soongsc said:
The birch ply (with MDF back) ones have the same problem so it's not the bamboo. The inherent nature of the design doesn't leave a lot of room for the box to move around.
dave
Scottmoose said:
unskinned plenum grade Cat 5 -- solids together & stripes together. Those pics are at Chris' place (his front end is better than mine so we do serious compares there -- since he does the build also the 1st place they usually get fired up)
dave
soongsc said:
for instance, female vocals sound like the singer is at he bottom of a well.... cupped, closed in.
dave
planet10 said:
Does it measure good but sound like that or just listening first? I guess you don't have BSC of any sort in there, right?
Measure?
With all due respect - after over 35 years of listening, I don't need to measure when it sounds this coloured.
Regarding BSC, I'm not a fan of passive frequency EQ filters; in fact one of the huge benefits of bipole design is the elimination of the need for it, even with relatively small drivers and narrow baffles.
One of the FR125's strengths is the combination of low frequency extension, excursion and very low distortion, albeit at the price of sensitivity. That, in combination with a very large front baffle and boundary reinforcement from the side exit "horn" of the PAWO provide more than adequate energy at the low end for this listener.
Having built quite a few speaker enclosures over the years from a variety of materials, I'm confident the bamboo is not part of the problem. 19mm (3/4") block core laminated bamboo plywood is pretty damned stiff, and the numerous internal panels of the PAWO provide for a very well braced box.
In fact the esthetics of the results is probably the main reason I haven't moved on entirely to another project. My wife couldn't care less the sound, but is always eager to comment on the look of any new visitor to the livingroom she's letting me "borrow". This is a cute little design, and with 5 coats of nitrocellulose lacquer, they are quite pretty - it'd be more than just a shame to burn them.
Sorry Tom, but after several listening sessions to both the BB plywood and bamboo pair, I'd agree with GM's comments on FR forum regarding the compression chamber. I plan to revisit that during the next week or so, and report my observations.
Regarding the bipoles, we always have way too many designs percolating in our minds than we'll ever have time to get done; it was serendipity that these were the next pair built. As Dave has already provided the Cole's Notes summary of advantages of BP design, I won't repeat; other than to state that properly executed, it can to a very great degree help make the box disappear. This is by far the best combination of performance and WAF of our 5 FR/WR125 designs to date.
While the best speaker enclosure I've ever heard is no enclosure ( open baffle), and I've even built a few of those as well ( but just can't keep them in the house), the designs that are most emotionally satisfying have been bipoles. The soundstage, imaging , depth, and articulate bass, ( even when limited in extension by the driver's parameters ) have become a personal benchmark. In it's current state of development the FR125 in the PAWO is "sorry Charlie....no cigar", but not with out potential - there are many brilliant and just plain stubborn DIY'ers out there
With all due respect - after over 35 years of listening, I don't need to measure when it sounds this coloured.
Regarding BSC, I'm not a fan of passive frequency EQ filters; in fact one of the huge benefits of bipole design is the elimination of the need for it, even with relatively small drivers and narrow baffles.
One of the FR125's strengths is the combination of low frequency extension, excursion and very low distortion, albeit at the price of sensitivity. That, in combination with a very large front baffle and boundary reinforcement from the side exit "horn" of the PAWO provide more than adequate energy at the low end for this listener.
Having built quite a few speaker enclosures over the years from a variety of materials, I'm confident the bamboo is not part of the problem. 19mm (3/4") block core laminated bamboo plywood is pretty damned stiff, and the numerous internal panels of the PAWO provide for a very well braced box.
In fact the esthetics of the results is probably the main reason I haven't moved on entirely to another project. My wife couldn't care less the sound, but is always eager to comment on the look of any new visitor to the livingroom she's letting me "borrow". This is a cute little design, and with 5 coats of nitrocellulose lacquer, they are quite pretty - it'd be more than just a shame to burn them.
Sorry Tom, but after several listening sessions to both the BB plywood and bamboo pair, I'd agree with GM's comments on FR forum regarding the compression chamber. I plan to revisit that during the next week or so, and report my observations.
Regarding the bipoles, we always have way too many designs percolating in our minds than we'll ever have time to get done; it was serendipity that these were the next pair built. As Dave has already provided the Cole's Notes summary of advantages of BP design, I won't repeat; other than to state that properly executed, it can to a very great degree help make the box disappear. This is by far the best combination of performance and WAF of our 5 FR/WR125 designs to date.
