Why commercial OB are expensive?

[thewanderer]

First apologies if the question is obvious or dumb . I am trying to evaluate open baffles as option. Options seems to be at two extremes. Either I buy driver like from lii audio and go for DIY something I can dare to do even with bare minimum skills or I have to consider offerings from pure audio, spatial audio which are relatively expensive compared to boxed speakers.

I was wondering is there anything inherently expensive to get open baffles right or build or need superior know-how's of to build them? Or is it just due to number of volumes they sell it tends to get expensive?

 

[Cable Monkey]

It is a niche market. Small volumes sold to enthusiasts who prefer the OB format but don't wish to build their own.

 

[Non-Smoking Man]

One thing that is good about open baffle speaker systems is that you can use big bass drivers.

You can't beat size when it comes to bass - big drivers move air much more easily and with less distortion than smaller drivers because the cones have to move less for the same SPL. (More cone movement = more distortion.)

Ive just paid £230 for a pair of used JBL 2241 18" sub bass drivers that are in good condition and will go in some folded horn cabs. So the used market is your friend.

The next advantage is also cost related - the majority of the cost of big speakers is the cabinet. Clearly there are savings to be had with OBs.

A possible drawback in use is that they are dipoles i.e., they radiate forwards and backwards. This makes siting the speaker in the room of importance.

I have a pair of OB dual concentric 18" drivers that I can start you off with. They have a 1" driver firing through the middle of the main cone. Arguably its all you would need to start you off. (Depending on where you are I could deliver them. PM me i9f interested.)
Jack NSM

 

[thewanderer]

One thing that is good about open baffle speaker systems is that you can use big bass drivers.

You can't beat size when it comes to bass - big drivers move air much more easily and with less distortion than smaller drivers because the cones have to move less for the same SPL. (More cone movement = more distortion.)

Thanks. I did not realize that, irrespective of the cost big bass drivers certainly is big unique advantage

I have a pair of OB dual concentric 18" drivers that I can start you off with. They have a 1" driver firing through the middle of the main cone. Arguably its all you would need to start you off. (Depending on where you are I could deliver them. PM me i9f interested.)
Jack NSM

Thanks for the suggestion, would have loved to consider it, unfortunately i don't live in UK

 

[Psilonaught]

I'd like to try a large OB active setup one day, see how they compare to my magnepans.

Something like these 👌

 

[bencat]

I know that many are going to roll their eyes as I get on my favourite hobby horse but I have to ask the question anyway . Would I be correct in thinking that one way to go about getting an open baffle set up to work correctly and musically in a room would be using active / DSP to control thing ? Firstly this would enable the amplifiers to best control the drivers and keep them tightly working within their best working parameters and not being stressed in crossover areas . Secondly as noted being a natural dipole something like DIRAC Live would be able to control and filter out much of the back reverb you get . Also the echoes from reflection . I would love to try this with a sensible three way say 15 -18 for Bass , 8 -10 for Mid and then a sensible tweeter (all inches for driver sizes) would this be sensible or would you need four drivers ?

Also given my very limited mechanical skills are there designs for the frame out there that could be taken to a workshop and be made up ?

 

[MF 1000]

As I recall a Wammer on here exhibited a pair at the last Scalford that had two 18” drivers each side for bass, 10 “ mid bass etc …..they were 7 ft tall In a custom made alloy curved frame setup

DSP wasnt used and they didn’t perform ….well to my ears as good as they could etc

Not sure what happened to them.

Drewan, who hasn’t posted in a long time had an open baffle setup using two DSQ units but ran a ‘std’ subwoofer (Miller & Chrysle) fir the bottom end. Sounded like you were sat inside a pair of headphones but was very directional

 

[hearhere]

If the OP cares to read about Open Baffle speaker design, he can't do much better than the words of Gilbert Briggs, founder of Wharfedale. His company used to build OB speakers way back and included descriptions of the pros and cons in his book “Loudspeakers”, with practical drawings in “Cabinet Handbook”. There's a whole chapter on the subject, but if I remember correctly one of the big problems is controlling the distance the cone is allowed to travel. With box designs, the enclosed air behind the driver limits this movement so that the coil remains within the magnet's influence. Without this cone movement control, the cone easily moves beyond its design movement limits and distortion or even damage occurs. A "flabby" sound results with poor definition of bass detail.

Also the baffle itself has to be incredibly rigid as it has none of the support and bracing that a box design offers; and a baffle that's prone to vibration becomes an unwanted noise generator in its own right at the same time as adversely affecting the (already compromised) sound from the driver.

It’s a DIYers dream that the OB design will make building a speaker very much easier – but in practice, possibly the reverse is true and unless you know EXACTLY how the physics works and EXACTLY which driver may be suitable, it’s probably best to follow the more conventional box design.

