This is a review and detailed measurements of the Selah Integrity DIY Speaker Kit. @
Selah Audio designed this kit in memory of DIY designer, Jeff Bagby, who sadly passed away due to Covid-19. The Kit was kindly built by
@Rick Sykora. Meniscus Audio will be selling the kit and a portion of the proceeds goes to family of Jeff Bagby. The kit cost starts at $630 plush shipping for a pair.
This is a three-way design and built out of ultra dense and thick MDF:
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As you can see, there is an oval passive radiator in the back. It was a pleasure to have a pair of binding posts where I could get my fingers in there.
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.
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:
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The on-axis response looks very good. The only exceptions are the perturbation around 1.7 kHz and a bit of rising energy in the upper end. The dip at 1.7 kHz remains in off-axis as well:
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Resulting predicted in room response is what we already know:
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So very good overall.
Digging into the source of that dip it appears to be the bottom end of the midrange driver:
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Speaking of mid-range, it seems to be playing louder than it can without distortion:
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I don't usually see correlations between frequency response errors and THD percentage but we have one here at 1.7 kHz.
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Impedance is around 5.5 ohm which is higher (better) than typical small speaker, putting less stress on the amplifier:
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The mid-range provides wide beamwidth in the mid-range:
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Here is the same as a heatmap:
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The 3-way design makes vertical placement less critical:
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And here is the waterfall:
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Speaker Listening Tests
Having seen the measurements before listening, I expected the sound to be good but it wasn't! It sounded muffled in the mid-range. Fortunately I quickly realized I had the EQ on from last test I was doing so turned that off and all was well with the universe.
The experience was very good albeit with a touch too much upper end energy. I put it this way as opposed to saying "bright" as the treble response is not high enough to be annoying. It was close enough that I did not bother to EQ but you may want to.
I toed the speaker out a bit and while that did reduce the highs a bit, I had a preference for the more clear direct sound. Anyway, it is something you can play with.
The Integrity is very inefficient by the way requiring me to turn up the volume to very high levels. Fortunately it handled the power well and could get loud despite a single speaker playing.
My subsonic bass test tracks which I call "speaker killers" earned their designation though causing massive distortion. You better have a filter for such bass notes or not have as powerful of an amp as I have. Fortunately the woofer recovered as if nothing had happened and continued playing.
Note that 99% of my music and even those with heavy bass don't have the subsonic energy that cause the problem above.
Conclusions
I must say, I was very nervous going into this review. The work is for a good cause but so is transparency in speaker reviews. I had my fingers crossed that it would measure and sound well. What a relief it was that it did both.
I am happy to recommend the Selah Integrity DIY design Kit. I hope you all support the effort by purchasing them and getting experience with building your own speaker and doing some good in the process.
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As always, questions, comments, recommendations, etc. are welcome.
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