View Full Version : Cabinet Plans for Tannoy HPD 385
Does anyone have any cabinet plans suitable for Tannoy HPD 385s?
I am seriously considering rehousing my drivers from their current Lockwood Academy enclosures as they are on the small side at 68L and I feel the bass is lacking a bit of impact and weight causing the presentation to sound too mid-centred.
I thought I would start gathering ideas with a view to possibly building over the winter.
I have a nice pair of solid oak stands which I'm using at present but I think to get a decent internal volume we're realistically looking at a floorstander rather than a standmount design.
I'm thinking bass reflex rather than horn loaded. Obviously the Arden is out there but having looked at a lot of Tannoys online I think the closest to what I'm looking for is the York and I would prefer the rectangular style to the corner type. Tweeter height of around 34-36" would be ideal. Ardens are a much lower height.
My room is 13 x 11 with an 8ft ceiling which tapers at the listening end.
Anyone anything they could share or any advice gleaned from experience, either would be greatly appreciated.
Thanks, John
walpurgis
22-09-2018, 20:45
Take your pick: https://www.google.co.uk/search?q=tannoy+cabinets+plans&client=aff-maxthon-maxthon4&hs=Wgr&affdom=maxthon.com&channel=t31&dcr=0&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwjWg4mOvc_dAhUI2qQKHYV0AWoQsAR6BAgEEAE&biw=1271&bih=653
Take your pick: https://www.google.co.uk/search?q=tannoy+cabinets+plans&client=aff-maxthon-maxthon4&hs=Wgr&affdom=maxthon.com&channel=t31&dcr=0&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwjWg4mOvc_dAhUI2qQKHYV0AWoQsAR6BAgEEAE&biw=1271&bih=653
The only one of those suitable as far as I can see is this, the rest are either horn loaded or for smaller drivers.
http://ukhhsoc.torrens.org/makers/Tannoy/Cabinets/York_rectangular.jpg
walpurgis
22-09-2018, 21:05
The York is the predecessor to the Arden. Both enclosures are suitable for 15" Golds and HPD's. Best used on short stands or plinths and both benefit from additional internal bracing.
fatmarley
22-09-2018, 21:21
A Tannoy is no different from any other speaker when it comes to low frequency tuning. There's this common internet myth that Tannoys are somehow immune to the laws of physics and that you can just stick them in a massive box and everything will be great. If you make the box bigger than they are supposed to be in and tune lower, you will get more low frequency extension but the overall bass level will be lower than the midrange/treble (easy to model in any software).
The only time you could get an improvement is when something is wrong in the first place, eg - bass is peaky so you can tune lower or it's a sealed box, so you could possibly port them to gain more extension. Is the Lockwood a sealed box? Most Tannoys are designed for porting.
If it were me, i'd open the enclosure and find out what crossover it has (standard Tannoy or something Lockwood designed?). I don't know the model numbers but lets say the driver and crossover are for a York, then that's what i'd build.
John
Have a chat with Paul at RFC. I'm sure he could design something unique that fits your style, your room and optimises your HPDs.
Knowing Tom's and Adam's RFC designed cabinets I'm sure you would be delighted what Paul could do.
The York is the predecessor to the Arden. Both enclosures are suitable for 15" Golds and HPD's. Best used on short stands or plinths and both benefit from additional internal bracing.
Where does the Amesbury fit in there Geoff, is that the proper name for the rectangular York?
A Tannoy is no different from any other speaker when it comes to low frequency tuning. There's this common internet myth that Tannoys are somehow immune to the laws of physics and that you can just stick them in a massive box and everything will be great. If you make the box bigger than they are supposed to be in and tune lower, you will get more low frequency extension but the overall bass level will be lower than the midrange/treble (easy to model in any software).
The only time you could get an improvement is when something is wrong in the first place, eg - bass is peaky so you can tune lower or it's a sealed box, so you could possibly port them to gain more extension. Is the Lockwood a sealed box? Most Tannoys are designed for porting.
