Open Baffle Speaker With Active Bass

[greenhomeelectronics]

Wow, nice looking job. There is nothing more satisfying than building a pair of speakers that sound just right in your environment. If you are looking for material to replace the towel you might like to try some stuff called sorbo - it's a very dense foam rubber type substance that has excellent absorbtion characteristics, I have used it myself many times.
Dave.

[Marco]

You know of course they won't

Notice I said most box speakers. There's no way a 12 inch driver on an open baffle will hit the chest like a 12 inch driver in a box will. Laws of physics innit? I'd probably need a pair of 15s to get anywhere near.

You're welcome to have a go with your amp but we need to remember that these things are efficient, so the power handling is not that of a modern driver. The volume must be kept down so your proposed experiment is really a non-starter. The Goodmans Axiom 401 will only take 15W before it blows up and I love these drivers too much to risk them in any way. Also they are not mine (not yet anyway )

The Fostex FE108EZ driver is nominally an 8W max power speaker with a 0.28mm xMax and again I'm not prepared to risk destroying them in a power game.

I'm not trying to be awkward or anything Marco, but you can see the problem.

Hey, Steve, no worries mate. I completely understand

However, for that reason you can probably appreciate exactly why I don't use open baffles and SET amps!

Marco.

[SteveTheShadow]

Wow, nice looking job. There is nothing more satisfying than building a pair of speakers that sound just right in your environment. If you are looking for material to replace the towel you might like to try some stuff called sorbo - it's a very dense foam rubber type substance that has excellent absorption characteristics, I have used it myself many times.
Dave.

Thanks Dave I'll certainly look into that.

No probs Marco

Steve

[SPS]

Hi Steve,

Nice speakers, btw!

Much as I like good open baffles (and there's plenty to admire in their presentation) the ones I've heard so far (at Owston, etc) lack the sort of scale and visceral bass I get with my Spendor SP100s (with 12" bass units) when playing music at the sort of silly loud levels I do when friends pop round. It's that gut-wrenching, feel it in your chest, 'physical' quality to the bass that I miss with the open baffles I've heard so far, and I want that, big time!

I find almost every other aspect about the presentation of open baffles better than large well-sorted box speakers (and otherwise), apart from the above. I also find much the same thing with good push-pull amps compared to SETs, but that's for another discussion.

Like always though, I'm always open-minded about these things and if or when I hear a pair of open baffles which do the 'visceral' thing in the bass that I like I'll openly acknowledge it!

If you're bringing your speakers to Owston this weekend then I'll bring my p/p 30W Class A Copper amp and some suitable music to see whether your babies do it for me in the bass and scale department

Marco.

Interesting points Marco

i would have agreed with you a couple of years ago

the bass is one of the real weak points with most home audio speakers

there is no way to get really clean bass from a box, with every type of speaker there are trade offs to some extent..

but less so in the sound deptment, if the low bass can be achieved with a baffle

it would be great if you could get your spendors in the car too..

as you know the only way is to a/b..

if your playing at loud levels say 109 dbs.. you need to be using say around 60watts.. if you are getting those levels from your existing amp you will be well into clipping.. so you will have fair bit of distortion going on.. and probably not getting the 'scale' as much as you think.. as its the peaks that clip.

with high watts into speakers like that, the voice coils will be getting very warm causing further clipping..
add to that the port output .. which is with bass reflex is slightly delayed to avoid the low notes being cancelled, and to achieve reasonable levels from the single bass driver...this is not accurate bass.. but one easily get used to the sound of it..

all the above has the effect of thickening the sound.. giving it more body.... more than it should have ? .. and of course, masks some of the finer details

the real advantage of high eff is that one can get those sound levels with 4 or 5 watts, all class A, no feed back, triodes
and the voice coils are are not being warmed up too much..
and scale...the sound is clean.

steve has a few trade offs.. the main one with smaller baffles is that he's using subs.. for the very low bass only.. and only below 60 hz

steve

[Filterlab]

Steve, I love your speakers and I bet they sound superb. The sound from an open baffle arrangement is so liberating and airy, although I'm partial to the thump from a speaker with a small enclosure as well. However experience from using electrostats has taught me a lot about choosing speakers to suit the music one listens to the most, and these sound like they're exactly right for their purpose. That's pretty well the reason I sold my electrostats and went back to stand mount speakers, they're exactly right for me.

However, tastes change over the years and I may well look into open baffle speakers in the future.

Excellent work, they look gorgeous and the idea of combining a bass enclosure with the open baffle arrangement is something that captures the best of both worlds, much like the hybrid electrostats. Lovely stuff.

[Marco]

Hi Steve,

the bass is one of the real weak points with most home audio speakers

there is no way to get really clean bass from a box, with every type of speaker there are trade offs to some extent..

I completely agree. Hi-fi is all about choosing your compromises and the Spendors are by no means perfect - there is no such thing as a perfect loudspeaker. However they get the important things right (for me); it's not just about realistic, tightly controlled, musical sounding bass, which they do extremely well, but also the way music is communicated overall via other parts of the frequency range. The Spendors give great insight into music and have clarity and definition without any fatigue factor whatsoever.

