SB 12.3 010.jpgSB 12.3 001.jpgSB 12.3 002.jpgSB 12.3 003.jpgI have more photos here.
Note that it is hard to round off the edge of the baffles if you do not have the tools so I used a semi cylindrical flushing which you can purchase from any hardware store and glue to the side. Not shown on photos.
With the cross over outside the cabinet I can tweak it as often as I like.
Try substituting R0 for 1.35 ohms and R9 for 1.5 ohms. So far I find this option to be the best sounding and very detail.
Really looks great! I hope you are enjoying them throughly!
They looks nice, kennethloy. And big!
Good idea about cylindrical flushing. I was going to use router once i'm ready to re-veneer cabinets later (I used pre-veneered MDF for a quick start) but for now it will do. Those sharp edges really affect sound by that much?
Do you feel like stock cabinets are strong enough? I worried 25/19mm mdf is not all that much so i tried reinforcing joints and adding bracing to upper part of back wall http://img72.imageshack.us/img72/293/05102011688.jpg
Do you run separate wire to each mid driver or one to both?
Sharp edges caused diffraction to sound waves in the high frequencies therefore definitely affects sound making it sound harsher.
Vibrations also affects sound quality therefore it is better to be sure with additional bracings as it would be difficult to redo the cabs once everything is installed. However, the additional bracings may reduced the volume of the cabs.
In contrast, whether, you run separate wires or not to mids will make no detectable difference to sound for the length of wire concerned. You need to consider how to seal the mid's cabinet and if too many wires runs into them it is harder to seal more holes. John said the mid's cabinet must be air tight for the impedence trap to work.
Figured it out on my own. And it's easy to test if cabinet is sealed airtight by pressing on one of the mids- the other one should come out and stay this way until you realease the first one. And it's definately easy to feel if there's a pressure fighting you once you press the woofer.
I gotta try aperiodic since the bass, although deep, doesn't produce the midbass "impact" i was hoping for. Also rounding enges may help to reduce slight emphasis somewhere between mid-highs, or i'll have to tweak filter.
Last edited by AlexanderTD; 03-23-2012 at 05:35 AM.
Reason: Got it figured out
Finished my test-build of sb12.3 The box (bass) is about 1 cu. foot larger and i use my own assembled crossover for now. All capcitors/resistors/inductors values was double checked, there's only a slight difference in DCR (mine are lower), but nothing that can really affect anything.
Didn't exactly do any real measurements yet, but did a quick check of frequency response using AV receiver with audissey and it shows exceptionaly flat graph.
Hovewer, practical tests confirmed that some treble frequencies are dominating. All the "tssss" and "shhhh" sounds are too loud and harsh and overall sound is kinda bright. I imidiately suspected difraction issues as my baffle edges are not rounded yet so i took 2 large sheets of felt, cut the holes for drivers and attached it to the front baffles to damp possible diffraction and see what happens.
The result confirmed it - overall balance imidiately got right, gone are those harsh "tssss/shhh" and i can listen to some rock music without my ears bleeding once solo guitar starts to play.
So in the end i realized i should pay more attention to how well i flush mount tweeter/mids on such a large baffle.
I'm going to fix it soon, but I also had idea of building completely different box with mid\tweeter in a separate narrow box and bass is in box of it's own (with same center distances etc), do i need to change anything in crossover?
Good evening to all members I'm new registered on forum and I have the same query concerning modification of enclosure in two parts, where tweeter and midwoofers can be located on a narrow enclosure which will be attached on a separated woofer enclosure
Originally Posted by AlexanderTD
Looks like we're on our own here
Originally Posted by tasos kyr
I thought it won't hurt anything and will only alter/reduce diffraction effect at first but now i'm not that sure as baffle has significant effect on drivers performance.
Also your bass enclosure is going to be very deep if you keep baffle width/height the same - need to figure out how to make it look good as well
Last edited by AlexanderTD; 05-04-2012 at 04:27 AM.
Reason: new thoughts
Rounded cabinet corners are much less likely to cause a frequency response aeration that affects sibilance on T's and S'es that would a poorly countersunk tweeter. (or worse, no countersink surface mounted) But that said, felt would indeed help both that and unrounded edges. Most people hate felt however because it is so ugly.
Originally Posted by AlexanderTD
Building a separate mid/high enclosure of a narrower width will affect the 2pi to 4 pi transition frequency, along with some of the diffraction ripple, and throw off the crossover a bit. I'd recommend playing with the Baffle Diffraction Simulator to see the difference and decide for yourself if that is acceptable. Remember that Audessy could fix wide band problems cause by a non-optimal enclosure. I'm not sure however if it would fix narrow band ripple response issues. That however could be solved by listening on a different axis. Once again, play with BDS to determine optimal off axis and position speakers accordingly.
Thank you for response! Maybe you can help to understand one more thing - when i cover entire baffle with felt, do i virtually "remove" baffle (since all diffraction is consumed by felt) like there's no baffle at all as well as baffle step? http://img402.imageshack.us/img402/6451/voylok.jpg Because it sure sounds/measures like it.
Originally Posted by jkrutke
Maybe i can "simulate" narrow baffle by making a hole of the right dimensions to see\measure how it works in a real world..