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DIYSG HTM-12v1 Speaker Review

Joecarrow

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I took the internal dimensions of the HTM-12 and plugging them into a room mode calculator: amroc - THE Room Mode Calculator (amcoustics.com)

It's obviously not the way the calculator was intended to be used, but you can click "do it anyway" and see low order modes from 285hz up past 800hz. Some of the modes stack up since the internal dimensions are pretty close to a 1:2:3 ratio. It might lead to extra scrap MDF from a sheet, but if the dimensions were altered just a bit then perhaps the resonances would have less impact without us having to heavily stuff the box.

If there are any resonances much below 285hz then it seems like they would be wall flex related and would have to be addressed with bracing.
 

Ericglo

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Greetings gents. I've stumbled onto the website and this thread. As a fairly early adopter of the HTM-12 ver 1 (Jan 2017), the tests and all your comments are very interesting. I am not a speaker designer or even an engineer, but have just enough training and experience to enhance my listening enjoyment. With much time spent in very fine screening rooms and such in my career, I have a subjective bias for the experience that speakers in large rooms renders. These tended to be dubbing stage in size and quality. For this reason, I find the characterization of this type of speaker as "Power Hi-fi" a good one. My room is large, and throw distance to MLP is about 15'.

Back in the day when I built these, I did a close mic look at the HTM-12v1 well away from boundaries using OmniMic, and found it reasonably smooth...more along the lines of what Matt provided at that time. Based on that, it is likely my HTM-12 components came from the early runs that Matt used. It would be far from a definitive look as provided here, but it was good enough to get some idea about what to expect, and significantly different from other well designed manufactured models I've done the same with.

Based on the availability of the results here, I have a question for the gallery regarding the ongoing discussion here of speaker EQ and room correction EQ. Given that we have test results showing not only axial response, but also sound power, it seems that the HTM-12v1 has similar horizontal on-axis and off-axis performance which would appear to lead to a power response that is similar in shape to axial response (just at a lower level). Would this not indicate that a room correction platform that is based on a mix of axial response and power response will also improve axial response, improving the room and axial response at the same time? Although the discussion here is specifically about the HTM-12v1, is the concept the same for others?


Good to see you here.

I think @mitchco would give the best response to your question.
 

johnp98

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My idea was that I could design the active network to get the crossover as good as it could be, then build it from passive parts (assuming it wasn't costly/complex).
That said, I might (might) try to toy around with some DSP things on the miniDSP with this speaker and see if I can come up with an active design that is pretty cool.
That would be quite amazing! I think you could team up with any speaker designer (or even do it solo) and could make a killer active speaker with your klippel measurements and setup.
The question is what base speaker you would want to start from. If you did it with the HTM-12 v2 that would be amazing as that happens to be the speaker that I have, but I do think that you could make a killer active speaker that you could sell and generate income with.
 

johnp98

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Looks much, much better. And sounds that way, too. If you (we?) could figure out what is causing those resonances then you could clean up the midrange and really make this sucker shine.
Yeah if you could collaborate with DIYSG or Dr. Earl Geddes and design a speaker with a waveguide and then +/- active vs passive crossover you could have a killer speaker on your hands that I am sure would sell like hotcakes.
 

jtwrace

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Yeah if you could collaborate with DIYSG or Dr. Earl Geddes and design a speaker with a waveguide and then +/- active vs passive crossover you could have a killer speaker on your hands that I am sure would sell like hotcakes.
Pretty sure he doesn't really want to do that. Yet.

**until...
 

johnp98

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Pretty sure he doesn't really want to do that. Yet.
I could see how that could open a can of worms with dealing with inventory and stock and shipping etc. So teaming up with someone who is willing to do all of that probably makes the most sense, but I do think that the Klippel is an invaluable resource and so I am just tossing out ideas that would presumably be lucrative if the proper arrangements were made and the proper cut went to all parties involved.

But I also won't complain if we keep getting amazing reviews, as that is invaluable and will work its way back to speaker designers and improve the accountability and designs of countless speakers.
 

jtwrace

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I could see how that could open a can of worms with dealing with inventory and stock and shipping etc. So teaming up with someone who is willing to do all of that probably makes the most sense, but I do think that the Klippel is an invaluable resource and so I am just tossing out ideas that would presumably be lucrative if the proper arrangements were made and the proper cut went to all parties involved.