If it were me, i'd open the enclosure and find out what crossover it has (standard Tannoy or something Lockwood designed?). I don't know the model numbers but lets say the driver and crossover are for a York, then that's what i'd build.
Yes, the Lockwoods are sealed. It's a standard Tannoy HPD crossover.
John
Have a chat with Paul at RFC. I'm sure he could design something unique that fits your style, your room and optimises your HPDs.
Knowing Tom's and Adam's RFC designed cabinets I'm sure you would be delighted what Paul could do.
I know Paul has plans suitable for the 15" driver, I think they are called Warwick but I've never seen a photo of a pair. I will likely speak with him in due course but I wanted to gather as much info as I could before hand so I can better understand his advice. Don't want to waste too much of his time.
walpurgis
22-09-2018, 22:17
Where does the Amesbury fit in there Geoff, is that the proper name for the rectangular York?
No. I'd actually forgotten about the Amesbury (they were not in production very long). It fits between the York and Arden in lineage and is of similar dimensions. It was part of the first distinct series that housed HPD drivers (excluding the very last Chatsworths, which if I recall had HPD's and not Golds).
This comes from the K-series constructor guides from Tannoy.
Already shared this with John but may be of use to others;
For HPD 385 follow 3838 recommendation;
https://farm2.staticflickr.com/1950/31032917238_fe96676428_b.jpg
Obviously you'll need to adjust driver cut-out to suit.
https://farm2.staticflickr.com/1950/31032917238_fe96676428_b.jpg
Frank
Thanks Frank, favourite at the minute is a slight variation on II, an Arden sized cab which would sit on my stands. Probably 800 x 600 x 450 mm using 25mm plywood all round with a 500 x 500 sub baffle to give a recessed look to the driver and a bit more strength at the front. Should give a net volume of around 150L.
Is there any merit going for marine ply over hardwood ply?
My driver is rear mounted to the baffle in my current cabs so I’ll need a new gasket to go between the baffle and the rear of the driver for these new cabs, what’s best for this, industrial compressed paper gasket material or some sort of foam?
Thanks Frank, favourite at the minute is a slight variation on II, an Arden sized cab which would sit on my stands. Probably 800 x 600 x 450 mm using 25mm plywood all round with a 500 x 500 sub baffle to give a recessed look to the driver and a bit more strength at the front. Should give a net volume of around 150L.
Is there any merit going for marine ply over hardwood ply?
My driver is rear mounted to the baffle in my current cabs so I’ll need a new gasket to go between the baffle and the rear of the driver for these new cabs, what’s best for this, industrial compressed paper gasket material or some sort of foam?
This stuff is great;http://www.bluearan.co.uk/index.php?id=TUFFGAS20&browsemode=category
Baltic Birch would be my choice, and glue the driver cut out(s) to the rear panel(old JBL/Yamaha trick). If you can I'd go for the 165L, if not the porting will need a bit of adjustment.
Cheers for the gasket link.
Internal dimensions of II are 866x609x318mm=167.7L not sure where Tannoy got 175 from.
My 800x600x450 exterior gives 750x550x400 internal =165L so virtually identical.
I was reckoning on 150L net by the time you subtract a bit for the bracing and the driver basket, is that reasonable?
Cheers for the gasket link.
Internal dimensions of II are 866x609x318mm=167.7L not sure where Tannoy got 175 from.
My 800x600x450 exterior gives 750x550x400 internal =165L so virtually identical.
I was reckoning on 150L net by the time you subtract a bit for the bracing and the driver basket, is that reasonable?
Yeah 175 must be a typo, I got 165L by doing it quickly in my head. You should be fine.
Hi Frank,
Would Macca benefit from this, with the HPDs you sold him?:)
He still hasn't got any cabs sorted yet.
Marco.
Hi Frank,
Would Macca benefit from this, with the HPDs you sold him?:)
He still hasn't got any cabs sorted yet.
Marco.
Not really Marco. 3833/36, different drivers so not without different tuning.
Can’t be accused of rushing into this, a year and four months later!
