Cabinet Plans for Tannoy HPD 385

[JohnJo]

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

Thanks Matt

[cooky]

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.

[JohnJo]

Thanks Frank. They sound fantastic but too overpowering for this room. Would be wonderful in a bigger space.

[ToTo Man]

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.

[Macca]

DSP might well be worth a try, it's less hassle then building more cabs.

[JohnJo]

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!

[JohnJo]

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]

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]

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.

[cooky]

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