While the best speaker enclosure I've ever heard is no enclosure ( open baffle), and I've even built a few of those as well ( but just can't keep them in the house), the designs that are most emotionally satisfying have been bipoles. The soundstage, imaging , depth, and articulate bass, ( even when limited in extension by the driver's parameters ) have become a personal benchmark. In it's current state of development the FR125 in the PAWO is "sorry Charlie....no cigar", but not with out potential - there are many brilliant and just plain stubborn DIY'ers out there
I am running my Fr125 on open baffle. Like it very much. It sounds very open, relax, effortless.... The interesting thing is that it sounds louder around the house than at the listening position...
I think it's good to gather as much data as you can before coming to a conclusion. Just good engineering practice ans risk reducing efforts.
Bipolar should (I'm just getting interested in bipoles afte hearing a few) provide identical benefits to dipolar with the figure 8 radiation pattern, correct? Out of interest, what sort of differences should one expect from bi and dipole speakers (assuming identical drivers used)? I assume the bipoles would probably reach lower, especially if an MLTL or reflex design is used?
Best
Scott
Best
Scott
Scottmoose said:
No, not at all. Bipoles radiate as much (or more?) energy to the sides than a monopole. Dipoles have the figure 8 radiation pattern because the front and back waves are out of phase and they cancel each other at the sides of the speakers.
Aha. That clears that up; thanks for that. i really should have been able to work that one out if I'd bothered to think about it. I must be getting old.
My own dipolar setup I sold recently, as it needed far too much room (which I don't have) -I will give bipolar types a whirl in the near future though...
My own dipolar setup I sold recently, as it needed far too much room (which I don't have) -I will give bipolar types a whirl in the near future though...
To expand on that last... at higher frequencies a bipole will have a figure 8, but unlike a dipole the front & back are in phase... as the frequency deceases the response becomes more & more omnipolar.
dave
dave
planet10 said:
If you can get the directional driver to fire up, and reflect them in an omni direction, then you can get omni throughout the audio range. The design is a little tricky though.
soongsc said:
For our purposes omni radiation is a side-effect of bipolar and not the reason for doing it.
dave
I'm glad that the Bipolar Bipolar design has proven to sound most satisfactory. These FR125S drivers really are so very good and deserve extensive cabinet experimentation! I'm sorry that my Pawo design did not live up to expectations, esp. since they are so lovely with the Bamboo wood.
With the female voice sounding distant, I rather doubt it is the shallow depth of the cabinet causing this since many backhorn designs have an even shallower depth behind the driver and often suffer from a too forward presence in upper midrange. But perhaps, the less stiff nature (compared to BLH designed drivers) of the FR125S makes such close proximity a problem?
During the next week I should hope to experiment with the drivers further. Plans are open baffle and sealed box with the driver mounted on the 12 inch wide panel. I just can't bring myself to go away from the wide panel with its virtues of a large image, and the freedom from early wall reflections with the resulting increased pitch definition (more like big headphones ..."roomphones").
Also with the intended experimental cabinet continuing to be short in depth, I also wonder if a secondary/rear driver can be placed up/down in relation to the front firing, or do the drivers really need to be back to back for an even piston motion?
~Tom
With the female voice sounding distant, I rather doubt it is the shallow depth of the cabinet causing this since many backhorn designs have an even shallower depth behind the driver and often suffer from a too forward presence in upper midrange. But perhaps, the less stiff nature (compared to BLH designed drivers) of the FR125S makes such close proximity a problem?
During the next week I should hope to experiment with the drivers further. Plans are open baffle and sealed box with the driver mounted on the 12 inch wide panel. I just can't bring myself to go away from the wide panel with its virtues of a large image, and the freedom from early wall reflections with the resulting increased pitch definition (more like big headphones ..."roomphones").
Also with the intended experimental cabinet continuing to be short in depth, I also wonder if a secondary/rear driver can be placed up/down in relation to the front firing, or do the drivers really need to be back to back for an even piston motion?
~Tom
TomekZ said:
We haven't given up... we are going to see what happens when we enlarge the compression chamber 20%.
dave
TomekZ said:
To get maximum active vibration cancelation from the push-push, they do need to be magnet-to-magnet.
dave
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