Bowers & Wilkins mount their tweeter assembly above the cabinet - supposedly it's more acoustically decoupled and cleaner in its solid enclosure. See pic below.
Are there any benefits to mounting a tweeter above the cabinet in a similar way, like in a heavy aluminium tube? The main cabinet for a 2-way could have the mid-bass mounted right at the top so as to be as close to the tweeter as possible.
One benefit would be that you could easily swap tweeters when experimenting.
Are there any benefits to mounting a tweeter above the cabinet in a similar way, like in a heavy aluminium tube? The main cabinet for a 2-way could have the mid-bass mounted right at the top so as to be as close to the tweeter as possible.
One benefit would be that you could easily swap tweeters when experimenting.
Yes. You don't have to lift the tweeter & associated support parts at the same time as the woofer & cabinet. The tweeter doesn't do bass reflex with the cabinet, it is just mounted in there to make the sale.
I have my speakers mounted 5' off the ground to project voice & other mid frequencies over the piano.organ, couches and coffee table in my music room. Each weighs 72 lb and I can no longer lift that much to shoulder level to put them on the stands. For 2 years after I bought them the lowest estimate I got for putting them up was $350. Moving agency, 2 men and a truck, minimum 3 hours. After 2 years I found an unemployed person that would do it for $60. Finally.
My tweeter + horn weighs about 5 lb, and the crossover components are another 3. Shrinking the cabinet size could cut off another 5 lb. 50 lb is just about doable. I could put the crossover components next to the amp behind the record rack. The woofer needs 12 ga or thicker wire, but the tweeter can be run with 16 ga zip cord. It only draws 70 w when the speaker is sounding off at 500 w AES pink noise.
Locating the tweeter accurately to the woofer would be a requirement for known lobe results. That need not weigh more than a pound.
For some comparison, look at the Asathor thread. With 3/4 plywood and internal bracing, I imagine that speaker weighs 70 lb or more.
If you like actual bass, a 15" 2 way gives low distortion with the woofer only moving 0.5 mm at music room levels. CD on a horn are another low distortion feature. My SP2(2004) are -3db 54 hz, -10 db 40 hz. With them backed up to a plaster wall for the 3 db half space boost, no sub channel is required to listen to organ and piano music. I'm building ugly clones, since the last pair (SP2-XT) were carried off to a pawn shop or fence by a burglar. No I don't stay home all the time watching everything. That Peavey logo ensures a reasonable cash return. My clones will be ugly unvarnished MDF; would be worth more quick cash pulling out the woofers & selling them separately. That is work, which burglars are not known for. The guy that got my sound equipment, stole every driver I owned including two spare RX22 CDs on horns, and the 6.5" whizzer cones in cardboard boxes I salvaged from projection TV's on the curb. He did not steal the four 15" drivers mounted in organs.
I have my speakers mounted 5' off the ground to project voice & other mid frequencies over the piano.organ, couches and coffee table in my music room. Each weighs 72 lb and I can no longer lift that much to shoulder level to put them on the stands. For 2 years after I bought them the lowest estimate I got for putting them up was $350. Moving agency, 2 men and a truck, minimum 3 hours. After 2 years I found an unemployed person that would do it for $60. Finally.
My tweeter + horn weighs about 5 lb, and the crossover components are another 3. Shrinking the cabinet size could cut off another 5 lb. 50 lb is just about doable. I could put the crossover components next to the amp behind the record rack. The woofer needs 12 ga or thicker wire, but the tweeter can be run with 16 ga zip cord. It only draws 70 w when the speaker is sounding off at 500 w AES pink noise.
Locating the tweeter accurately to the woofer would be a requirement for known lobe results. That need not weigh more than a pound.
For some comparison, look at the Asathor thread. With 3/4 plywood and internal bracing, I imagine that speaker weighs 70 lb or more.