 

[thewanderer]

If the OP cares to read about Open Baffle speaker design, he can't do much better than the words of Gilbert Briggs, founder of Wharfedale. His company used to build OB speakers way back and included descriptions of the pros and cons in his book “Loudspeakers”, with practical drawings in “Cabinet Handbook”. There's a whole chapter on the subject, but if I remember correctly one of the big problems is controlling the distance the cone is allowed to travel. With box designs, the enclosed air behind the driver limits this movement so that the coil remains within the magnet's influence. Without this cone movement control, the cone easily moves beyond its design movement limits and distortion or even damage occurs. A "flabby" sound results with poor definition of bass detail.

Also the baffle itself has to be incredibly rigid as it has none of the support and bracing that a box design offers; and a baffle that's prone to vibration becomes an unwanted noise generator in its own right at the same time as adversely affecting the (already compromised) sound from the driver.

thanks for great insights and suggestion on Gilbert Briggs. Will certainly read it.

 

[Psilonaught]

If the OP cares to read about Open Baffle speaker design, he can't do much better than the words of Gilbert Briggs, founder of Wharfedale. His company used to build OB speakers way back and included descriptions of the pros and cons in his book “Loudspeakers”, with practical drawings in “Cabinet Handbook”. There's a whole chapter on the subject, but if I remember correctly one of the big problems is controlling the distance the cone is allowed to travel. With box designs, the enclosed air behind the driver limits this movement so that the coil remains within the magnet's influence. Without this cone movement control, the cone easily moves beyond its design movement limits and distortion or even damage occurs. A "flabby" sound results with poor definition of bass detail.

Also the baffle itself has to be incredibly rigid as it has none of the support and bracing that a box design offers; and a baffle that's prone to vibration becomes an unwanted noise generator in its own right at the same time as adversely affecting the (already compromised) sound from the driver.

It’s a DIYers dream that the OB design will make building a speaker very much easier – but in practice, possibly the reverse is true and unless you know EXACTLY how the physics works and EXACTLY which driver may be suitable, it’s probably best to follow the more conventional box design.

Or just buy some proper open baffle speakers like Magnepan 😂

Putting a cone inside a box isn't the answer to cone based OB flaws.

 

[TheFlash]

As I recall a Wammer on here exhibited a pair at the last Scalford that had two 18” drivers each side for bass, 10 “ mid bass etc …..they were 7 ft tall In a custom made alloy curved frame setup

DSP wasnt used and they didn’t perform ….well to my ears as good as they could etc

Not sure what happened to them.

Drewan, who hasn’t posted in a long time had an open baffle setup using two DSQ units but ran a ‘std’ subwoofer (Miller & Chrysle) fir the bottom end. Sounded like you were sat inside a pair of headphones but was very directional

I'm not sure whether I'm thinking of the same setup but I'm afraid I settled down to hear one quite visually striking and obviously open baffle system at that same show and had to leave as soon as was polite (ok, possibly slightly before... I think I lasted less than a minute).

 

[bencat]

Thanks for the info Keith I visited Drewan very early on in my active start days and heard his system and as you say given the size of the speakers and how close you were to them it was indeed like listening to headphones but with real physical bass.

What I am interested in is can you get the cr smooth enough with three drivers or are you asking one driver to do too much .

 

[MF 1000]

obv I’m not open baffle but it’s why I went 4 way with amps tailored to the frequency range of each driver

 

[MF 1000]

I'm not sure whether I'm thinking of the same setup but I'm afraid I settled down to hear one quite visually striking and obviously open baffle system at that same show and had to leave as soon as was polite (ok, possibly slightly before... I think I lasted less than a minute).

I found the thread on them

https://www.hifiwigwam.com/forum/th...ital-active-crossovers-dsp-amp-room-eq.73230/

seems like they did have DSP ……I still didn’t rate them esp fir the cost too

 

[steve 57]

I found the thread on them

https://www.hifiwigwam.com/forum/th...ital-active-crossovers-dsp-amp-room-eq.73230/

seems like they did have DSP ……I still didn’t rate them esp fir the cost too

Nice to read that Keith, but it still makes me chuckle when anyone describes anything in hifi as 'end game'.

 

[JamieMcC]

First apologies if the question is obvious or dumb . I am trying to evaluate open baffles as option. Options seems to be at two extremes. Either I buy driver like from lii audio and go for DIY something I can dare to do even with bare minimum skills or I have to consider offerings from pure audio, spatial audio which are relatively expensive compared to boxed speakers.

I was wondering is there anything inherently expensive to get open baffles right or build or need superior know-how's of to build them? Or is it just due to number of volumes they sell it tends to get expensive?

Have a look at the OB15 from Troels Gravesen

http://www.troelsgravesen.dk/OBL-15.htm
From my own experience I think you can get a lot of bang for your buck going the DIY route with OB's the major draw backs are
to achieve best results they tend to be physically large and require a good amount of space in the room. Foot prints and size can be reduced with downward slot loaded bass drivers Google Nelson Pass slot loaded speaker or Nelson Pass SLOB Google should pull up some pics and videos.

Baffle size can potentially be reduced perhaps if you have a large flat screen TV that would act like a baffle wing if positioned between the speakers.

Further reading.

https://www.diyaudio.com/community/threads/pass-slob-build-discussion.300952/
There is a lot of info out there just takes a bit of time to research find and filter out what might work best for you.