DIYSG HTM-12v1 Speaker Review

[hardisj]

This is copy/pasted from my website. Therefore, there may be some formatting things that go awry when pasted here. Feel free to view the review natively on my site linked below. Otherwise, enjoy it here!
https://www.erinsaudiocorner.com/loudspeakers/diysg_htm12v1/



DIYSG HTM-12v1 Speaker Review

• Tuesday, May 18, 2021

Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.
However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc.) - please watch the below video where I go more in-depth.



Information and Photos
The DIYSG HTM-12v1 is a DIY design from Matt Grant which was/is available in kit form from DIYSG.

Note the distinction of this model is “v1” as there has since been an update to this speaker design which was released in early 2020. Therefore, this review is more for educational purposes and hopefully will help users and designers alike understand the objective performance in the highest resolution possible as current available measurements are a mixture of quasi-anechoic methods and thus have low resolution / high smoothing, insufficient to show problematic areas where anechoic measurements excel.

The HTM-12v1 is a 2-way loudspeaker featuring a SEOS-15 waveguide with Denovo DNA-325 and an Eminence Deltalite 12-inch woofer. (These specific parts could be different model numbers; this was the best information I could find and I will update this section if necessary).

A kit for a single speaker (including everything sans enclosure; except for front baffle) was approximately $330 (I think).

These speakers were loaned to me by their owner, who built them from the kit. There are no physical or electro-mechanical issues and this unit is a good sample, representative of what one would ideally build from the kit.

CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:

The reference plane in this test is just below the tweeter, per the designer, Matt.

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:

Early Reflections Breakout:

Estimated In-Room Response:

Horizontal Frequency Response (0° to ±90°):

Vertical Frequency Response (0° to ±40°):

Horizontal Contour Plot (not normalized):

Horizontal Contour Plot (normalized):

Vertical Contour Plot (not normalized):

Vertical Contour Plot (normalized):

Additional Measurements

Impedance Magnitude and Phase + Equivalent Peak Dissipation Resistance (EPDR)

For those who do not know what EPDR is (ahem, me until 2020), Keith Howard came up with this metric which he defined in a 2007 article for Stereophile as:

… simply the resistive load that would give rise to the same peak device dissipation as the speaker itself.​

A note from Dr. Jack Oclee-Brown of JBL (who supplied the formula for calculating EPDR):

Just a note of caution that the EPDR derivation is based on a class-B output stage so it’s valid for typical class-AB amps but certainly not for class-A and probably has only marginal relevance for class-D amps (would love to hear from a class-D expert on this topic).​

On-Axis Response Linearity

“Globe” Plots
These plots are generated from exporting the Klippel data to text files. I then process that data with my own MATLAB script to provide what you see. These are not part of any software packages and are unique to my tests.
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.

Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.

Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:

Harmonic Distortion at 96dB @ 1m:

Harmonic Distortion at 102dB @ 1m:

Near-Field Response
Nearfield response of individual drive units:

Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:

1. 76dB at 1 meter (baseline; black)
2. 86dB at 1 meter (red)
3. 96dB at 1 meter (blue)
4. 102dB at 1 meter (purple)

The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.

Long Term Compression Tests
The below graphics indicate how much SPL is lost or gained in the long-term as a speaker plays at the same output level for 2 minutes, in intervals. Each graphic represents a different SPL: 86dB and 96dB both at 1 meter.
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components).
The tests are conducted in this fashion:

1. “Cold” logarithmic sine sweep (no stimulus applied beforehand)
2. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
3. Interim logarithmic sine sweep (no stimulus applied beforehand) (Red in graphic)
4. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
5. Final logarithmic sine sweep (no stimulus applied beforehand) (Blue in graphic)

The red and blue lines represent changes in the output compared to the initial “cold” test.

Parting / Random Thoughts
If you want to see the music I use for evaluating speakers subjectively, see my Spotify playlist.