Actually the Lockwoods have been sounding rather good of late following a bit of tinkering but I I spied this the other day and had a Baldrick moment.
27233
A bit of jiggery-pokery turned that into these. Idea is to spend as little as possible to see if it’s worth investing in a proper cabinet build. These are rough as but definitely serviceable. Tomorrow will see install of cross bracing, internal damping and maybe even get the mounting holes drilled and drivers fitted.
No idea why this photo is sideways. Really miss photobucket but there’s no way I’m handing out £90 a year or whatever it is.
27234
walpurgis
17-01-2020, 21:22
https://i.imgur.com/beWpL4v.png
Try using Imgur.
Just testing....
https://i.imgur.com/ruElxzs.jpg
Good solid 18mm plywood crate heading for the skip. Cut in half gives 2 nice sized 175L cabs.
Port dimensions are from this drawing, internal volume of cab is the same.
https://i.imgur.com/ytClgw7.gif
Hard work, but scotia PVAed in the corners will help.
Thanks Dennis, I have some 3/4” lath for that.
The frost is sitting thick on the cars in the driveway so I’m not overly inclined to go out to the garage just yet!
Bit parky here today, this is INSIDE the garage :eek:
https://i.imgur.com/WqMLUbh.jpg
All corner and edge bracing cut, glued and screwed in. The electric chop saw is the only way to go with this kind of work, I was able to get them just “so” for length that a gentle tap was required to fit them in, sweet! Glue and screws not totally necessary :)
https://i.imgur.com/ykeTQwY.jpg
Going to take the drivers out of the Lockwood cabs now and put them in the front baffles to get the holes marked for the mounting bolts.
Never tire of seeing these big drivers in the flesh, awesome. There’s a smell inside those Lockwood cabs that’s unique too, think it’s that horse hair type felt lining.
Yip, driver mounting PCD is 370mm as per Tannoy drawings, just checking.
Interestingly the cut out in the Lockwood baffle is only 295mm diameter. Wonder is that deliberate or a mistake. Sounds more like the size for the HPD315. Never noticed before, can’t see through the thick grill cloth.
Right, back to work.
Never tire of seeing these big drivers in the flesh, awesome. There’s a smell inside those Lockwood cabs that’s unique too, think it’s that horse hair type felt lining.
Yip, driver mounting PCD is 370mm as per Tannoy drawings, just checking.
Interestingly the cut out in the Lockwood baffle is only 295mm diameter. Wonder is that deliberate or a mistake. Sounds more like the size for the HPD315. Never noticed before, can’t see through the thick grill cloth.
Right, back to work.
If you use ample glue their is usually no need to use screws, and as it dries the water is absorbed into the wood pulling the mould into the corners, and the whole joint becomes very tight and solid.
Just back to these this evening.
Cross bracing fitted and driver mounting holes drilled in both cabinets.
If I find the bass too bloated I might staple some felt across that bracing like the aperiodic Lockwood Major cabinets and see what that’s like.
https://i.imgur.com/ixyRRm7.jpg
50mm glass mineral wool lining fitted. Just waiting for some gasket tape for the fronts.
https://i.imgur.com/fC7unPr.jpg
walpurgis
21-01-2020, 21:43
50mm glass mineral wool lining fitted
Hate that stuff, brings me out in rashes.
Hate that stuff, brings me out in rashes.
Agreed but this was very good, nowhere near as bad as the stuff you used to get.
It comes as very loosely packed 4’ x 2’ sheets which were easily worked compared to the rolls.
I did wear overalls, rubber gloves and a dust mask though!
https://www.homebase.co.uk/knauf-earthwool-omnifit-slab-50mm_p296296
Try these sites
http://www.44bx.com/tannoy/
http://www.44bx.com/tannoy/
The 385’s are 15” units and the Amesbury and Mansfield designs were in the same range as my Chatsworths whice have a 315 12” units I had mine fro new since 1975.
Try these sites
http://www.44bx.com/tannoy/
http://www.44bx.com/tannoy/
The 385’s are 15” units and the Amesbury and Mansfield designs were in the same range as my Chatsworths whice have a 315 12” units I had mine fro new since 1975.