If you like actual bass, a 15" 2 way gives low distortion with the woofer only moving 0.5 mm at music room levels. CD on a horn are another low distortion feature. My SP2(2004) are -3db 54 hz, -10 db 40 hz. With them backed up to a plaster wall for the 3 db half space boost, no sub channel is required to listen to organ and piano music. I'm building ugly clones, since the last pair (SP2-XT) were carried off to a pawn shop or fence by a burglar. No I don't stay home all the time watching everything. That Peavey logo ensures a reasonable cash return. My clones will be ugly unvarnished MDF; would be worth more quick cash pulling out the woofers & selling them separately. That is work, which burglars are not known for. The guy that got my sound equipment, stole every driver I owned including two spare RX22 CDs on horns, and the 6.5" whizzer cones in cardboard boxes I salvaged from projection TV's on the curb. He did not steal the four 15" drivers mounted in organs.
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There are advantages to making the baffle around the tweeter as small as possible. Many well-regarded speaker designs do this, such as rockport. The B&W approach is to use no baffle at all.
Interesting post about the weight of cabinets! I'd be going for a 2-way, not too heavy.
One thing I was wondering was whether you'd want the tweeter in an aluminium tube so there was no front baffle around it, or mounted on an aluminium baffle that was an extension of the front baffle and the same width.
B&W used a slim tube, which is what hifijim suggests. I looked up Rockport and the tweeter is on the front baffle as usual, though it's sculpted to be thin as possible.
So far looks like it's a good idea to mount the tweeter on top. I guess the convention of putting it on the front baffle above the mid-bass is just for convenience - to get everything into one box. Safer to ship that way. Visually I think tweeter on top looks pretty cool - I like it.
One thing I was wondering was whether you'd want the tweeter in an aluminium tube so there was no front baffle around it, or mounted on an aluminium baffle that was an extension of the front baffle and the same width.
B&W used a slim tube, which is what hifijim suggests. I looked up Rockport and the tweeter is on the front baffle as usual, though it's sculpted to be thin as possible.
So far looks like it's a good idea to mount the tweeter on top. I guess the convention of putting it on the front baffle above the mid-bass is just for convenience - to get everything into one box. Safer to ship that way. Visually I think tweeter on top looks pretty cool - I like it.
Many tweeters are designed into half-space and intended to be mounted onto a baffle. It would take a special tweeter to work ideally in a tube. Even then you have a large directivity transition, not my cup of tea.
Ah, OK, so a vote for continuing the baffle upwards from AllenB. The tweeter can still be on top of the cabinet but on a baffle the same width. This could be made from e.g. an aluminium plate rather than wood. In fact the mid-bass and tweeter could both be mounted on the same aluminium plate like 4mm/5mm, and that then bolted on the front of the cabinet. The tweeter part would extend above the top of the cabinet.
Any more votes for keeping the tweeter on the same baffle?
Any more votes for keeping the tweeter on the same baffle?
A tweeter could be fitted in a same-width enclosure like Focal does, again on top of the main cabinet.
The existence of problematic diffraction doesn't necessarily result in significant variations in response, but many focus on response and polar response in an attempt to make that determination.
Also, I'm trying to decide whether this plot is symmetrical above and below the 0 degree line. It shouldn't be...
Also, I'm trying to decide whether this plot is symmetrical above and below the 0 degree line. It shouldn't be...
Attachments
The Bowers & Wilkins looks like a
possible large back chamber. To achieve a driver
with low resonant frequency.
Which can be crossed low. Just reminds me of
the Swan designs around 2000 where they just
top mounted a large chamber tweeter.
Apply mystical magical sales speech to further
induce excitement.
You can get a TN28 driver for 20 bucks these days
Likely if you just became acquainted with common
diffraction modeling. Most of the mysterious and getting
a better understanding of why tweeters are mounted in
numerous locations. Will become more visually
easier to grasp
Make more sense when trying to match
specific drivers at a specific crossover point.
many work with 2k 3k or 4k points in a very generalized
manner with common textile domes.
But once pushing to 1k or lower your dealing with
a specific tweeter and likely larger back chambers.
Or larger baffles or waveguides.
