 Posted October 24, 2013 Posted October 24, 2013 Dave, those panels on the baffle are for mass Exactly. And since they are flat against the panel, and nottied into the rest of the structure they will not add significant stiffness, lowering the frequency of the panel resonance and make it MORE likely to resonate. Adding mass by itself is NOT a good thing. High density by itself is not a good thing. They are things you put up when they come with substantial gains in stiffness. In your case here, they should degrade the performance of your cabinet. dave
Guest atilsley Posted October 24, 2013 Posted October 24, 2013 ... and not tied into the rest of the structure they will not add significant stiffness, lowering the frequency of the panel resonance and make it MORE likely to resonate. I repeat - They are placed that way to tie in with the front battens, which I use heaps of poly glue to anchor baffle to sides. Also not show, as not yet built, is full left to right brace I add to opening, which the baffle glues to.
cheekyboy Posted October 24, 2013 Posted October 24, 2013 (edited) Hi atisley, I'll be interested in how these cabs turn out and ultimately how they sound. I have a third system using 12" Tannoy Reds in 180 lt cabs that were built back in the early '70s and which I recently re veneered, but I have been contemplating new enclosures for them. Cheers, Keith Edited October 25, 2013 by cheekyboy
Guest atilsley Posted October 24, 2013 Posted October 24, 2013 Thanks Keith...having built MANY large cabinets for Tannoy, Altec, Lowther, Klipsch, GOTO, Carfrae, Feastrex, Fostex etc...I think the sound of these will be very nice. The mid size has been specifically designed to suit the listening requirements and room. As you're in VIC, why not pop over to Earle's place and see the large GRF's I built for him. I've often thought about scaling this horn to 12/15 ths for the smaller Tannoy driver.
cheekyboy Posted October 25, 2013 Posted October 25, 2013 Hi atisley, Earle isn't as close to me as you may think! ..................not that I'd mind paying him a visit. I'm interested in your build in this thread more so, as the Tannoys I have are in a third system and I liked the look of the narrower, taller enclosures you're building as they may be a better fit. Earle's cabs above look to be as big or even bigger than mine below. The pics below are my 12" Tannoy Reds and rear vented via narrow slots cut into the rear baffle. Cheers, Keith
Guest atilsley Posted October 25, 2013 Posted October 25, 2013 Keith, I get what you're saying. SWMBO recently said to me, 'why can't you just have one of those 'little' Tannoys..'? She was referring to one of the 150 liter cabs I built for a gent using 12 inch Golds...quite nice looking, in 25mm Birch ply, and Oak veneer, including hardwood Oak trim. See pic. (Poor photos sorry. I have better photos on different computer.) Another cab I built in the same style was for a 12 inch HPD. See attached. This was American Walnut veneer (quite dark) and featured the larger slotted port, similar to Arden cab. With your rear vent, is there any problem with placement to wall...? Kindly
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