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Hivi 3.1A DIY Speaker With Sehlin Mod Review

amirm

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#1
This is a review and detailed measurements of the Swan Hivi 3.1A DIY Speaker kit with modified crossover by Sehlin Sound Solutions. It was kindly sent to me by @Mudjock as tested. The kit by itself goes for US $300 including Prime shipping. Unusual for a speaker kit, it comes with everything you need including the speaker box. As built the response is too hot in the tweeter (I think) and hence the mod: https://sites.google.com/view/sehlin-sound-solutions/hivi-diy-3-1-modifications

I must say I like the white finish on a DIY speaker better than black:

HiVi - DIY 3.1 Bookshelf Speakers Stereo Review.jpg


Please don't mind the little nicks. The crossover had come loose in shipping and I had to take the speaker apart to affix it.

The mid-range throw me off as I first thought those two little wires are debris so I proceed to try to grab then with my needle nose pliers! Fortunately I realized in time and didn't try to pull them off. So if you have grabby hands around your household, you better make a grill or buy a different speaker.

While I was in there, I took pictures of the drivers and crossover:

HiVi - DIY 3.1 Bookshelf Speakers Woofer Stereo Review.jpg


HiVi - DIY 3.1 Bookshelf Speakers Midrange Stereo Review.jpg


HiVi - DIY 3.1 Bookshelf Speakers Tweeter Stereo Review.jpg


HiVi - DIY 3.1 Bookshelf Speakers Crossover Stereo Review.jpg


The tweeter wires had come off also. I thought I tighten the clips before sliding them on and was disappointed by how soft the tabs on the tweeters were. They started to bend and felt like they would fall off you did that once or twice.

FYI despite my addition of double sided tape (admittedly low quality ones), the crossover came loose again. So best to think of a more solid way to mount them.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I used over 800 measurement point which was enough to compute the sound field of the speaker within 1% error except region above 12 kHz or so. This may have caused a bit more of a steep drop off in that region than reality.

Temperature was 75 degrees. Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

HiVi - DIY 3.1 Bookshelf Speakers Spinorama CEA CTA 2034 Frequency Response Measurements.png


On-axis response is not ruler flat but not too bad either. I tend to like areas I can pull down in upper bass than needing to push them up.

Off-axis response shows more clearly a dip in mid-range response:

HiVi - DIY 3.1 Bookshelf Speakers Spinorama CEA CTA 2034 Early Reflections Frequency Response ...png


You can see this more clearly in near-field response of all the drivers/port:

HiVi - DIY 3.1 Bookshelf Speakers Driver Near-field response  Measurements.png


Low response of the midrange between 1 and 2 kHz has an unwanted shelf causing lower energy there.

Predicted in-room response is one that we could guess:

HiVi - DIY 3.1 Bookshelf Speakers Spinorama CEA CTA 2034 Predicted In-room  Frequency Response...png


I was impressed by low levels of distortion:

HiVi - DIY 3.1 Bookshelf Speakers Relative Distortion  Measurements.png


HiVi - DIY 3.1 Bookshelf Speakers THD Distortion  Measurements.png


Distortion in bass usually goes off scale but here is very well managed until we drop to below 40 Hz.

Beamwidth is typical but somewhat uneven:
HiVi - DIY 3.1 Bookshelf Speakers Horizontal beamwidth response  Measurements.png


Here are the directivity measurements:

HiVi - DIY 3.1 Bookshelf Speakers Horizontal Directivity response  Measurements.png

HiVi - DIY 3.1 Bookshelf Speakers Vertical Directivity response  Measurements.png


EDIT: here is the impedance graph:
HiVi - DIY 3.1 Bookshelf Speakers Impedance and Phase  Measurements.png


Speaker Listening Tests
Out of the box, the speaker sounded very good but with tonality that is a bit on the bright side. Upper bass can also be a bit tubby just like the measurements indicate.

I usually have an EQ at 100 hz for a room mode but here, it actually helped the response so I turned that off. I then put in a dip at 700 and 3000 Hz (1 and 2 dB respectively with Q of 2). The latter was effective across all content. The 700 Hz was a matter of taste.

I was most impressed by how clean the Hivi 3.1 could play. I could push it up to reference levels without a hint of distortion with body sensations to boot! My "speaker killer" tests nearly did not impact the Hivi. It did not try to reproduce the deep bass too much and this was its savior. No bottoming out. No static. Most excellent.

Helped with my room mode at 100 Hz and tiny bit of EQ, this speaker produced delightful sound, albeit with still some slant toward highs. The subjective performance pushed my my preference one notch relative to measurements.

Conclusions
I had low expectations going into this review and boy, was I surprised. No, there is no perfection here and without EQ, you may find the sound a bit annoying. But small amount of EQ fixes most of that and delivers a speaker with impressive dynamics and very balanced design. It is able to outperform many budget speakers in its ability to play loud and not bottom out/distort.

Assuming you do use EQ and want the sanctification of building a DIY speaker, the Hivi 3.1 with Sehlin gets my strong recommendation!

Note that if your room doesn't provide the bass enhancement that mine did, your experience may not quite match mine. I can only report on what I hear in the same setting as other speakers which happened to help this speaker.

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As always, questions, comments, recommendations, etc. are welcome.

$440. That was the cost of my helper pulling weeds in the garden which I would normally do but did not have time due to testing audio gear. I know most of you are as cheap as me but come on, I can't shoulder all of this cost so please donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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Lorenzo74

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#3
Thank you Amir! again a top speaker review.

just wonder if the ”small amount of EQ” can be quantified and engineered into the XO so this could become a stand alone V.Good speaker ASR certified.
why they didn’t do it accordingly?
my Best
Lorenzo
 

thewas_

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#5
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.
 

restorer-john

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#7
@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.
 
OP
amirm

amirm

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Thread Starter #10
Thank you Amir! again a top speaker review.

just wonder if the ”small amount of EQ” can be quantified and engineered into the XO so this could become a stand alone V.Good speaker ASR certified.
why they didn’t do it accordingly?
my Best
Lorenzo
It is harder to do small EQ adjustment using passive parts. They are expensive to boot. Here are my EQ settings by the way:

1599263540870.png
 
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amirm

amirm

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Thread Starter #11
@amirm I can't believe you tried to pick off the voice coil lead out wires for the mid dome...
Hey! It was in my garage at night. Eyesight is not what it used to be!
 

KaiserSoze

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#15
@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.
If he had done that, man that would have been embarrassing!
 

KaiserSoze

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#16
It is harder to do small EQ adjustment using passive parts. They are expensive to boot. Here are my EQ settings by the way:

View attachment 81444
I think it would not be difficult to design/construct close approximations with a pair of passive, shallow notch filters. The Q wouldn't be an exact match, so it wouldn't be quite as good, but it would be close enough.
 

KaiserSoze

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#17
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.
 

richard12511

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#18
For those willing to DIY, this looks like the new budget king for those who need louder than the pioneer can handle. It looks quite a better than the 305p, to my eye. This is cheap enough and good enough that it makes me want to try DIY.
 

GDK

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#20
For those willing to DIY, this looks like the new budget king for those who need louder than the pioneer can handle. It looks quite a better than the 305p, to my eye. This is cheap enough and good enough that it makes me want to try DIY.
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.
 
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