diy studio monitors

[brsanko]

Wow this is too much to comprehend this late at night. I though I knew a little bit about electronics and speaker design but your crossover designs are beyond me. At least tonight. I'll have another crack at it tomorrow. But I'm bound and determined to build the best studio monitors I can so keep the info comming if you don't mind teaching me a thing or two.

[Jay_WJ]

Originally posted by brsanko
but your crossover designs are beyond me.

If you mean my Usher 2-way design, yes, it does look complicated at first. But it simply () consists of an electrical third order low pass filter plus a CLR notch filter in the woofer network and an electrical second order high pass filter plus a CLR notch filter in the tweeter network.

Perhaps, you haven't seen how complicated some of very respected speaker designer's crossover work is. For example, look at:

http://www.htguide.com/forum/showthread.php4?t=11321
http://www.htguide.com/forum/showthread.php4?t=13154
http://www.zaphaudio.com/ZD5.html

Compared to these, mine should be much easier to understand.

[brsanko]

Yeah wow that's some intense stuff. I'm reading Zeph's site it's some good stuff. I think I might just make one of his designs, not sure yet. I've been reading up on speaker and amplifier design for about 7 ort 8 years now and I still have so much to learn I didn't have internet for a while so I've been out of it for a while, but it is facinating. I've found that people who are really passionate about one design or another are typically ignorant of the advantages of other designs and the short falls of their own. I have the distict disadvatage of not having that much money so must of what I know is from reading not from listening. but hopefully soon that will all change.

[brsanko]

Ok I spent several hours looking at Zaph's site and his reviews and tests of drivers and have come up with another design all my own. I'll start with a PE premade curved .25 cu ft cab and, leave it sealed. The woofer I liked for my purposes was the Seas P18RNXP, and for tweeters I like the North D2506-S a crossover point somewhere between 2500Hz and 3000Hz using either a first order crossover, or an electronic active crossover and a five channel amp, with the subwoofer I described above. Now please feel free to tear this design apart. I've learned alot in the last couple days

[Jay_WJ]

First, the PE 2.5 cu ft cabinet's baffle is only 7.5" wide and its usable width excluding the edge roundover is only 6.5". So you cannot use it for a 7" driver.

Second, the Seas P18RNX is not the best Seas Prestige 7" w.r.t. distortion performance. It is the new ER18RNX with its improved motor design.

Third, the North tweeter has been discontinued. No longer available

Fourth, if you want to have the same setup as mine (small sealed or vented standmounters plus a subwoofer), look no further than the four designs at my web pages. You're not going to find better driver combinations for 2-ways within a reasonable budget. I know this because I've already done a lot of homework. For possible 7" driver options I've found, see this post: http://www.diyaudio.com/forums/showt...68#post1320168
If you read Zaph and Mark K's driver test pages over and over again, you'll agree with my choices.

BTW, when you look at frequency response plot in Zaph's 6.5" driver test page, ignore response below 500 Hz. He used a very short gating for measuring the FR of this group of drivers.

[brsanko]

well according to this page you can still get the tweeter http://www.northcreekmusic.com/WhatsNew.htm I guess I'll have to have my cabinets custom made. Is the woofer you mentioned on Zaph's site? I'm sure your designs are incredible and outperform anything I'll come up with but comming up with the design myself is half the fun. Heck it's about 80% of the fun. I've still got a lot to learn about crossovers and I think I'd like to understand a design completely before I build it so my goal right now was to find drivers that would lend themselves well to a simple first order design. I'm not quite sure yet if I've done that. I still want to take a closer look at the 5.25" drivers and see what they have to offer. Thanks for all the advice.

[Jay_WJ]

You need to know that the electrical first order (acoustic LR2, to be more precise) is really not simple to design. To obtain good phase tracking, you'll need 1) slanted or stepped baffle, 2) delay network, or 3) waveguided tweeter. Also, there are not many choices of low-distortion drivers that satisfy the requirement of LR2 design: flat response at least 2 octaves above and below the XO frequency. This is why the acoustic LR4 design is more popular; easier to implement.

To understand this better, read Zaph's ZD5 and Waveguide TMM design pages.

Also, if you want to have fun, how about using one of the driver combinations of my designs and designing your own crossover?

There are not many 5.5" drivers that outperform the 6.5" drivers in their distortion performance even in midrange---I honestly don't know why, but that's the fact. You'll know if you research more.

All the drivers I mentioned are in Zaph's page. Also, don't forget to look at Mark K's test pages. His test method is very thorough.

[Jay_WJ]

Before I forget, some more things to consider.

When you look at harmonic distortion measurements, remember that 3rd and 5th order harmonics are much more important than the 2nd order one. They are more audible and have worse effects.

When you read tweeters' distortion measurements, distortions above 4 to 5 kHz are not so much meaningful. For example, a high 5th order harmonic at 4 kHz is not important since it is at 20 kHz---not audible. You need to focus on their distortion levels between 1.5 kHz and 3 kHz.

[tinitus]

If you insist on doing your own with 6db filter i would go for a 3way
Could be a Hivi M12 12" woofer and a Tangband W3-1285SG, supertweeter Vifa XT19 ... xo points about 500/5khz
but there are lots of options

[brsanko]

Ah I see that explains why the distortion graphs only go up to 10khz. I had assumed the graph showed the distortion at the frequncy where it was heard not at the frequency that produced it, critical bit of information. It's going to take me a while to understand all the complexities of crossovers but that is ok because it's going to be a few months at least before I have the money to impliment the designs in the first place (expecting a large settlement soon). Maybe I should forget about comming up with design ideas and concentrate on learning for a while. Of course this isn't quite as much fun. Now I've heard it's i'ts important to keep crossover frequencies out of the critical midrange but I guess I'm not sure what frequencies ore considered critical. Thanks again for all your help