Thanks Michael, already had a look at these sites.
Gasket tape fitted to both cabinets. Tomorrow night’s the night!
https://i.imgur.com/jP8dwI5.jpg
https://i.imgur.com/yBw3TrL.jpg
Well, we have sound!
Very early days but seems a more balanced sound, bass having an equal weight rather than a slight looking for it quality. Certainly more “relaxed” but then the Lockwoods were designed to be studio monitors.
I suspect the port will need tuning, it seems a bit “open”, just a little loose. I’ve stuffed a couple of cloths down one side of each port which has tightened things up a bit. Maybe lengthen it as per the plans that Frank posted and perhaps slightly reduce the overall aperture.
The big surprise is how the mids and top end seem a little more refined probably just due to the more even tonal balance. I’ve upped the energy setting from -1 to level.
https://i.imgur.com/4d1rHot.jpg
Looking good, I'd front mount the driver John.
Looking good, I'd front mount the driver John.
Thanks Frank and thanks for your help.
Will try front mounting, no gasket at the minute.
I take it it will sound different?
Not sure if this link will work....especially for Macca, some Diana Krall.
https://imgur.com/ch6EYbO
ToTo Man
24-01-2020, 10:59
You may wish to staple a piece of cloth over the rear of the port to contain the rockwool particles that may become airborne as air flows out of the port.
You may wish to staple a piece of cloth over the rear of the port to contain the rockwool particles that may become airborne as air flows out of the port.
The thought of all that glass fibre open to the room had crossed my mind, not good.
I hadn’t thought of putting a piece of something over the end of the port.
As these are very much prototypes and won’t around for too long, I hope, I think I’ll stick with it as is for now.
I’ll try blanking the port by 1/3rd then 2/3rds and see how it goes for bass response then perhaps lengthen it.
Sorry I didn’t fit 3 x 100mm circular ports.
Just use some grill cloth.. Bass will go right through it ok.. you can fit it on inside so its not seen
Just use some grill cloth.. Bass will go right through it ok.. you can fit it on inside so its not seen
ATC used fish net, I changed the mesh used in wedding veils.
Good ideas fellas, thanks. Still messing with port dimensions. All compromises!
Not sure if this link will work....especially for Macca, some Diana Krall.
https://imgur.com/ch6EYbO
:)
The thought of all that glass fibre open to the room had crossed my mind, not good.
I hadn’t thought of putting a piece of something over the end of the port.
As these are very much prototypes and won’t around for too long, I hope, I think I’ll stick with it as is for now.
I’ll try blanking the port by 1/3rd then 2/3rds and see how it goes for bass response then perhaps lengthen it.
Sorry I didn’t fit 3 x 100mm circular ports.
Hairspray is your friend.
Hairspray is your friend.
That’s a first :D
But it may seal off the port somewhat because it will glue strands together.
walpurgis
25-01-2020, 17:29
I think the idea may have been to use hairspray on the rockwool lagging to stop it shedding fibres. Not to use it on anything convering the port.
I'd be inclined to buy a fiver's worth of drinking straws to pack into the ports, to encourage laminar flow and reduce 'port chuffing'.
I think the idea may have been to use hairspray on the rockwool lagging to stop it shedding fibres. Not to use it on anything convering the port.
Exactly, it'll stop the lagging shedding fibres.
I think the idea may have been to use hairspray on the rockwool lagging to stop it shedding fibres. Not to use it on anything convering the port.
I'd be inclined to buy a fiver's worth of drinking straws to pack into the ports, to encourage laminar flow and reduce 'port chuffing'.
Yes, a better approach.
Firstly a big thanks to Edward for sending me some spare grill cloth he had from his a Radford monitor refurb completely FOC :champagne:
I’ve had these speakers every which way, full port, partial port, sealed, front mounted, rear mounted, you name it.
Having been used to these as sealed 110L Lockwood cabs going to 170L ported was quite a change. From needing an amp with low damping factor to get some bass to needing more control from the amp to keep things tight.