• Subjective listening was mainly in the farfield at 3-4 meters in an open floorplan living room. Subjective listening was conducted at 80-95dB at these distances and occasionally higher. Higher volumes were done simply to test the output capability in case one wants to try to sit further away.
• Toy Soldiers - Resonant in the 150Hz region, her voice pops through the mix ~1kHz.
• Enjoy the Silence - Missing attack, vocals are a bit “behind” the mix; likely something in the 3kHz area.
• Higher Love - Missing that strong snare attack that I really like about this track.
• Soundstage drifts in width; i.e., “Magic” by The Cars has a mouth sound that should be on the left outside but instead is at two distinct spaces on the left; how does this match with the radiation pattern? Is the radiation uniform? Sounds varied. Looking back at the radiation pattern, this makes sense as you can see the radiation tends to shift in angle. For example, at 300Hz the radiation pattern is about 20° wider than at 500Hz before getting wider again at 800Hz to 1.3kHz and then narrowing another 20° above this and narrowing up until approximately 9kHz. This varying radiation pattern in my incredibly subjective opinion causes the soundstage to not remain consistent, meaning that if an instrument or vocal is at one place in the soundstage for the fundamental, it will be at a different location for the harmonic(s). YMMV.
• Sensitivity averages around 94dB @ 2.83v/1m.
• Obviously with an f3 of 78Hz and f10 of 53Hz, these speakers do need a subwoofer. Without the addition of a subwoofer you will find lack of fullness to tracks with low midbass (50-60Hz kickdrums, for example).
• Distortion and compression are incredibly low. In fact, the lowest I’ve measured to date, besting the $3000/pair Klipsch Heresy IV.
• No problem getting very, very loud in my large living room.
• Voices don’t sound natural; FR is quite varied and some intelligibility is lost due to the 3kHz suck out.

Support / Donate

If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute link here. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. And, truthfully speaking, help me buy lunch and maybe take my wife and kid out for dinner now and again in an effort to “apologize” for spending so much time in the garage testing all these speakers. So, if you can help chip in a few bucks, know that it is very much appreciated. Alternatively, you can use the affiliate link on my site if you want to purchase these.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.

 

[hardisj]

Oh, here is a groundplane measurement I did as a sanity check to make sure the dip below 200Hz was indeed real. Ignore the GP results above about 500Hz because the speaker was not aimed to provide anything more than LF accuracy (if you know what I mean, you know what I mean). Also, the GP measurement was gated to about 50ms or so because the house was close. Normally I measure further out in the road but didn't see the need since I only was interested in 100-200Hz region. But I didn't. Therefore, you can see a bit of a rebound at the 25Hz mark that is due to a reflection from the house.

 

[Ericglo]

LOL, I said you might be the most hated or loved person over at AVS following this review.

 

[hardisj]

LOL, I said you might be the most hated or loved person over at AVS following this review.

Well, with as much time as I have spent measuring drivers for the DIY community, hopefully those folks know that I'm only providing my reviews as a means to help and I have offered my services free of charge for any future DIYSG projects.

 

[richard12511]

This is copy/pasted from my website. Therefore, there may be some formatting things that go awry when pasted here. Feel free to view the review natively on my site linked below. Otherwise, enjoy it here!
https://www.erinsaudiocorner.com/loudspeakers/diysg_htm12v1/



DIYSG HTM-12v1 Speaker Review

• Tuesday, May 18, 2021

Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.
However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc.) - please watch the below video where I go more in-depth.



Information and Photos
The DIYSG HTM-12v1 is a DIY design from Matt Grant which was/is available in kit form from DIYSG.

Note the distinction of this model is “v1” as there has since been an update to this speaker design which was released in early 2020. Therefore, this review is more for educational purposes and hopefully will help users and designers alike understand the objective performance in the highest resolution possible as current available measurements are a mixture of quasi-anechoic methods and thus have low resolution / high smoothing, insufficient to show problematic areas where anechoic measurements excel.

The HTM-12v1 is a 2-way loudspeaker featuring a SEOS-15 waveguide with Denovo DNA-325 and an Eminence Deltalite 12-inch woofer. (These specific parts could be different model numbers; this was the best information I could find and I will update this section if necessary).

A kit for a single speaker (including everything sans enclosure; except for front baffle) was approximately $330 (I think).

These speakers were loaned to me by their owner, who built them from the kit. There are no physical or electro-mechanical issues and this unit is a good sample, representative of what one would ideally build from the kit.

CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:

The reference plane in this test is just below the tweeter, per the designer, Matt.

