A good tweeter to match 5" SB Acoustics Magnesium Woofers

[xmax]

Interesting it seems the resistor is the only thing keeping both the chokes and caps "split"
Clearly the difference with your pad/transfer resistor is the higher frequency third order filter...
Distortion generator, that's funny.

[DDF]

I don't see your 2 choke low pass filter, what am I missing? I use the W6-1721 and it can also get a little nasty,
my monitors are sold as a system with the amp so I can cheat with a mild mid dip circuit, but since a lot of
clients like the more forward mid range there is a switch to by-pass it. As a smart person said earlier in this
thread I am too stupid to even know I am stupid so I don't know any better to know any better, none.

Look at "Part 1" pdf posted tonight, the crossover is published there. The coil is split into two, both coils implement traps, one only damped by the inductor's resistance and used to notch the nasties 8 to 12 kHz, the second damped with a parallel resistor to provide a low Q dip ~ 1 to 2 kHz and get rid of the excessive peaking there in the driver. Both coils still add up with the cap to ground to make a nice low pass.

Also check out at the huge resistor before the tweeter and still the massive roll off of the high pass (no distortion generator there, LoL!)

[xmax]

I don't see your 2 choke low pass filter, what am I missing? I use the W6-1721 and it can also get a little nasty,
my monitors are sold as a system with the amp so I can cheat with a mild mid dip circuit (in the amp), but since a lot of
clients like the more forward mid range there is a switch to by-pass it. As a smart person said earlier in this
thread I am too stupid to even know I am stupid so I don't know any better to know any better, none.

[DDF]

I didn't address this in my first response. While I agree that when it's possible to use a wide overlap that it can provide a smoother off-axis and power response. When you can select the drivers that allows for selecting a match that allow is. For my 2-way above I was given the drivers by zaph on the condition that I publish a design. I went farther and added the detail of my design process for it. You really can't do a low slope crossover primarily because that midwoofer has a rather nasty peak/breakup area that will be too high on-axis.
dlr

If the peak is relatively stable in frequency over angle, it's handy to notch it out by splitting the main low pass inductor in two and adding a small cap across one. Still allows broad overlap and well controlled off axis. I just updated the design spec for my Napoleons showing how this can be done over at diyaudio, and the off axis is crazy good all things considered with tons of tweeter power handling

http://www.diyaudio.com/forums/multi-way/234674-napoleons-compact-2-punches-weight-5.html#post5308848

Anyone working with the W4-1720 would probably find the measurements and crossover recommendations interesting. That's one high maintenance little woofer!

[Billet]

I have to admit wincing more than once at some of the verbage in this thread, but in the end lots of good discussion and ideas came out of it. I actually thought it was becoming more civilized in the past day or two. We do not all have to agree with each other, what is the good in that? We can all learn something from somebody.

[xmax]

I choose my wording poorly and I apologize again. People have crapped all over my post for at least 12 years
on this forum no big deal. The filter is the same as the Zaph ZMV5 minus the (2 ohm!) shunt and lower series
resistor, The tweeter has a very close Fs and Z with similar Z peak as Fs, clearly a coincidence
because the Zaph design is about half the impedance.

Still proving there are many very different ways of doing things.
I also find it interesting that the cap coil ratio is almost exactly text book Bessel which is
favored for it's Q and fast settling time, @ 4 ohm which Zaph only changed slightly for I'm guessing
the transfer function, I'm sure another coincidence.

I admit I came off like a mega jerk face and I'm going to work on that.
I will some day post a design for the original poster and you guys
can all tell me how terrible it is and get more of that out of your system.
Like lots of you have in the past.

I'm guessing a few people did learn from this (at the minimum lively) thread.
If it will make you guys go back to all getting along I will do you the favor of
never returning. Or change my name again and try to bite my tongue.

[dlr]

Given all these, you were able to push the tweeter low to meet up with the woofer off axis. However remove any one of these, and when you have differing off axis dispersion to deal with, IME its still better to use a soft knee and wider overlap.

I didn't address this in my first response. While I agree that when it's possible to use a wide overlap that it can provide a smoother off-axis and power response. When you can select the drivers that allows for selecting a match that allow is. For my 2-way above I was given the drivers by zaph on the condition that I publish a design. I went farther and added the detail of my design process for it. You really can't do a low slope crossover primarily because that midwoofer has a rather nasty peak/breakup area that will be too high on-axis. Higher order slope was necessary for that one. I added a droop into the target after initial auditioning, but I add that to the target, usually leaving one or the other individual drivers fixed to maintain a semblance of the target function. I don't recall specifically, but given the need to keep the midwoofer breakup down to at least -20db, I probably only allowed the tweeter to vary which would lower it's output, therefore limit to some degree it's off-axis flare and the total power response.

