Hivi 3.1A DIY Speaker With Sehlin Mod Review

[peanuts]

i couldnt find the crossover frequencies. this isnt a real dome mid is it? like the wharfedale`s come in at 1.3-1.4khz. that would be treble, not midrange in my opinion. lots of 1" compression drivers cross lower than that and are never considered mids.

 

[Chromatischism]

i couldnt find the crossover frequencies. this isnt a real dome mid is it? like the wharfedale`s come in at 1.3-1.4khz. that would be treble, not midrange in my opinion. lots of 1" compression drivers cross lower than that and are never considered mids.

It's in the middle of the woofer and tweeter

 

[Billy Budapest]

I would like to take a little time to provide more information and address a few questions and comments.

First of all, many thanks to Amir for the review. I put him through a lot for this review. I freely admit that most of the speakers I build can best be thought of as prototypes. Drivers are frequently connected with removable connectors as opposed to solder. I've had a last minute defective driver replacement at a DIY event/competition and it's a lot easier than bringing a soldering iron... Crossover boards are often mounted in such a way to be removable for future tweaking. All of these issue came home to roost for this review as Amir's first comment was that something was rattling inside the cabinet, which turned out to be the crossover board that came loose during shipping. When Amir reattached that and ran his tests, it was apparent that the tweeter had no output, so he had to open them back up, reattach the tweeter wires, and remeasure. I wouldn't have blamed him at all for sliding these down on the Panther scale, but he did the opposite. If I send anything in the future, I will at least make sure the assembly methods are fit for commercial ground transportation.

HiVi deserves all the credit the cabinet design and tuning that protects the woofer and the midrange, enabling distortion to stay under control at high output. They picked a good set of drivers for this kit, which is what initially interested me, as I had previously heard all of the drivers (and worked with the midrange on another project).

I always thought it was odd that they chose to design a crossover with such a rising response. This is straight from the swanspeakers website.
View attachment 81674

I saw an assembled pair for sale on our local craigslist and decided that it would be fun to see if they sounded like the manufacturer's response curve indicated and see what it would take to flatten the response curve. I step through the process on the Midwest Audio Club forum

MAC/DIY HiVi DIY 3.1 Post

I summarized the results on my Sehlin Sound Solutions page. The speakers reviewed include the option 4 "perfectionist option" crossover.



This is certainly true. There are a number of reasons for that, but the name is perhaps a bit misleading. I set out to see if simply tweaking resistors could fix the crossover, but that wound up not to be the case. Although I could bring the mids and highs in balance with the bass, the response was very uneven as shown in options 1-3. For option 4, I constrained myself in a couple of ways:

1. Add no complexity to the assembly process versus the original kit
2. Keep the cost low

These considerations meant that whatever I did would allow use of the circuit board that comes with the kit and would not touch the most expensive components (larger inductors and capacitors). The resulting mod only adds about $25 in parts to the $299 kit.

View attachment 81679

I was very relieved that the on axis response and impedance (actual driver measurements with a simulated crossover applied) closely matches the on axis response from the Klippel NFS.



It is possible to tweak the crossover to bring the level down a dB or two where it is elevated. The changes I would recommend include

1. Increase C5 (in the woofer circuit) from 47 uF to 68 uF.
2. Increase R2 from 2 ohms to 3 ohms in the midrange circuit
3. Increase R1 from 5.6 ohms to 6.8 ohms (7 ohms would be fine depending on which is available) in the tweeter circuit.

View attachment 81685

I'm not sure if that will sound better in all rooms as part of the reason I set the mid and tweeter level where I did was to avoid the upper bass region from standing out and sounding too "tubby"



I have long been a fan of dome and other unusual mids. Here is a recent picture of my listening rotation.

View attachment 81683
The 3 way's with the dome mid are an unpublished design because the 3" Tang Band dome mid is no longer available to DIY'ers.

View attachment 81684

This is the Indium 7 design which was one of my Parts Express Design Team projects and still can be built. It uses the same mid as the HiVi DIY 3.1A (except for a slightly different flange).

A little off-topic: I saw a reference in the Midwest Audio Club link to a meetup in Grinnell—I assume that is Grinnell, Iowa, and not Grinnell, Kansas. As a Grinnell College alum, that warmed my heart!

I am seriously thinking about buying this kit as a Covid project. I get the component swaps in the perfectionist crossover mod but I don’t really understand the mod to the tweeter filter circuit. Maybe I’ll have one of my more tech-savvy friends built the crossover for me.

One question: what would be the effect of dampening the cabinet either with polyester fill or foam or cotton or wool batting attached to the inner surfaces? Would doing that necessitate further changes to the crossover? Thanks!

 

[Mudjock]

I don’t really understand the mod to the tweeter filter circuit.