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:

Early Reflections Breakout:

Estimated In-Room Response:

Horizontal Frequency Response (0° to ±90°):

Vertical Frequency Response (0° to ±40°):

Horizontal Contour Plot (not normalized):

Horizontal Contour Plot (normalized):

Vertical Contour Plot (not normalized):

Vertical Contour Plot (normalized):

Additional Measurements

Impedance Magnitude and Phase + Equivalent Peak Dissipation Resistance (EPDR)

For those who do not know what EPDR is (ahem, me until 2020), Keith Howard came up with this metric which he defined in a 2007 article for Stereophile as:

… simply the resistive load that would give rise to the same peak device dissipation as the speaker itself.​

A note from Dr. Jack Oclee-Brown of JBL (who supplied the formula for calculating EPDR):

Just a note of caution that the EPDR derivation is based on a class-B output stage so it’s valid for typical class-AB amps but certainly not for class-A and probably has only marginal relevance for class-D amps (would love to hear from a class-D expert on this topic).​

On-Axis Response Linearity

“Globe” Plots
These plots are generated from exporting the Klippel data to text files. I then process that data with my own MATLAB script to provide what you see. These are not part of any software packages and are unique to my tests.
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.

Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.

Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:

Harmonic Distortion at 96dB @ 1m:

Harmonic Distortion at 102dB @ 1m:

Near-Field Response
Nearfield response of individual drive units:

Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:

1. 76dB at 1 meter (baseline; black)
2. 86dB at 1 meter (red)
3. 96dB at 1 meter (blue)
4. 102dB at 1 meter (purple)

The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.

Long Term Compression Tests
The below graphics indicate how much SPL is lost or gained in the long-term as a speaker plays at the same output level for 2 minutes, in intervals. Each graphic represents a different SPL: 86dB and 96dB both at 1 meter.
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components).
The tests are conducted in this fashion:

1. “Cold” logarithmic sine sweep (no stimulus applied beforehand)
2. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
3. Interim logarithmic sine sweep (no stimulus applied beforehand) (Red in graphic)
4. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
5. Final logarithmic sine sweep (no stimulus applied beforehand) (Blue in graphic)

The red and blue lines represent changes in the output compared to the initial “cold” test.

Parting / Random Thoughts
If you want to see the music I use for evaluating speakers subjectively, see my Spotify playlist.

• Subjective listening was mainly in the farfield at 3-4 meters in an open floorplan living room. Subjective listening was conducted at 80-95dB at these distances and occasionally higher. Higher volumes were done simply to test the output capability in case one wants to try to sit further away.
• Toy Soldiers - Resonant in the 150Hz region, her voice pops through the mix ~1kHz.
• Enjoy the Silence - Missing attack, vocals are a bit “behind” the mix; likely something in the 3kHz area.
• Higher Love - Missing that strong snare attack that I really like about this track.
• Soundstage drifts in width; i.e., “Magic” by The Cars has a mouth sound that should be on the left outside but instead is at two distinct spaces on the left; how does this match with the radiation pattern? Is the radiation uniform? Sounds varied. Looking back at the radiation pattern, this makes sense as you can see the radiation tends to shift in angle. For example, at 300Hz the radiation pattern is about 20° wider than at 500Hz before getting wider again at 800Hz to 1.3kHz and then narrowing another 20° above this and narrowing up until approximately 9kHz. This varying radiation pattern in my incredibly subjective opinion causes the soundstage to not remain consistent, meaning that if an instrument or vocal is at one place in the soundstage for the fundamental, it will be at a different location for the harmonic(s). YMMV.
• Sensitivity averages around 94dB @ 2.83v/1m.
• Obviously with an f3 of 78Hz and f10 of 53Hz, these speakers do need a subwoofer. Without the addition of a subwoofer you will find lack of fullness to tracks with low midbass (50-60Hz kickdrums, for example).
• Distortion and compression are incredibly low. In fact, the lowest I’ve measured to date, besting the $3000/pair Klipsch Heresy IV.
• No problem getting very, very loud in my large living room.
• Voices don’t sound natural; FR is quite varied and some intelligibility is lost due to the 3kHz suck out.

Support / Donate

If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute link here. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. And, truthfully speaking, help me buy lunch and maybe take my wife and kid out for dinner now and again in an effort to “apologize” for spending so much time in the garage testing all these speakers. So, if you can help chip in a few bucks, know that it is very much appreciated. Alternatively, you can use the affiliate link on my site if you want to purchase these.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.

Fantastic dynamic capability(little to no compression of either kind and low distortion).
Directivity is also pretty good. I think with a little EQ this will be a very good speaker at most any volume.

 

[johnp98]

Very happy to see more DIY speakers being reviewed!
Very excited about this one as I happen to have a pair of HTM-12 (v2 though).

Here is my in room response that I get using a moving mic method:

Would be very curious if the new version could be reviewed. Or any other DIYSG speakers. Heck any DIY speakers in general!

 

[Matias]

Where is the EQ to save the day??