Open baffles sound absolutely fantastic in the midrange with a 'freedom' and expressiveness that no box speaker can match - I love that about them - but I've yet to hear a pair that can do deep, 'visceral' bass in the way of a large box speaker; and there is very little coloration, believe me, when you get it right. There's no audible distortion, clipping, or thickening of the sound whatsoever in my system when music is played within the capabilities of the amplifier and speakers - and you have to go some to exceed that level! You must come round and visit sometime

A friend of mine has recently bought a pair of (huge) 96db Tannoy Canterburys with 15" dual-concentric drivers and the sheer scale that these produce with his 40w p/p valve amp is frightening. Your ears will give in long before they do! That's the way I like it as I couldn't be bothered worrying about blowing drive units, etc, as seems to be the case with open baffles. And SET amps, as lovely as they sound, are too 'weedy' for me. All the guys at Owston seem forever to be worrying about the volume music is played at, as there appears to be a finite level of loudness one can achieve before things go pop. That's just not my 'thang'. I go to a fair few gigs throughout the year and I can tell you that Ian's Tannoys produce a sound that's as near as I've heard to live music, which is where it's at for me with hi-fi, and I'm sorry, a world apart from what I've heard so far from any open baffle design and SET amp.

These are just my honest observations to date. Feel free to convince me differently at Owston!

Marco.

[John]

I would think steves listening room is about 4x4m.. so would not be put off too much, the real issue for many is can you accept the size of the speakers in the room,
open baffles can be very good ..i have not heard the bastinis but i would guess they would have a similar sound to steve's and my own..

steve

Thanks for the info its good to know that open baffle can work in my room, at the moment I use Wharfedale Opus 3 lovelly speakers abd really big

[SPS]

Hi Steve,



I completely agree. Hi-fi is all about choosing your compromises and the Spendors are by no means perfect - there is no such thing as a perfect loudspeaker. However they get the important things right (for me); it's not just about realistic, tightly controlled, musical sounding bass, which they do extremely well, but also the way music is communicated overall via other parts of the frequency range. The Spendors give great insight into music and have clarity and definition without any fatigue factor whatsoever.

Open baffles sound absolutely fantastic in the midrange with a 'freedom' and expressiveness that no box speaker can match - I love that about them - but I've yet to hear a pair that can do deep, 'visceral' bass in the way of a large box speaker; and there is very little coloration, believe me, when you get it right. There's no audible distortion, clipping, or thickening of the sound whatsoever in my system when music is played within the capabilities of the amplifier and speakers - and you have to go some to exceed that level! You must come round and visit sometime

A friend of mine has recently bought a pair of (huge) 96db Tannoy Canterburys with 15" dual-concentric drivers and the sheer scale that these produce with his 40w p/p valve amp is frightening. Your ears will give in long before they do! That's the way I like it as I couldn't be bothered worrying about blowing drive units, etc, as seems to be the case with open baffles. And SET amps, as lovely as they sound, are too 'weedy' for me. All the guys at Owston seem forever to be worrying about the volume music is played at, as there appears to be a finite level of loudness one can achieve before things go pop. That's just not my 'thang'. I go to a fair few gigs throughout the year and I can tell you that Ian's Tannoys produce a sound that's as near as I've heard to live music, which is where it's at for me with hi-fi, and I'm sorry, a world apart from what I've heard so far from any open baffle design and SET amp.

These are just my honest observations to date. Feel free to convince me differently at Owston!

Marco.

to be honest Marco, i had heard open baffles quite a few times at various meets, and was never convinced.. i liked my big lowther horns..

It was not until Nick brought his baffles around to my house about 2 years ago now.. and we did a lot of a/b testing, then i heard the difference in the bass..
once i started to reconised what Nick had been pointing out to me .. my view of boxed speakers changed..

the Se / push pull thing is a matter of opinion, there are very good examples of each type..
the speakers you own or use, dictate how many watts you need.

I would love listen to your kit at your place..we'll speak at the weekend and try to arrange something?

I have no worrys about blowing drive units and will happily crank mine up
i could get 120db peaks from 5 watts of px25 but is was not as clean as it could be with the old horns,
The baffles give about another 3 dbs due to the doubling up of the drivers
but much cleaner in the bass..

with open baffles there is no load from a box or horn.. so you have to keep well in the rated wattage.. but there's the advantage of the fact that there is less compression or expansion from the box to deal with for the driver..
Briggs in the 50's documented these effects in his books

last time at owston I had fitted a new driver the day before the meet, so was taking things steady in the room... and i was only using a 2 watt amp most of the time

I'll be bring the other amp only this time it makes about 3 watts or so so we can really blast it...
the valves in it now are real vintage stuff.. very different from last time..


steve

[Marco]

Sounds great, Steve! I'll look forward to it

Owston is always good because apart from the social aspect you always come away having learnt something.

Marco.

[Cotlake]

Sounds great, Steve! I'll look forward to it

Owston is always good because apart from the social aspect you always come away having learnt something.

Marco.

Yes I agree, and it is especially pertinent when the listening environment is very compromised. I'm sure a listen to O/B speakers with a low wattage SE amp is a very different and fulfilling experience in the domestic situation. Organising small minifests is the way to trial properly really. The big events however as so much fun in all aspects. Looking forward to seeing y'all (trying to be topical ) at the weekend.

Best wishes,

Greg