Stick with the 28 in if you can - best to see what original design can do. I am going to be on travel over next 3 days so will not be able to check posts as often
Good luck!
Wise words - debate all we like about the exact classification of this interesting design of Steve's (or any of the wide range of "hybrid / BLHs" extant) - one thing's that's probably not much in doubt is that members of this genus can't just be "scaled up to fit the larger driver I'd like to try, or my aesthetics, etc." and expect to perform as well as, much less "better than" the original.
Yes, you could re-engineer from the ground up, in which case you might not arrive at the same topology - flare rate, CSA, path length, terminus location, number of folds etc.
I think the DNA-design is asking to much in bass response.
There is always a price to pay for extended bass response. Sensitivity, Group delay, peaky performance, very high demand on the drivers Xmax-performance.
This is not, (in my opinion), a balanced approach for full range drivers.
Why not use that cabinet volume and settle for a reasonable 40-45 hz extension and keep overall sensitivity up with the mids a highs?
That would make more sense, me thinks.
/Jacozz
There is always a price to pay for extended bass response. Sensitivity, Group delay, peaky performance, very high demand on the drivers Xmax-performance.
This is not, (in my opinion), a balanced approach for full range drivers.
Why not use that cabinet volume and settle for a reasonable 40-45 hz extension and keep overall sensitivity up with the mids a highs?
That would make more sense, me thinks.
/Jacozz
One 95% DONE !
This stuff is really different. Once the membrane is removed the hot glue can melt the foam. Luckily my gun had a low setting. I tried to wipe all the joints but some blade work will be needed. Might cover all the internal bends with something like 6L6 did on the Cornu.
Drivers will be here tomorrow so there may be an audition by this time in the evening. (I know Cal, DIYers should never say "I'll be done in about......")
DNA next to Sunflowers.
This stuff is really different. Once the membrane is removed the hot glue can melt the foam. Luckily my gun had a low setting. I tried to wipe all the joints but some blade work will be needed. Might cover all the internal bends with something like 6L6 did on the Cornu.
Drivers will be here tomorrow so there may be an audition by this time in the evening. (I know Cal, DIYers should never say "I'll be done in about......"
)DNA next to Sunflowers.
Attachments
Landed in LAX, will be here for next couple of days. Very nice progress there Bob! Looks great. Will you be cutting a round hole or a slot for the throat? I assume it is easy to cut the stuff in-situ with an x-acto or something. I am glad the drivers will be there tomorrow - can't wait to hear what you hear.
I think you have good points here, but I think what Decware wanted was kind of a speaker that elicits "wow that horn really puts out some bass, are you sure you don't have a subwoofer connected?" type response from a casual passerby. At 40 Hz and below, I don't think group delay matters much to me. The sensitivity isn't bad by any means as there is enough bass to negate the need for BSC. The speaker was targeted at low watt amplifiers (6 watts max) and this makes sense because at 4 watts and 30 Hz, the driver basically is hitting its xmax.
The neat thing with this speaker and what Bob is doing is that he can build it in day or two, it costs almost nothing, the driver costs almost nothing. So you really have nothing to lose but your time. The potential payoff is a really neat piece of technology. I don't know of any other 5 inch class driver speaker that puts out that much bass at 30 Hz. I should try to see if I can plot the group delay with the AkAbak sim. It may not be that bad. Horns tend to have less group delay than a straight BR, correct?
I can definitely say that this design is very sensitive to the driver choice as I was able to test that out with the simulation. Note that the simulation was based on manual dial caliper measurements of throat/mouth and line length dimensions of the incorrect stretched out aspect ratio drawing. I imagine this might add a few extra Hz of bass extension due to the longer length of the horn path and increased volume of the chamber. But what is interesting is that the design still works (according to the model) even though it was stretched 20% in the vertical dimension.
I'll take your recommendation whether to use a slot or a hole. This stuff cuts easily and cleanly as long as the blade angle is low. I have a set of hole cutters if I go that way.
One concern - there may be another short pinch that needs to be adjusted. I'm not that savvy about the dynamics at a turn like that. I've already removed the two blue pieces but need advice on how critical that small segment is.
Other horn gurus can answer if X is still busy preparing for his appearance on the Tonight Show.
One concern - there may be another short pinch that needs to be adjusted. I'm not that savvy about the dynamics at a turn like that. I've already removed the two blue pieces but need advice on how critical that small segment is.
Other horn gurus can answer if X is still busy preparing for his appearance on the Tonight Show.
Attachments
I'll take your recommendation whether to use a slot or a hole. This stuff cuts easily and cleanly as long as the blade angle is low. I have a set of hole cutters if I go that way.
One concern - there may be another short pinch that needs to be adjusted. I'm not that savvy about the dynamics at a turn like that. I've already removed the two blue pieces but need advice on how critical that small segment is.
Other horn gurus can answer if X is still busy preparing for his appearance on the Tonight Show.
Bob,
I saw this pinch too. Not critical - it hardly changes the response in the model if you adjust it one way or another within a few mm. If you want a truly expanding horn, rotate the lip CCW a few degrees until the flow passages are expanding on both sides.
Yes, I will be talking about Foam Core speakers on the Tonight Show. Jay L (or whoever the host is? - guess you can tell I don't watch those shows..) is a big DIYAudio fan
Fantastic !! I hope he took some photos during the build. This is my first horn other than the Cornu but I can see it's a style that can be very enjoyable for woodworkers. I'm going to make a 1/4" thick ring glued on the inside for driver mounting.
@struggles - are you incorporating a tweeter?
@struggles - are you incorporating a tweeter?
Bob,
This looks very much like a fun time. Too bad all I can do is run sim's of the model
I was thinking that this speaker may be the perfect match for the Pass ACA at 5 watts? Not sure if @struggles took photos - I hope he did too. I am real curious how the tweeter you mentioned earlier will make a difference to. Probably essential with this driver as it pretty much starts cutting out after 10kHz. Were you going to put a thin 1/4 in plywood veneer on the baffle to make it look better and also to provide purchase for the screws?
This looks very much like a fun time. Too bad all I can do is run sim's of the model
I was thinking that this speaker may be the perfect match for the Pass ACA at 5 watts? Not sure if @struggles took photos - I hope he did too. I am real curious how the tweeter you mentioned earlier will make a difference to. Probably essential with this driver as it pretty much starts cutting out after 10kHz. Were you going to put a thin 1/4 in plywood veneer on the baffle to make it look better and also to provide purchase for the screws?