HiVi/Swans DIY 2.2A (crossover modification/upgrade)

[Vidgamer]

Originally Posted by Tvrpeppe

Hi,
....
The cabinets are made in 19mm mdf with 0.7 mm walnut rot veneer glued to the surfing with epoxy. The surface finish is made with about 0.7 to 1.0 mm of clear epoxy covered with 3 to 4 layers of polyuretan lacquer.

Those look awesome! Much nicer than my crappy paint job. I don't have the patience to do veneer, but it does look better.

I don't have any measuring equipment, but I can't hear that the speakers lack in bass response. They beat my modified B&W 601 s3 by far in bass and clear sound. But interested in the modifications you guys have suggested I tried to replace the coil for the midwoofer to a 2.4 mH 0.51 ohm coil and I think the sound got a little more laid back in the midrange.

I can't say that I noticed the midrange being more laid-back, but the bass seems slightly stronger, but still not boosted. Which is good to me. I don't like the boomy-bass sound. When I first measured the speakers with the stock crossover, it looked to me like the bass was down about 3db or more. Now, it seems pretty even with the midrange.

The difference is a lot more subtle between the two inductors than I expected, I guess, with music, but it definitely measures differently. I think the efficiency is better, now, for one thing. From the measurements, I'm guessing the bass improved around 3db. I can see where the stock crossover might be fine for some, but hard to ignore the weak bass. Placement could also make a big difference. The stock setup sounded good and clear, but a bit thin. Even with the 2.1SE mods, it's still a bit high in the treble area. (Measured, it looks like it might be +3db or so?) When time permits, I'd like to retest using REW which may give me more helpful charts.

At rather high levels I think there is some kind of distortion in low treble or high mid, so I have ideas of changing the cap for the tweeter to a smaller value, 5.6 uF or 4.7 uF as in the 2.1 se. The data sheet for the tweeter say that the tweeters frequency response is 2500 Hz and up but in a another part of the data sheet say flat responce from 1500 Hz and up. And in some forums people say that this tweeter shouldn't be used lower than 2500 -2700 Hz, do you guys have any thoughts on this?

I think it'd be helpful to get Allex's files and use Xsim to play with different values for the crossover parts. I just haven't taken the time to do that. When I have a lot of free time, I'd like to play with that.

In general, I would think tweeters should not be crossed-over too low. It's not obvious to me where the crossover point is, thus the desire to get Xsim working. I'm a bit confused as to why there's a difference there in the 2.2DIY and the 2.1SE, and hopefully the xsim plots would clarify that. I'm wondering if the mids actually are raised that much with the .5ohm that it means the tweeter can then be crossed higher to get out of the way? Also, Xsim should let us know how much bass we really gain out of that inductor change.

[Tvrpeppe]

Originally Posted by AllexKirilov

Below you can find the files from my measurements that I used for the simulations. You might be interested to use them until you get your microphone. The file “HiVi D6.8B-IIB & HiVi Q1R.frd” represents a measurement from both drivers in the speaker cabinet without any crossover. I used this file to determine the relative delay between the drivers - something that is quite often neglected. The ZMA files are taken with DATS v3 as a “free-air measurement”. I hope that would be of help.

-@llex

I have downloaded the Xsim software this morning, it say it is something wrong with .frd and .zma files when I try to load them in to the speaker tuning in the software.

//Peter

[AllenB]

Can you zip the files and post them here.. or change their extension to .txt and post them.

[Tvrpeppe]

This is the zip file I downloaded and tried to use the files from, after extracting the whole folder.

[AllenB]

The files seem to be OK.

[Tvrpeppe]

Thanks, probably I have to read how to use the software

[AllenB]

Right click the driver and select tune. Then bring in the files.

[Tvrpeppe]

Originally Posted by Vidgamer

There is still this dip at 3k. I also tried it with the original 6.8 mfd caps, only changing the woofer’s inductor, and that dip was still there. I couldn’t tell much difference between the two, really, but decided to stick with the Swans 2.1SE design, and ended using the new caps. Will listen for a while, but happy to have the missing bass.

I got Xsim to work so I have been playing around a little with different crossover configurations tonight, to get rid of the dip at 3k you should change the polarity on the tweeter. You might get a small hump instead but that is possible to correct by increasing the value of the 1.5 ohm resistor to 5.6 ohm. The increased value of the resistor will also give a little more of bass.

Another thing that gives you a more fullbodied sound is to chamfer the hole for the midwoofer on the inside of the baffel, check the link to Gravesens little test that is in one of my previous posts. If I get the time during this weekend I will try out a change on the crossovers in my speakers.

[Vidgamer]

I figured the dip was around the crossover area, but I guess I shouldn't be too surprised if they are out of phase, since changing the cap didn't seem to make much difference. Interesting. Why didn't either of the Swans/HiVi designs flip the polarity? If you have basically a 2nd order crossover, isn't it normal to reverse the polarity of the tweeter? I'm going to look at the diagrams again.

I happen to have 4ohm resistors handy. If I can get Xsim going, I'll see if that would work. Since I already changed out the cap, the bump may not be as significant anyway.

Chamfering sounds like a good idea, but not sure I want to fool with that, now that everything is assembled. (Seems like you'd want to try to do it when cutting the holes.) Besides, I'm not sure the 18mm or 19mm of our baffles is that significant. His examples start at 22mm, so we're already going to do better than that, plus the speaker seems pretty open in the back. Seems less of a concern to me, but could be an interesting experiment. Try to measure before and after!