Bass reflex seems to be the best and natural state for this driver, it just sounds right. Better balanced, effortless and more efficient than sealed.
Front mounting the driver was surprising. The bass reduced slightly thankfully :eek: and the mids came much further out into the room, sounding even better after adding some extra polyester wadding on top of the fibreglass around the rear of the driver.
This is a BIG sound but bass was still slightly loose for my liking. I tried closing the port down a bit to tune it lower which tightened things up but the low bass made me queasy!
Having a lightbulb moment I put the big Luxman power amp into class A which increases the damping factor and I have to say in this configuration with the drivers front mounted and port fully open I got the best sound I’ve ever heard period from any system, it was MASSIVE, just a sheer wall of bruising force. I felt like hiding behind the chair, seriously, you couldn’t sit in the room with it. Beautifully balanced, tight bass, superb soundstage but in my 11x 13ft room it was a PA system.
After front mounting the drivers I knew the sound was too big for the room but I hung in there for the extra detail coming through but now with the amp cooking(literally) I had to give in so I’ve rear mounted the drivers again and sealed the ports up, phew, sighs...
A local dealer told me one time at a demo “you’re better looking for it than trying to run away from it”, now I understand.
So, what to do, I’m tempted to try a pair of Legacy Eatons or Stirling’s or maybe just leave the 385s in the sealed cabs, just seems a waste of big drivers. Sounds ridiculous I know but you need a big room for these things to be in proportion.
Front mounted driver awesomeness :D
https://i.imgur.com/S6dMjVN.jpg
fatmarley
04-02-2020, 08:54
Is that cabinet the correct width for those drivers/crossover? Just looks quite narrow for a large Tannoy. If the crossover has no baffle step correction because the drivers are supposed to be in wide baffles, but you put the drivers in narrow baffles, you'll get a dip in the lower midrange /upper bass.
I've had a quick go at modelling the drivers in your 170ltr box (172ltr is the nearest my software will allow). Light grey line is sealed, black is ported to 24hz and the dark grey line is a guess at room gain. What size room to you have, and is it a sealed room, or does it have openings? (openings affect room gain).
https://i.imgur.com/r0hyBG1.jpg
Hi Matt, thanks for taking the time to model the speakers.
Cabinet dimensions are 56x35x110cm external, 52x31.5x104 internal = 170L minus bracing and driver. What width of baffle would you recommend?
Room is sealed, 13x11ft with speakers on the short wall firing down the length of the room. Ceiling height is 8ft above speakers to middle of the room then tapers down at the listening end a bit.
Would you mind running the model for a 200L or 220L sealed box if you had the time as that's what I'm thinking of next?
Thanks!
fatmarley
04-02-2020, 12:34
I'm away from my pc for a couple of days but I will get on to it when I get back...
I'm away from my pc for a couple of days but I will get on to it when I get back...
Thanks Matt
Those look pretty close to the Arundel dimensions.
Arundel are amongst my favourite Tannoys.
Baffle step freq for;
Amesbury, York = 281hz,
Berkeley =325hz,
Arden= 260hz
Arundel=343hz
Johns =312hz.
Thanks Frank. They sound fantastic but too overpowering for this room. Would be wonderful in a bigger space.
ToTo Man
04-02-2020, 17:40
Interesting findings, JohnJo. Pity you don't have measuring gear as it would have been interesting to see the difference in frequency response between front-mounting vs rear-mounting. Perhaps flush-mounting would give you the best of both worlds?! ;)
What is it that you find too overpowering, the bass or just the entire presentation in general? Your listening space is quite small so it may be that you're sitting too close and receiving too much direct sound?
