Rockmeister
pfm Member
Don't start!
building tannoys...beginners help please
- Thread starter Rockmeister
- Start date
ToTo Man
the band not the dog
Rockmeister
pfm Member
point source, I know.
I hope I know, but knowing cooky and FM et al, it won't be 3 mins before someone posts to say that I should be hanging a braced hecto widget from the blinds to dispel some ekto-resonance from the tiled floor bracers with a glue/sheepwool mix only available from russian eco farms
Still I am serious considering porting the speakers at the sides...outward facing and higher. I ain't over till it's over
I hope I know, but knowing cooky and FM et al, it won't be 3 mins before someone posts to say that I should be hanging a braced hecto widget from the blinds to dispel some ekto-resonance from the tiled floor bracers with a glue/sheepwool mix only available from russian eco farms
Still I am serious considering porting the speakers at the sides...outward facing and higher. I ain't over till it's over
Fatmarley
"It appears my intelligence circuits have melted"
Still I am serious considering porting the speakers at the sides...outward facing and higher. I ain't over till it's over
Joe Akroyd knew how to make a bass reflex speaker.
cooky1257
pfm Member
Yes.
Rockmeister
pfm Member
If cooky says yes, then it's yes. I'd put no
. The later HPD's have a different set of specs to the MG's and so cabinet dimensions, crossovers and porting will all vary a little. The basics of timber, framing, bracing and damping might all apply in general terms.Tannoys own cabinets for the 315 were the Cheviot and the Devon I think. See here:
http://www.44bx.com/tannoy/images/Cheviot.gif
http://www.44bx.com/tannoy/images/Devon.gif.
If you want to do your own design, the two vital websites are the cabinet dimension site and the resonance calculator linked in posts 115 and 133. The precise figures to fill in in the former site ref your driver are here:
http://www.44bx.com/tannoy/Tannoy_ts.html#anchor45945.
People have have 50x more experience and knowledge that I do however so! ...
fraserking
Trade: custom speaker cabinets
What a great thread
I’ve built 6 different cabinets with 12” Tannoys over the last 30 years , 3 of them my own proportions , the others based on Devon,Cheviot,Balmoral and they’ve all sounded great. The Balmoral based cabs I have now are the most satisfying of the lot , especially with regards bass - I’ve only got 95/100L after bracing etc as I can’t accommodate the Balmoral actual full depth, but still get clean bass notes down to around 35 HZ before it starts to drop off. I think they are by far the most room/wife friendly of all Tannoy cabs and to my eyes the most attractive proportions . Whatever cabs you decide to make just tweak the port length once you have the cabinets done - I played around with a cardboard tube on the back of mine till I was happy and Cookys tests/graphs proved I was pretty much spot on. I’ll post some pics later.Would definitely recommend spending some money on the main tweeter cap - I ended up getting Clarity MRs for those ( after Ansar , Clarity EAS etc ) and with them became aware of a feeling I could put my hand behind a vocalist head ! Cooky knows what I mean - I don’t think it gets any better than that . Looking forward to hearing how you get on
I’ve built 6 different cabinets with 12” Tannoys over the last 30 years , 3 of them my own proportions , the others based on Devon,Cheviot,Balmoral and they’ve all sounded great. The Balmoral based cabs I have now are the most satisfying of the lot , especially with regards bass - I’ve only got 95/100L after bracing etc as I can’t accommodate the Balmoral actual full depth, but still get clean bass notes down to around 35 HZ before it starts to drop off. I think they are by far the most room/wife friendly of all Tannoy cabs and to my eyes the most attractive proportions . Whatever cabs you decide to make just tweak the port length once you have the cabinets done - I played around with a cardboard tube on the back of mine till I was happy and Cookys tests/graphs proved I was pretty much spot on. I’ll post some pics later.Would definitely recommend spending some money on the main tweeter cap - I ended up getting Clarity MRs for those ( after Ansar , Clarity EAS etc ) and with them became aware of a feeling I could put my hand behind a vocalist head ! Cooky knows what I mean - I don’t think it gets any better than that . Looking forward to hearing how you get on
ToTo Man
the band not the dog
Is it crazy or genius for me to be considering designing a 120L enclosure for the MG12 with two ports, one tuned to 28Hz and the other tuned to 49Hz, to provide the choice to install either the MG12R or MG12HE? i.e. I'd simply block off one of the ports with closed-cell foam? (or socks?!) depending on which driver I install.