Basically in all simplicity a lower resonate frequency
or combination of waveguide/baffles size
to extend lower response for lower crossover point
otherwise once you see a half space response of
a specific tweeter, then observe diffraction on different
baffles.
modern free software can answer most your questions.
possible large back chamber. To achieve a driver
with low resonant frequency.
Which can be crossed low. Just reminds me of
the Swan designs around 2000 where they just
top mounted a large chamber tweeter.
Apply mystical magical sales speech to further
induce excitement.
You can get a TN28 driver for 20 bucks these days
Likely if you just became acquainted with common
diffraction modeling. Most of the mysterious and getting
a better understanding of why tweeters are mounted in
numerous locations. Will become more visually
easier to grasp
Make more sense when trying to match
specific drivers at a specific crossover point.
many work with 2k 3k or 4k points in a very generalized
manner with common textile domes.
But once pushing to 1k or lower your dealing with
a specific tweeter and likely larger back chambers.
Or larger baffles or waveguides.
Basically in all simplicity a lower resonate frequency
or combination of waveguide/baffles size
to extend lower response for lower crossover point
otherwise once you see a half space response of
a specific tweeter, then observe diffraction on different
baffles.
modern free software can answer most your questions.
Just circling back on this after I took a look at it-
Typical hard dome tweeter on baffle with large facets:
SB26ADC on 8.5" (21cm) wide cabinet, mounted near top, with facets:
B&W 802 D2 tweeter:
After @PKAudio 's crossover modifications:
ANSWER: Directivity control- Smoother and wider beamwidth.
Listening- spacious, open treble
Typical hard dome tweeter on baffle with large facets:
SB26ADC on 8.5" (21cm) wide cabinet, mounted near top, with facets:
B&W 802 D2 tweeter:
Reference:
https://pkaudio.webnode.cz/bw802d2/
https://pkaudio.webnode.cz/bw802d2/
After @PKAudio 's crossover modifications:
ANSWER: Directivity control- Smoother and wider beamwidth.
Listening- spacious, open treble
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And it looks like Focal has been understanding the benefits of slot diffraction where fwd lobing can be scattered a bit to improve too forward of a presentation. Acoustic lensing will be the next big thing in audio with todays tech…mark my words.
Possibly, although I suspect the slots are just a result of their 'Focus time' [no less] (known to the rest of the world and its walrus as 'time alignment' 😉 ).
Trademarked marketing-speak aside, I have to admit, an earlier version of the above speaker that I heard some years ago was excellent though.
Trademarked marketing-speak aside, I have to admit, an earlier version of the above speaker that I heard some years ago was excellent though.
That would presume phase response is audible. It also appears to overlook that diffraction and wide directivity is audible.
You could also put all the crossover components in the tweeter box. Otherwise it is just unused space....
Aha, easy enough to confirm/falsify: DSP mess up phase and time and EQ flat; measure IR; listen (mono and stereo) on-axis. Surely any true diyer (tinkerer) with DSP has tested this to their satisfaction?
Top-mounted tweeter can have any baffle or none; of course there's the step transition mid-to-tweeter.
(addendum)
1-way: test a small fullrange high-passed as mid-tweeter (such as SB65, SS 10F).
2-way: mess up phase response and digitally EQ flat.
Use instrumental voices with rich, high harmonics to test.
1-way: test a small fullrange high-passed as mid-tweeter (such as SB65, SS 10F).
2-way: mess up phase response and digitally EQ flat.
Use instrumental voices with rich, high harmonics to test.
Square waves can show us about phase. I posted a video here - https://www.diyaudio.com/community/...t-phase-coherent-speakers.420385/post-7855428
Sure. I didn't mention it because B&W didn't do it:
https://www.stereophile.com/content/bowers-wilkins-802-d3-diamond-loudspeaker-measurements
But yes, you or I could it (by physical adjustment of the tweeter position), or a different crossover (passive or active)
Whatever the designers at B&W goal was of separating tweeter from the mid, I cannot be certain.
I'm only presenting the facts from the fiction of (one of the) consequences of separating the tweeter from the enclosure.