My room is 4.2m x 3.8m x 3.25m and I went from rear-mounted MG15s in sealed Lancaster cabs to rear-mounted MG15s in huge vented Lockwood Major cabs and it was as if the bass had been given a shot of steroids. I found it pressurised the room too much and made me nauseous when I positioned the cabs in my preferred spot (very close to the wall so as not to obstruct thoroughfare). The bass output below 100Hz was around +8dB higher with the Lockwoods than with the Lancasters. Moving my seat closer to the speakers helped to tame the bass but also resulted in more of a PA "in-your-face" type of sound, I suspect because I was now sitting too close to them! So I moved my seat backwards again and instead used EQ/DSP to reduce the bass and also iron-out a few problematic areas in the mids. This improved things enormously to the point that I could have happily lived with them after that. Sadly vanity got the better of me and I decided the Lockwood cabs weren't aesthetically 'pretty' enough so I let them go. I wish I'd tried them with the vents blocked off, - that was a missed opportunity.
PS - Nothing wrong with using your HPD385 in sealed enclosures if that's what you prefer. I could have happily lived with the amount and extension of bass from my MG15 in sealed Lancaster cabs. It was the colouration in the upper bass / lower midrange that made me want to try something else. I often wonder what an MG15 or HPD385 would sound like in a 75L-100L sealed, fully-inert, resonance-free enclosure.
DSP might well be worth a try, it's less hassle then building more cabs.
Richard, yes, once front mounted I felt I was sitting too close to the speakers, I wanted to back my chair up about 3 feet which I can’t do. Sound projected much further into the room. There was absolutely nothing wrong with any aspect of the sound, beautifully balanced but just too big, it’s hard to explain, it’s was uncomfortable in its scale. The big Luxman drove them fantastically in class A. I think sealed cabs is the way to go in this room but seems a terrible waste!
DSP might well be worth a try, it's less hassle then building more cabs.
Not really my style Martin, old school I guess.
ToTo Man
05-02-2020, 11:12
Those look pretty close to the Arundel dimensions.
Arundel are amongst my favourite Tannoys.
Baffle step freq for;
Amesbury, York = 281hz,
Berkeley =325hz,
Arden= 260hz
Arundel=343hz
Johns =312hz.
Should f3 calculations include the width of the cab sidewalls if they stand proud of the baffle? E.g. if I were calculating baffle step frequency for the Edinburgh cab do I include the width of the slotted mouldings as well?
If f3 = 115/Wb, that would make the Edinburgh's f3 = 174Hz, which is a fair bit lower than any of the above cabinets.
EDIT - Just checked again and I think my formula is wrong because the Arden is the same width as the Edinburgh (660mm) yet your f3 for the Arden is 260Hz?
fatmarley
05-02-2020, 12:26
If you want to know what the raw driver response looks like on your baffle, just download The Edge. Input your baffle width, height and driver size/position and it will show you what the frequency response looks like before the crossover does it's thing. I'd imagine it assumes a flat frequency response from 20hz to 20khz, so won't be a perfect representation.
Should f3 calculations include the width of the cab sidewalls if they stand proud of the baffle? E.g. if I were calculating baffle step frequency for the Edinburgh cab do I include the width of the slotted mouldings as well?
If f3 = 115/Wb, that would make the Edinburgh's f3 = 174Hz, which is a fair bit lower than any of the above cabinets.
EDIT - Just checked again and I think my formula is wrong because the Arden is the same width as the Edinburgh (660mm) yet your f3 for the Arden is 260Hz?
I'm wrong-it happens ;-)
Figures should be ;
York 191hz
Berkeley 216hz
Arden 174hz
Arundel 230hz
Johns 205hz
ToTo Man
05-02-2020, 18:23
I'm wrong-it happens ;-)
Figures should be ;
York 191hz
Berkeley 216hz
Arden 191hz
Arundel 230hz
Johns 205hz
Which implies my calculation is still wrong as I'm getting 174Hz for the Arden, based on a width of 660mm.
No Richard, I'd entered the DIY cab 'Arden equivalent' dimension of 600mm(now corrected). The f3 formula/principle holds though.
fatmarley
05-02-2020, 22:04
Hi Matt, thanks for taking the time to model the speakers.
Cabinet dimensions are 56x35x110cm external, 52x31.5x104 internal = 170L minus bracing and driver. What width of baffle would you recommend?