Are there any downsides to this, other than the 120L volume being more optimal for the MG12R than the MG12HE?
I'm curious if there would be any difference in how a closure with a single port performs vs an enclosure with two ports but one of them blocked off? I'd imagine there would be a difference since a port blocked with foam/socks is not a reflective surface like a 1" thick cabinet wall, but would the difference be enough to be audible?
Are there any downsides to this, other than the 120L volume being more optimal for the MG12R than the MG12HE?
I'm curious if there would be any difference in how a closure with a single port performs vs an enclosure with two ports but one of them blocked off? I'd imagine there would be a difference since a port blocked with foam/socks is not a reflective surface like a 1" thick cabinet wall, but would the difference be enough to be audible?
Johnjo
pfm Member
I’ve found a slight difference blocking a port with cloths compared to using a piece of plywood with foam gasket. I think it’s slightly aperiodic, it still breathes a little, not necessarily a bad thing.
What about mounting different drivers front and back complete with ports, crossovers and connections. Just spin the cabs round, block the ports and swap the speaker cables over
Get some ABR action going!
What about mounting different drivers front and back complete with ports, crossovers and connections. Just spin the cabs round, block the ports and swap the speaker cables over
Get some ABR action going!
cooky1257
pfm Member
Closest I could get was 120L, 2 ports 100Dx 170L tuning to 40hz, with a very Garner like bass shelf and resonance peak for the MGHE that is almost identical to a 49hz tuning , block one port for MG12R.
ToTo Man
the band not the dog
Sorry Frank, I'm not sure I follow (I'm still on a steep learning curve!). If 120L Fb for the MG12HE is 40Hz with 2 ports 100Dx170L each, what will 120L Fb for the MG12R be with one of the two ports blocked off?
Are you suggesting two ports tuned to 40Hz instead of one tuned to 28Hz and the other tuned to 49Hz because 40Hz is more optimal for the MG12HE in 120L enclosure or because it's pointless having two ports tuned to different frequencies since one will always need to be blocked off? Is this why the three ports in the Legacy Arden are all the same size?
cooky1257
pfm Member
1 100mm dia port @170mm long tunes 120L box to 28hz, 2 ports 100mm dia@170mm tunes it to 40hz. ie one port open suits the 12R, 2 open suits the 12HE. Arden 3 ports with different box tunings depending how many are open.
ToTo Man
the band not the dog
In the Arden, does Fb increase or decrease as you block off the port/s?
Rockmeister
pfm Member
Drivers due soon, so just finalising cab plans. The outside is easy, but the bracing and damping is so fluid an area. Lot's of new research and methods , one a little like a ply construction, but the the inner layer is thin and rigid, and that is glued by a thin glue layer that stays flexible when dry, to a 'soft' outer layer. MDF being 'soft' in this comparison and therefore perfect.
So my decision is to revert to an MDF cabinet (they are then easier to work for an amateur like me...no splintered edges and cheaper to boot) of 18mm thickness (and now lighter by some way) and once that is cut, glue on an inner rigid layer about 7 or 8mm thick to complete the required 25.The cab will then be constructed, framed and the front baffle still braced. Acoustic foam damping goes in after that, and this raises another Q?
Without the damping, the finished cab, with timber and driver and port installed will close as darn it to the 120L I aimed at. But now I'm glueing in 50mm of foam all over the inside! Do I need to recalculate? Or does that foam not count in the interior volume calculation?
So my decision is to revert to an MDF cabinet (they are then easier to work for an amateur like me...no splintered edges and cheaper to boot) of 18mm thickness (and now lighter by some way) and once that is cut, glue on an inner rigid layer about 7 or 8mm thick to complete the required 25.The cab will then be constructed, framed and the front baffle still braced. Acoustic foam damping goes in after that, and this raises another Q?
Without the damping, the finished cab, with timber and driver and port installed will close as darn it to the 120L I aimed at. But now I'm glueing in 50mm of foam all over the inside! Do I need to recalculate? Or does that foam not count in the interior volume calculation?
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Rockmeister
pfm Member
Excellent. Timber and drivers here soon, plans complete. I’ll post the build as it progresses.