The mod to the tweeter circuit is just component swaps, too. The only difference is that all 4 components are swapped.
R1 goes from 1.5 ohms to 5.6 ohms
C1 goes from 3.3 uF to 1.5 uF
L1 goes from 0.1 mH to 0.15 mH
C2 goes from 6.8 uF to 2 uF

 

[Mudjock]

what would be the effect of dampening the cabinet either with polyester fill or foam or cotton or wool batting attached to the inner surfaces?

The kit comes with some "acoustic cotton stuffing", which is how the speaker was tested. Changing to a different material or different amount of material can impact the tuning frequency of the port. If the change is large, it may impact the tonal balance. If you want experiment, I would recommend that you keep the original stuffing so that you change back if the new material winds up having a detrimental effect.

 

[Mudjock]

Zeos raved about these, I wonder how the non-mod would sound

I watched at least one of those reviews and he had headphone ear pads covering the tweeters...

 

[radio3]

It would be nice to know how the Wharfedale look-alike compare in performance. I like the rounded edges on the enclosure, but is it as well braced and made with as good quality material? The tweeters also look different.

 

[Billy Budapest]

It would be nice to know how the Wharfedale look-alike compare in performance. I like the rounded edges on the enclosure, but is it as well braced and made with as good quality material? The tweeters also look different.

Wharfedale owns its own manufacturing plant and makes all components top-to-bottom, like HiVi/Swan, so I expect the similarities to be only skin deep.

 

[BYRTT]

.....It is possible to tweak the crossover to bring the level down a dB or two where it is elevated. The changes I would recommend include

1. Increase C5 (in the woofer circuit) from 47 uF to 68 uF.
2. Increase R2 from 2 ohms to 3 ohms in the midrange circuit
3. Increase R1 from 5.6 ohms to 6.8 ohms (7 ohms would be fine depending on which is available) in the tweeter circuit.....

Thanks heads up and all the hard work your XSim model curves is traced below and overlaid Amir's curves..

Difference in above traced curves, the pure option-4 verse tweaked option-4 can be modeled into Amir's spindata as in below animation, objective looks good on paper, could a squize lower value of woofers L4 fill up the 300Hz dip..?..

 

[Rotary Transformer]

I waited for this review so long, eventually, I could hand my money to HiVi with no more hesitation.

 

[Mudjock]

could a squize lower value of woofers L4 fill up the 300Hz dip..?..

I think if L4 is allowed to vary, the dip could be filled in. The capacitor and resistor values may also have to change. That's something I will investigate further.

 

[geoemm]

Not soft dome , but kinda similar design
Fishhead audio resolution 1.6 (from Germany)

 

[maltux]

I sent Frank Hale a link to this review. Maybe he will chime in.

 

[lashto]

Not soft dome , but kinda similar design
Fishhead audio resolution 1.6 (from Germany)View attachment 81797

€799 list price. Somewhat reasonable for a fully built version with warranty/service. Only found measurements for the full-size 2.6 version, seem to be quite similar to the kit version

 

[thewas]

Here are (similarly good) measurements of the bookshelf version https://www.hifitest.de/test/lautsprecher_stereo/fishhead_audio-resolution_16_bs_19274

 

[rfeng]

This DIY kit priced at ¥3500 or $500 in China, nobody talks about it. In comparison，a pair of Hivi D3.2 MKIII tower can go lower than ¥3000. The weight is 30kg each. Wondering how it performs. @WolfX-700, do you review speakers?

 

[stevenswall]

Is the Sehlin crossover layout available?

I have these speakers with the ScottS "perfectionist" crossover in them, and I think there should be metal mounting rods for the crossover board but I don't see them on this one.

Shoe goo also helps things not rattle or detach... Used that in some areas I was worried.

Kudos to the finisher. Mine are white too.

 

[Chromatischism]

^ I love your TV stand

 

[BYRTT]

Is the Sehlin crossover layout available?.....

Could be wrong here and then simply ignore message but have a feeling you mean schematic, not real board layouts but pictures of board can be seen in post 1 Amir's picture looking into the enclosure and member ROOSKIE shared a board picture into post 38, link to schematic Amir shared in first few lines of post 1 and its the option-4 there in that link, myself get member Mudjock here is member ScottS over there so lookup Mudjock posts in this thread to get best updates and links that probably also include layout..

 

[Mudjock]

Could be wrong here and then simply ignore message but have a feeling you mean schematic, not real board layouts but pictures of board can be seen in post 1 Amir's picture looking into the enclosure and member ROOSKIE shared a board picture into post 38, link to schematic Amir shared in first few lines of post 1 and its the option-4 there in that link, myself get member Mudjock here is member ScottS over there so lookup Mudjock posts in this thread to get best updates and links that probably also include layout..

This is correct, Sehlin = ScottS = Mudjock. The ScottS perfectionist crossover is what was tested.