synthesis1624705793 Posted August 23, 2007 Posted August 23, 2007 Just to share a bit... who knows can turn a few to DIYer.. Recently sold my JMLab Cobalt CC800S to make way for this center speaker to complement my DIY front speaker. The JMLab center is a fine speaker but I roughly know what to improve if I use the same Scanspeak midbass driver (18W/8531 G00) as my front. Seamless integration is one thing, but this midbass driver is capable of going down very low for the size such that it can match the bass of many floorstanders from bookshelf speaker enclosure. Deep articulate bass. Midrange is good too. Now the tweeter. Ideally I should match my front by using Scanspeak 9700 but I always wanted to try Vifa/Peerless XT TG25 30-04. This tweeter is quite interesting. It has smooth freq response, flat impedance curve and low resonance freq. On paper it's quite good, and inexpensive, too. ;) Well, you can find custom version of this tweeter in higher range of Sonus faber. So I went ahead with this tweeter. I don't want to build another curved speaker like my front, at least not this time. It's simply too much effort. But I don't want to build plain box either. I decided to build speaker enclosure with slanted front. This design created its own problem. Not only that I have to cut the side panels slanted, I also have to cut the top/bottom/front panels slanted in thickness direction and measure correct dimension accordingly. Using power jigsaw and temporary guide did help to cut more or less the way I wanted. The crossover design follows my front speaker, which is first order for midbass and second order for the tweeter. I need to adjust the tweeter crossover accordingly because the impedance rating is different. Here's the final outcome. The bass is good as expected. I still need to work on the tweeter crossover. It seems that I attenuated the tweeter a dB or two too much. The tweeter is smooth I don't think you can get fatigue from it. Initial impression is that it's not as transparent as the Scanspeak 9700 tweeter. But then it's three times more expensive.. :P All in all I'm quite satisfied with the outcome, though it's only a day old and still need time to run in. I think after tweaking the tweeter crossover, the sound should be better. :)
SiriuslyCold Posted August 23, 2007 Posted August 23, 2007 congrats :) looks like another well done speaker!
Darthfunk Posted August 23, 2007 Posted August 23, 2007 Well done bro! Congrats on your second project.
kzone Posted August 23, 2007 Posted August 23, 2007 should be the third at least..... the slanted design also solves the problem of having the door wedge to adjust its firing angle.. great job!!! now... how good it does it sounds? :)
synthesis1624705793 Posted August 23, 2007 Author Posted August 23, 2007 Thanks guys. It's my fourth. One is for my bro in law. Fifth if you include the speaker cum stand for my daughter's keyboard. ;) And yes that's the purpose of slanted front. :) The mid-bass is expected to be as good as my front. Now running in the speaker by replacing my front left with it and playing CD. Seems the tweeter is starting to wake up and my crossover design maybe correct afterall. Still I don't expect to be as transparent as Scanspeak 9700 tweeter, but not bad. The top end is smooth. :)
hifiluv Posted August 23, 2007 Posted August 23, 2007 wow...a beauty there...no more need for Ikea doorstoppers.....lol......
Smooth1624705821 Posted August 24, 2007 Posted August 24, 2007 Well done!! ;D I recognise the brown speaker wires. ;)
Darthfunk Posted August 24, 2007 Posted August 24, 2007 Btw for cosmetics do you intend to include piano finishing etc in the future or to stick with the current wood finishing?
SiriuslyCold Posted August 24, 2007 Posted August 24, 2007 Any reason you did not go with MTM config like the usual center speaker setup?
2100 Posted August 24, 2007 Posted August 24, 2007 You really ought to check out some of the pro-audio woofer drivers. But at least yours is also paper.... I am a paper convert! ;D
synthesis1624705793 Posted August 24, 2007 Author Posted August 24, 2007 Btw for cosmetics do you intend to include piano finishing etc in the future or to stick with the current wood finishing? No piano finish. Any slight imperfection will be revealed. your veneering....SOLID!! ;) Err... you better don't inspect it so close. There are a couple of corners that are overcut. ;) Any reason you did not go with MTM config like the usual center speaker setup? This midbass driver cost me $352+GST. You want me go broke? ;D Whatever the benefit of MTM configuration, theorethically or practically, this one is good enough. ;) You really ought to check out some of the pro-audio woofer drivers. But at least yours is also paper.... I am a paper convert! ;D Hmm.. never thought of that. I'm really satisfied with this midbass performance. No complain so far. :)
2100 Posted August 24, 2007 Posted August 24, 2007 Hmm.. never thought of that. I'm really satisfied with this midbass performance. No complain so far. :) They are very very good. Check out da bass from the Proac D100 (modded Volt 2500s), shd be your fav brand also ah? :) Actually the midrange also pro-audio (ATC SM75). BTW it is pro-audio or studio, not PA as in Public Address. ;D
2100 Posted August 27, 2007 Posted August 27, 2007 I think can find a lot of help here to make it better. http://www.zaphaudio.com/ZD5.html
synthesis1624705793 Posted August 27, 2007 Author Posted August 27, 2007 Thanks. Somehow I want to do it my way. I would have copied from this following site if I wanted to copy. ;) http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
2100 Posted August 27, 2007 Posted August 27, 2007 Thanks. Somehow I want to do it my way. I would have copied from this following site if I wanted to copy. ;) http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm Yes, the xover looks good. Somehow I still feel a lot of drivers need notching instead of say a straight 2nd, 4th order and invert polarity etc. Real life not that convenient. Even the SF Stradivarius wide baffle is there for the reason of BSC. "Poor" guys like us without any proper tools are very helpless with only our ears. Another popular one with good comments overall would be the Faktum. But this one must use a very good SS. http://www.lautsprechershop.de/hifi/faktum_en.htm (wait for the pages to stop auto-refreshing). Let me quote : "It takes five minutes to order a box of drivers and you can spend months and months on learning the strengths and weaknesses of each driver, trying to find the optimum points of crossover and the optimum crossover slopes for producing the best blends of sound that hopefully will integrate the drivers into a coherent and pleasant presentation. The number of options seems infinite."
synthesis1624705793 Posted August 27, 2007 Author Posted August 27, 2007 After I built my DIY Response 2.5, I tought I wanted to copy SP95 from Troel's website. The measurement looks good but it may not necessary suit our taste also. So then I decided to design my own for my bookshelf speaker so I can learn more in the process. It's always been a WIP for quite sometimes but it's quite an interesting experience. With some educational guesses, at least we can have a good start and understand where to improve to suit our ears. ;) Btw, I believe it's easier to design a crossover with good drivers ;)
Spunky Posted August 27, 2007 Posted August 27, 2007 Some said the XT25 is not easy to crossover. What does your highpass look like?
synthesis1624705793 Posted August 27, 2007 Author Posted August 27, 2007 Some said the XT25 is not easy to crossover. What does your highpass look like? If you look at the crossover photo, it's 2nd order at about 2kHz (Linkwitz Riley formula) and 4dB attenuator to match the midbass. XT25 has flat freq response and flat impedance curve, I don't know why it's difficult to crossover. Maybe I miss something. Probably it's rather not easy to the amp since it's 4 ohm. Anyway if anybody's curious how it perform, audition is welcomed. :)
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