With a lot of the average drivers used, likely based on cost, this is a common problem I'm sure. I've not had any luck with that sort of driver and getting what sounds good to me if I used low slopes. Then there's the problem of tweeter power handling that has to be considered. Not any easy compromise to decide.

dlr

[bill poster]

We are a community of speaker enthusiasts, people come here to learn and share in a friendly and polite environment, so I would say it is quite rude to call someone's design wrong, bad, poor choices, etc simply because they have made design decisions that don't agree with your design opinions.

It needs to be said, because of the above PE lost alot of knowledgeable people who were generous and happy to answer questions daily. So it doesn't sit well with the rest of us who want to learn about the hobby if a few people mess up the PE community spirit

[dlr]

It's an SB26 that measured higher than the manufacturer's specs, about 850Hz. You can estimate it using that.

dlr

[xmax]

About how many?

[dlr]

Is the tweeter about 50dB down at Fs? Just curious.

No

dlr

[xmax]

Is the tweeter about 50dB down at Fs? Just curious.

[dlr]

Dave, this is a response to your post 247. Somehow that got lost in the edit.

True except for the low driver, at least for purposes of this thread discussion. The OP originally asked about a tweeter to match an SB 5" driver as was my midrange and the design by Jeff that was criticized without having been heard by xmax is a 2-way with an SB12 NRX, a 4" driver. Which makes Jeff's crossover even more reasonable. I wouldn't expect much tweeter flare in comparison to the off-axis of a 4" driver crossed as he did.

But I wouldn't call an LR8 to be a brick wall filter and the waveguide is really rather limited.

I had thought the DXT (95db, rated by Seas down to 2K) to be the equivalent motor as the 27TDFC (90db), but that one is rated down to 1500Hz and higher power. I may swap out one of my other standard tweeters for comparison, but I've been pleased with the system as it is. I auditioned it at my last DIY event and pushed it as hard as anyone wanted to hear it, higher than I usually do. No one complained about distortion or unpleasantness at all. I heard none. I'm of the opinion that distortion of a good tweeter is a lot less of an issue than many believe, at least with typical music content.

These graphs are for my Chameleons, the 2-way with 6.5" SB woofer and 1" SB tweeter. They can be generated in WinPCD. The calculations are for various polar responses as indicated for the crossover and driver variation with polar vectors. In WinPCD you examine a single off-axis point or generate these graphs. The off-axis uses a modified Bessel function for driver directionality. Simplistic, yes, but at least it provides a reasonable idea. It doesn't have any diffraction, so the step isn't part of it. Maybe one day. But it does show the crossover integration in the polar response reasonably well. I added in a Bessel rolloff as well to the result of the uncorrelated power response calculations using the 45 degree angle as a guesstimate for the directionality influence.

The horizontal is -90 to +90 as is the vertical. The system plot includes the calculated response for a system assuming the on-axis response to be non-correlated for power, similar to Jeff's PCD. The hemispherical graph shows the integrated response for each ring of a set of concentric circles at 5 degree intervals and the total front hemispherical response. Taken together they define a hemisphere at 1m radius.

The power response calculated by simply considering all driver responses to be non-correlated isn't all that different from a set of hemispherical calculations integrated over the front hemisphere.

I can't (yet) export any of the calculated power curves, but I set the graphs roughly equivalent screen sizes.

dlr

[JRT]

I like tilted baffles because the "on axis" response is closer to the 30 degree cone average and eqing close to flat on axis creates a much more balanced tone in room than when eqing on axis flat for a box with a vertical baffle.

Reminds me of something little different, but maybe of interest to you. Take a look at entry number 42 on D.B.Keele's webpage of AES papers. I will try to link that below, but this board software doesn't always play well with my old tablet.

edit: Well that did not work, so trying hand coding the link.
D.B.Keele's AES papers (see entry number 42):

http://www.xlrtechs.com/dbkeele.com/papers.htm

I noticed Horbach-Keele linear phase digital crossover filters for pair wise symmetric multi-way loudspeakers mentioned here in the article directly above a different unrelated article about DBK's CBTs.
http://www.linkwitzlab.com/Constant_...#Horbach-Keele











.

[JRT]

Power response is everything...

I will repeat what John said... No.

While I expect that you will not accept this sound advice, I am suggesting that you should buy and read with an open mind, the 3rd edition of Dr. Floyd E. Toole's book, "Sound Reproduction, The Acoustics and Psychoacoustics of Loudspeakers and Rooms". Turn off the confirmation bias filters and set aside what you think you already know, and learn.