Cabinet Plans for Tannoy HPD 385

[JohnJo]

Hairspray is your friend.

That’s a first

[Pharos]

But it may seal off the port somewhat because it will glue strands together.

[walpurgis]

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'.

[cooky]

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.

[Pharos]

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.

[JohnJo]

Firstly a big thanks to Edward for sending me some spare grill cloth he had from his a Radford monitor refurb completely FOC

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 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.

[JohnJo]

Front mounted driver awesomeness

[fatmarley]

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).

[JohnJo]

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]

I'm away from my pc for a couple of days but I will get on to it when I get back...