Hivi 3.1A DIY Speaker With Sehlin Mod Review

[hex168]

I am glad to see this speaker tested because I have been curious about it. When I look at the graphs the thing that stands out to me, as the notable weakness of this speaker, is the narrowness of the listening window in the vertical plane, to avoid the nulls caused be interference between the big dome and the ribbon tweeter. The window appears to be about +/- 20 degrees at best. This is attributable to the integrated, combined effect of the high frequency of the crossover point (in the neighborhood of 5.5 kHz apparently) and the spacing between the mid-tweeter and the tweeter. The spacing looks like it is maybe about 4", and the wavelength at 5.5 kHz is about 2.5". I can't help but think that it would be better if the ribbon were a simple 3/4" tweeter with a very small flange. Or maybe a 1" tweeter so that the crossover point could be lower. But it is without doubt an excellent speaker and one that I would seriously consider buying, because I just like 3-way speakers.

I'm curious, looking at the horizontal polars, why HiVi did not use their RT1C-A planar tweeter instead of the Rt1.3 B.

 

[amirm]

@amirm, do we have an impedance measurement?

Oops. Just added to the review:

 

[Billy Budapest]

Now that you have tested Swan’s, you gotta test their Chane stablemates. At least, Lane used to be the importer for Swan.

Chane has a really devoted base of support and also a large number of vehement detractors. Sounds familiar these days. Anyway, would like to see if they live up to the hype.

https://www.chanemusiccinema.com/

 

[Kustomize]

So glad DIY speakers are getting tested! I remember when there was a discussion going on about whether the Zaph 5.2 should be added to the tables for comparisons!

DIY is really showing promises!

 

[Ericglo]

Which option was used in the crossover?

 

[KaiserSoze]

I'm curious, looking at the horizontal polars, why HiVi did not use their RT1C-A planar tweeter instead of the Rt1.3 B.

I recall that I wondered about that same question when I was looking into this kit speaker a month or two ago. At least with the other tweeter you mentioned you would get the benefit of better horizontal dispersion. The Rt1.3 B or whatever it is does not likely do anything that a half-decent dome wouldn't do just as well. Maybe it's a little smoother in the highest octave, above 10 kHz, where I can't hear much anyway. Either way though, the planar tweeters aren't doing anything to avoid the nulls in the vertical polar plane. No worse than a typical dome with a huge ferrite magnet and huge flange. I don't see as how the supposed benefits of any of the planar tweeters, vs. a good dome, is genuine or significant. As I look at it the tweeters that offer real advantage are the neodymium domes with small flanges that can be pushed up very close to the midrange. That's assuming no waveguide, which increases the vertical separation, so the advantage of a neo dome with small flange probably does not materialize with 2-way speakers, only with 3-way speakers where the omission of the waveguide can be justified on the basis of the increase in the vertical axis listening window. That's my thinking anyway. But I don't see any fundamental drawbacks to concentric midrange-tweeter configurations, and I see benefits in the improvement of the listening window in the vertical polar plane (defining the vertical listening window as the angular separation between the nulls occurring in connection with interference between the midrange and tweeter in the frequency vicinity of the crossover).

 

[amirm]

Which option was used in the crossover?

It is option 4.

 

[RickS]

@amirm how about fixing the Sahlin mispell in the thread title please?

 

[maltux]

I agree. Could anyone give me an estimate of approximately how long it would take to put these together (you can safely assume that I have zero skill in this area)? I am always on the lookout for fun projects to do with my son.

Video on the assembly by Frank Hale

 

[GDK]

Video on the assembly by Frank Hale

That‘s exactly what I was after. Many thanks for that!

 

[Ericglo]

It is option 4.

How much does that option add to the cost?

 

[Mudjock]

I checked on that this morning. Using Dayton Audio basic resistors and capacitors as built for the pair reviewed, the cost is $25 to mod a pair.

 

[Xyrium]

Another cool compact 3 way, keep 'em coming! Thanks Mudjock!

 

[RickS]

Video on the assembly by Frank Hale

Great set of videos but the crossover one is a bit light for a newbie. If you know how to solder, this is easily a 2-day project without finishing the cabinet. Finishing the cabinet might take a day or a week (or more) depending on your experience.

Really like the crossover mounting system used AND that he has you test the crossover before you install.

 

[ROOSKIE]

@amirm I can't believe you tried to pick off the voice coil lead out wires for the mid dome...

With a really nice cabinet, they could be quite the bargain for a college kid or DIYer. I couldn't put that white painted thing in the house as it is. Great review.

Because there are no round-overs, one could easily apply veneer. These could be made to look very rich for a basic DIY level of skill.

 

[richard12511]

@amirm , based on these results, I'm very interested in making this my first DIY project. Looking at the modification link you posted, the modded version does look much more neutral, but I have no idea how to build that crossover. Do you have instructions on how to build the speaker with the modded crossover?

 

[amirm]

@amirm , based on these results, I'm very interested in making this my first DIY project. Looking at the modification link you posted, the modded version does look much more neutral, but I have no idea how to build that crossover. Do you have instructions on how to build the speaker with the modded crossover?

I did not build this. But quickly looking, you buy the kit from Amazon, and then the parts for the mod. The mod parts replace the original parts so there is nothing to modify per se.

 

[ROOSKIE]

@richard12511
I hope I have this correctly as I have not built this set.

https://imgur.com/a/GvjB52R

 

[Mudjock]

@amirm , based on these results, I'm very interested in making this my first DIY project. Looking at the modification link you posted, the modded version does look much more neutral, but I have no idea how to build that crossover. Do you have instructions on how to build the speaker with the modded crossover?

The good thing about the mod is that the circuit board that comes with the kit can be used. 7 of the 12 components are changed. I think someone posted a picture of which components are changed. If I can find it, I will post it. Otherwise, I will have to make one.

 

[KxDx]

The good results don't really surprise me, as the 1970s typical 3-way design with a compact mid dome gives relatively smooth directivity and low distortions in the psychoacoustic most important mid region, I have many such loudspeakers in my vintage loudspeaker collection and similar to this case with a bit of EQ they can still sound competitive today.

I'm working on bringing a pair of Allison CD9's back to life. Really looking forward to the day they are ready.