Room is sealed, 13x11ft with speakers on the short wall firing down the length of the room. Ceiling height is 8ft above speakers to middle of the room then tapers down at the listening end a bit.
Would you mind running the model for a 200L or 220L sealed box if you had the time as that's what I'm thinking of next?
Thanks!
Here's 210ltr sealed. It's almost exactly the same as 170ltr sealed, so not worth increasing volume. The dark grey line is with a guesstimate at your room gain with the dimensions you gave me.
https://i.imgur.com/XDMM3Cq.jpg
Here's another of your 170ltr ported to 24hz, but with a guesstimate at your room gain. It doesn't look good with that massive peak.
https://i.imgur.com/vpTwFhZ.jpg
What do you feel you are lacking? If you are lacking midbass punch then you'd need to reduce enclosure volume. That's the only way to increase it with a passive crossover.
Thanks Matt, that’s good info, as you say there appears to be little to gain from a larger sealed enclosure.
The port is tuned to around 40hz at present as far as I can tell from using the graphs in the constructors instructions.
Ported the speakers aren’t lacking anything but sound like a PA system scale wise in the room, they’re huge, not subtle. They’re much more more civilised as sealed, but would have liked a smidge more weight in the bottom end but it’s not a big issue.
The 170L cabs when sealed sound better balanced (deeper fuller bass) than the 110L cabs sealed.
fatmarley
05-02-2020, 22:42
Thanks Matt, that’s good info, as you say there appears to be little to gain from a larger sealed enclosure.
The port is tuned to around 40hz at present as far as I can tell from using the graphs in the constructors instructions.
Ported the speakers aren’t lacking anything but sound like a PA system scale wise in the room, they’re huge, not subtle. They’re much more more civilised as sealed, but would have liked a smidge more weight in the bottom end but it’s not a big issue.
The 170L cabs when sealed sound better balanced (deeper fuller bass) than the 110L cabs sealed.
Without measurements it's hard to say what's going on, but it may just be that sealed works better than anything else in your room.
I think you’re right. Looking at the trace with the room gain it’s not bad, pretty much what I’m hearing, a slight drop off in low frequencies. Thanks.
ToTo Man
06-02-2020, 10:43
No Richard, I'd entered the DIY cab 'Arden equivalent' dimension of 600mm(now corrected). The f3 formula/principle holds though.
Ah, ok Frank, that makes sense, thanks.
ToTo Man
06-02-2020, 10:58
I imagine the combination of 1) baffle step roll-off; 2) early LF roll-off from using too large an enclosure for the drive unit; 3) LF peak at port tuning; and d) room gain; can wreak quite a bit of havoc with the linearity of a speaker's in-room bass response, and that's before you even factor in peaks and nulls from room modes!...
Just a guess but the 'PA speaker in your face' description sounds like there is a big peak in output centered around 1KHz - essentially like giant Linn Kans.
I also have the issue of a sloping ceiling above my listening chair but we’ll get there, it’s only HIFI, there’s people with bigger problems :)
Ah, ok Frank, that makes sense, thanks.
The original post gave the +6 dB frequency
OK, next step with the sealed cabs is amp with lower damping factor for fuller bass.....
https://i.imgur.com/2xHzpJf.jpg
Not much puff with the passive preamp so out comes the active....
https://i.imgur.com/NADv4To.jpg
Interesting to observe how the larger Tannoy systems Baffle Step freq sits below the average room Schroeder frequency. I'd guess this is why they don't bother with BSC.
darkmatter
13-06-2021, 10:31
@fatmarley
Could you tell me what simulation programme was used here?
Thanks
DM :)
Here's 210ltr sealed. It's almost exactly the same as 170ltr sealed, so not worth increasing volume. The dark grey line is with a guesstimate at your room gain with the dimensions you gave me.
https://i.imgur.com/XDMM3Cq.jpg
daveskis
26-08-2021, 22:24
A challenge but a fantastic project to have completed. The sound of these will blow you away JohnJo.
https://theartofsound.net/forum/showthread.php?12023-Westminsters
Beautiful work David :stalks:
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