Open Baffle Scanspeak 15w8530

[george a]

Hi All

I'm currently trialing some new ribbons i've recently constructed (500hz or so and upwards) , with a view to go either open baffle or closed back (better imaging so far..)

However i'm currently using a Scanspeak 15w8530 as a mid from 90hz to 500hz in an enclosure .
I can't but help wonder how the Scans would go in an open baffle

Does anybody have experience / knowledge / comment in this suggestion.

System is triamped via a DCX2496 with 48db/oct slopes available to control Low frequency excursion on the scans.

System also has a peerless sub in a reflex enclosure.

at the moment in its cobbled together fashion the system sounds magnificent - especially the ribbon which replace vifa xt25's (which I could never get to sound "right")

Any comments appreciated.

Cheers and thanks.

[5th element]

It all depends on how loud you want it to go really. To get the most out of the 15W you'd need to keep it on a fairly narrow baffle, this will increase the amount of EQ necessary to keep the low end up. Going down to ~100hz is possible but you cannot beat the laws of physics so the max SPL will be limited. You can of course increase the baffle width at the expense of response smoothness to get more low end output.

As the xover is active and DSP based it will make it a breeze to modify. Personally I'd say give it a go, make yourself a test 'cabinet' and see if they will work (this shouldn't be too hard really as it's just a baffle with legs). Do remember you need ample space behind the speakers though.

[a_tewinkel]

Originally Posted by 5th element

It all depends on how loud you want it to go really. To get the most out of the 15W you'd need to keep it on a fairly narrow baffle, this will increase the amount of EQ necessary to keep the low end up. Going down to ~100hz is possible but you cannot beat the laws of physics so the max SPL will be limited. You can of course increase the baffle width at the expense of response smoothness to get more low end output.

As the xover is active and DSP based it will make it a breeze to modify. Personally I'd say give it a go, make yourself a test 'cabinet' and see if they will work (this shouldn't be too hard really as it's just a baffle with legs). Do remember you need ample space behind the speakers though.

A 5,5" driver cannot reach 100 Hz in an open baffle, only at whispering levels. I'd apply a baffle with a width of at most 8" and try to push it down to 200 Hz. Try a calculation with this spreadsheet: http://www.linkwitzlab.com/spl_max1.xls

[george a]

Hi All thanks for the replies
I think the point raised by a_tewinkel kills it - whisper volume - not really enough - Oh well
Thanks for your efforts any way

Cheers

[a_tewinkel]

I've done a quick calculation, it would do about 83 dB @ 100 Hz (101 dB @ 200 Hz). I'm not sure what levels you listen at, but personally I'd consider everything that will do less than 95 dB not usable.

I've run an 8" woofer down to 50 Hz in an open baffle which could also reach about 80 dB if I remember correctly. It had to work very hard, even for low volumes. It now has a 120 Hz cut-off and now overheating is sort of a problem when I turn it up.

[5th element]

83dB is more then use-able in my opinion and is actually quite loud! I thought the point was to experiment and see if you like the sound of the open baffle. Then if you do you can expand the system to remove some of those limitations.

[a_tewinkel]

Originally Posted by 5th element

83dB is more then use-able in my opinion and is actually quite loud! I thought the point was to experiment and see if you like the sound of the open baffle. Then if you do you can expand the system to remove some of those limitations.

As an experiment, why not indeed. 83 dB is indeed loud, but if you consider that most music has peaks of 10-20 dB above the average level (sometimes even more), then I would consider it insufficient.

[5th element]

People always talk about these peaks. When I talk about 83dB being loud, I am talking about 83dB representing digital zero where it cannot go any louder. In other words 83dB = the maximum peak level. If you play modern, reasonably compressed music through such a system it will sound loud, of course there probably isn't a huge amount of difference between the average and peak levels, but loud it will sound. More of my music collection is tailored in this direction and in my room ~83dB from each loudspeaker on modern music is loud enough for 90% of my listening.

For classical music 83dB on the peaks is simply out of the question though as the average level on the majority of recordings would be way too far down to be enjoyable and hence you need to turn it up. This of course sets the peaks higher and higher, where yes, you would need peak capabilities approaching 100dB+ I'd reckon for things to remain convincing. (When I listen to classical I want my peaks to hit into the hundreds otherwise it sounds unconvincing).

[a_tewinkel]

That's spot on. If you only listen to highly compressed pop, this is hardly a problem. I do listen to classical, live and other sorts of dynamic music, however

So I guess you're right that it's up to the TS to try and find out if this will fit his tastes.