Half Chang build

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Thanks Scottmoose. I will take your word for it because I follow what everyone else is doing, you have great knowlege about this subject.
I was thinking of using a different material for the front baffle. 1/4" T6061 aluminum with some dampening material to control reflection on the inside and outside if needed. Cleat mount the front baffle for easy mods. I think the aluminum is much stiffer then ply. Back mount the speaker and cut a 1/4"bevel for the speaker. What do you think?
Peter C.
 
Thanks Scottmoose. I will take your word for it because I follow what everyone else is doing, you have great knowlege about this subject.
I was thinking of using a different material for the front baffle. 1/4" T6061 aluminum with some dampening material to control reflection on the inside and outside if needed. Cleat mount the front baffle for easy mods. I think the aluminum is much stiffer then ply. Back mount the speaker and cut a 1/4"bevel for the speaker. What do you think?
Peter C.


while not Scott, I'd opine that the aluminum would work very well as proposed and is thin enough that beveling would not be necessary
 
I don't have any materials density charts etc. to hand with MOE values (what I had was on an old Zip disc, long since dead, along with the drive), but something like 12ga CRS would make a fantastic box, & I see no reason why aluminium should not do the same. Rings like a bell, but so far out of the box's functional BW it will be very easy to damp. Go for it. :)
 
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Hello chrisb: The 6061 1/4" is nice stuff to work with. It can be cut with a circular saw with a carbide blade. The beveling is to make it look good.
Scottmoose: Thank you for the "Go for it"
-Rings like a bell, but so far out of the box's functional BW - Sorry, but I don't know what functional BW means.
I plan to use the brace and screw the aluminium to it with 1/32" black rubber between the brace and the baffle to act as a bit of a anti ringing system. I am still planning as I have other things to do, but the planning stage of this Chang is lots of fun. See what everyone is doing and using ideas to combine them into something what I will be proud to build.
Peter C.
 
A 10" X 34" X 1/4" plate is 85 Canuk Bucks. The ply is, depends from where I buy it from, $80 to $120 4' X 8' X3/4" sheet in Toronto.

First I will make the cabs. without the baffle then take precise measurements of the opening to fit the baffle. I presion cut the plate to fit. In case of offsets. With cleat mounts I can change the baffle to other materials as suited.
Nice to see input!
Peter C.
 
This is message for Scott. I will be building the Half Chang's soon and planned to implement the BSC recommended by Martin King his MLTL 207E virtual project. The circuit is here:

FE207E Baffle Step with 6 ohm resistance

Is baffle step necessary for this design? The speakers will be SS driven.

Thanks for all the help and a great design.

Bill

I would also like the plans for this but everytime i try the link i get handbag websites, i think it has been hijacked, could we try again please or just post a link without linking if you see what i mean? regards, Nick
 
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[rant]

The whole reason for the big double BVR's like Chang is to get a "big" sound that is generally lacking in single driver speakers. It's not bass that is lacking, but the grunt frequencies -- 60-100Hz -- where the 6-8"ers run out of excursion. Why one would expect to get useful results out of a 3-5" driver is beyond me. No Sd means no air movement.

I'm still trying to find a cabinet for FE127E's. Yep, I get bass to 60Hz -- at 60 dB @ 1m, but I can't get 80dB average at 2m without horrendous distortion. And I'm talking baroque music where the biggest instrument is a theorbo. Sure, huge horns would probably work, as might corner horns, but I don't have usable corners.

I remain steadfast in my opinion that drivers smaller than 6" are midrange drivers and need to be rolled off below 200-300Hz.

[/rant]

Bob

Respectfully disagree, a tube amplifier with the small Karlson with FE-166En (that I built many years back) gave chest thumping bass. The cone hardly moves. Kids now have them with a solid state amplifier and could not be happier (combined with enabled FE-127E for mid-high). At the moment I am listing to the FE-167E with an Audio Note push pull clone and am more than happy.

AM
 
Probably not; note that the former was not designed for the FE206E[n] -those were merely option drivers that requires some series R or an amplifier with a high / adjustable output impedance for proper function. Beyond that, since the alignments and design goals are fundamentally different, comparisons in essence simply illustrate that, i.e. they're different. Technically Dallas II is a superior design for the 206, at the price of greater size and complexity.
 
Hi Scottmoose,

thanks for swift response. I'm entirely aware, that Half Chang was initially designed for FE207, however after reading all this thread I expect to get good results with FE206en, obligatory with BSC circuit.
The amplifier I have is tube EL84 based and has 4 and 8Ohm outputs.
The reason why I'm looking at the Half Changs is that they are more slender that other projects, which are in majority too huge for my room.
Are you able theoretically compare Half Chang and Dallas II in terms of sound quality and attributes?
 
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FE207E rather than the FE207 (a slightly earlier driver).

A baffle step compensation (low pass shelving) circuit is not obligatory: as noted though, some series R or a high / adjustable output impedance amplifier is, for the alignment to work roughly as designed. Baffle step isn't a major issue with this enclosure if it's near room boundaries, although the same circuit topology can be used to flatten the naturally rising HF response of the 206E[n] (separate issue).

Unfortunately not, since sound quality is subjective until it's defined technically. So it depends how you define it in terms of, say, frequency response, distortion, acoustic efficiency &c. Dallas II is the more efficient load & operates over a significantly wider BW, with all that entails.
 
Hi,

thank you for clarification.
As to the sound quality/attributes, I had in my mind i.e. FR linearity, audible stage effect depth and width.

I'm aware that your impression might be just theoretical. I just want to know whether Half Chang is able to present full performance of FE206en.
Alternatively maybe you could suggest some other well performing enclosure for this speaker, similar to the HC in terms of dimensions.
 
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I have half changs with fe206ens and my wife and I are both wowed by the sound. No sub needed at all. A quick search will yield similar experiences. I'd like to try them in dallas IIs but life keeps getting in the way. It's always something. Are your drivers broken in? If not, expect not to like it for the first 100 hrs or so.
 
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