 

[johnp98]

Fantastic dynamic capability(little to no compression of either kind and low distortion).
Directivity is also pretty good. I think with a little EQ this will be a very good speaker at most any volume.

Yeah the normalized polar plots seem very impressive (probably because of the waveguide), so I do wonder if EQ is the way to go to get a flat on axis response as the DI is quite good.

 

[johnp98]

Also, FYI here is what they said about the changes in the new versions
"The HTM-12 is going to be getting some changes. The new model wll be switching to a Celestion compression driver. It will also be getting a new custom designed woofer, it's based off the deltalite but has a copper shorting ring in the motor, longer voice coil, new cone, dustcap, spider and surround, and perhaps most important to some of you no more silver ring around the outside.

The new woofer was actually intended for use in a new Fusion line but since those woofers were already ordered, the stock of the 2512's was running low and the HTM-12 was going to need changes to move away from the DNA-325 anyway it was decided to put the new woofers to use in the HTM-12 as the new Fusion designs may have been a long while out. The new Hyperlite-12 woofer does loose a little sensitivity (now 95dB) but gains about 10Hz of bass extension in the same enclosure and gives more midbass kick then the original Deltalite.

With a new compression driver and woofer the crossover has also been redesigned though it retains much of the same voicing as the original. The main change being that the crossover point has been lowered to 1250hz to give better directivity matching between the woofer and waveguide and some minor response adjustments that I feel give a cleaner presentation in the midrange and treble."
Source: http://www.hificircuit.com/community/threads/htm-speaker-kits.609/page-9

 

[hardisj]

@MZKM @Maiky76 @pierre

https://www.dropbox.com/s/q7svgbf4oar04tv/DIYSG HTM-12 v1.7z?dl=0

 

[MZKM]

Too many speakers reviews at once!

Besides 700Hz & 1500Hz the directivity for both indices is pretty great. Room correction should make nice work of them.

Impedance shoots up to 100ohms!!!???

 

[aarons915]

This is basically what I expected from these. So many people talk about these and the other variations and always seem to talk about how loud they can go but does it really matter that a speaker can play at 120 db if it sounds like crap lol? I say focus on sound quality /neutrality before worrying about a speaker playing at 120 db...

 

[q3cpma]

Prime candidate for DSP, but that high port tuning (probably due to high PA woofer Fs) isn't very good, maybe even a bit too high for good sub crossover. Also, is it me, or does it lack a proper high pass filter that goes with traditional bass reflex?

 

[MZKM]

Preference Rating
SCORE: 2.4
SCORE w/ sub: 5.1

Sensitivity: 94.1dB (300Hz-3kHz ; spec: 97dB)
Frequency response: +/-8.2dB 55Hz-20kHz ; +/-6.9dB 80Hz-20kHz

 

[napilopez]

Fantastic dynamic capability(little to no compression of either kind and low distortion).
Directivity is also pretty good. I think with a little EQ this will be a very good speaker at most any volume.

Horizontal directivity is fantastic. All this needs is a little EQ and you're good to go!

Thanks for the reviews -- you're killing it @hardisj

 

[MZKM]

Horizontal directivity is fantastic. All this needs is a little EQ and you're good to go!

Cause it reminded me of it and it wasn’t in my current format, I decided to redo tthe graphs of the Klipsch RP-600M:

I know Audioholics measured them, but I wanna see a spin of the RP-8000F, as it didn’t show the 2kHz dip with as much severity.

 

[jtwrace]

Finally some proper measurements on the cult speaker.

 

[richard12511]

Preference Rating
SCORE: 2.4
SCORE w/ sub: 5.1

Sensitivity: 94.1dB (300Hz-3kHz ; spec: 97dB)
Frequency response: +/-8.2dB 55Hz-20kHz ; +/-6.9dB 80Hz-20kHz

View attachment 131590View attachment 131591View attachment 131592View attachment 131593View attachment 131594View attachment 131595​

Wow! That normalized horizontal directivity is fantastic. Should be great after EQ.

 

[muad]

Wow! That normalized horizontal directivity is fantastic. Should be great after EQ.

I'm pretty sure that is the best horizontal contour of a passive to date?

It's incredible

 

[beaRA]

Horizontal directivity is fantastic. All this needs is a little EQ and you're good to go!

Thanks for the reviews -- you're killing it @hardisj

To that end, is there an AVR/AVP that will let you apply manual PEQ to a full surround set? I suppose you could just let Audyssey/Dirac/ARC do it's thing full range on these, but I imagine PEQ based on anechoic LW would be better.