But I also won't complain if we keep getting amazing reviews, as that is invaluable and will work its way back to speaker designers and improve the accountability and designs of countless speakers.
Since you're new to the site, this might interest you about Erin. ;)
 

johnp98

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Since you're new to the site, this might interest you about Erin. ;)
Yeah I have really gotten into audio stuff ever since covid and have watched lots of videos and been reading tons. Have made it through Dr Tools book and more including all of your audio videos (and am a subscriber).

Don't know how you get all these high end people but I certianly have enjoyed them! The Geddes one was especially good. I assume Dr Floyd Toole is on your wish list, as that would be amazing.
 

Scgorg

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Yeah I have really gotten into audio stuff ever since covid and have watched lots of videos and been reading tons. Have made it through Dr Tools book and more including all of your audio videos (and am a subscriber).

Don't know how you get all these high end people but I certianly have enjoyed them! The Geddes one was especially good. I assume Dr Floyd Toole is on your wish list, as that would be amazing.
I might be misunderstanding you, but Floyd Toole has already had a chat with Erin on his youtube channel! It was a great episode, well worth the listen.
 

johnp98

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I might be misunderstanding you, but Floyd Toole has already had a chat with Erin on his youtube channel! It was a great episode, well worth the listen.
Yeah there are not many videos of Floyd Toole and so I know of his recent chat with Erin and his older CIRMMT talk.
I was talking about The Intellectual People Podcast and hoping that he would be able to interview him at some time, as any and all interviews with him do seem quite fruitful.
 
OP
hardisj

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I was going to PM Matt but since we've been sharing stuff out in the open I thought it might make sense to just go here, too...


Hey, @mtg90. I got the crossovers yesterday and installed in one speaker. I think there was a miscommunication somewhere in the line; I thought you were sending another woofer/CD for me to retrofit the additional v1. So, right now, I just have one retrofitted v1. But, honestly, with the additional expense of shipping and whatnot... I'm OK if you don't want to send the additional woofer and CD. I can test the one v2 speaker, do some listening in mono and we can rely on the test data to tell the rest of the story.

Just let me know what you think and we'll go from there.

Oh, and I wanted to thank you for the donation! I appreciate that. I'm using some of it to purchase a window mount AC and/or de-humidifier so I can keep my garage more regulated (it is insulated by my kiddo likes to raise the garage to play outside during the day with the neighborhood kids and it gets hot in there quick and the insulation traps the heat in when I close it at night). It takes a while for me to get it cooled back down so I am just going to get an AC for my garage side. The donation is definitely going to be helpful to cover those/that expenses.
 

ooheadsoo

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I hope whatever miscommunication gets sorted out soon. Looking forward to refining my DSP settings on the HTM-12 v2. Both v1 and v2 should be excellent deals in combo with EQ/DSP, if you want a dynamic system that never sounds strained. As HT designs, DSP usage and subwoofers are essentially givens. I am still glad to have been able to have a taste of the GedLee speakers without the same costs.
 

jtwrace

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I hope whatever miscommunication gets sorted out soon. Looking forward to refining my DSP settings on the HTM-12 v2. Both v1 and v2 should be excellent deals in combo with EQ/DSP, if you want a dynamic system that never sounds strained. As HT designs, DSP usage and subwoofers are essentially givens. I am still glad to have been able to have a taste of the GedLee speakers without the same costs.
They're not even close to GedLee speakers.
 

jtwrace

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I have little doubt you are right but were his speakers ever independently measured ?
Yes, and I really hope you're kidding.
 

ooheadsoo

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I think a quick Google will turn it up. I think Princeton? used the Nathans for a study of theirs.

Geddes used more expensive drivers for sure, but I recall the straight OS shape to have its own minor issues. The polars aren't obviously better to me. The point is that this is heavily inspired by Geddes' work, and that they nailed the directivity. Geddes also went active with minidsp in some iterations.
 
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