HTM Speaker Kits

Discussion in 'Home Theater Speaker Kit Information' started by Matt Grant, Sep 30, 2016.

  1. Option A is better then option B.

    The main limitation in dispersion when placing the speaker sideways like that is the driver to driver distance. A larger distance between the drivers leads to a narrower dispersion before a cancellation at the crossover frequencies when the sound waves from the two driver are out of sync/phase as you move off to one side or the other.

    The dispersion at the high frequencies will still be more limited with the waveguide vertical (+-40 degrees instead of +-90) but that's less of an issue then having a hole in the response in the midrange, the rolloff at the top end is gradual. You will still get a hole in the response off axis with option A but you get more coverage before that happens (around +- 15 degrees) with the tighter spacing.
  2. #402 Matt Grant, Dec 1, 2021
    Last edited: Dec 10, 2021
    Crossover mod to fix the HF small dip on the HTM-12 v2.

    In my opinion the dip is so small and narrow that you aren't likely to notice a sound difference in most material unless you find content that has a note which lands directly on it and can quickly A/B. But I'm giving the option for anyone who wants to test it out.

    C3 20uF should be changed to 18uF, and a 0.22 5w resistor wired in series.

    HTM v2.1 PCB Layout (HF Fix).png
    HF Dip Fix.png
    ICF2018 and MDuyck1292 like this.
  3. I was literally soldering my XOs when you posted this yesterday. I just saw this and have ordered the new parts. I have yet to mount them so that's good.
    How do I solder the two loose ends together?

    Attached Files:

  4. Do I hot glue the resister to the capaciter?
  5. Matt,
    Is there some way you can post actual images of the update instead of diagram - for the people who are solder challenged or others who ordered assembled crossovers and will need to solder for the first time (guilty).

    Thank you sir
  6. I don't have an assembled crossover to use for photos example but here is the example on a bare board with those two parts.

    Obviously you would add a bit of solder where I have the two leads twisted together. The 5w resistor can be glued down right there next to the capacitor and the other two leads get soldered on the bottom like normal.
  7. That's great news, congrats.
  8. Is it possible to over stuff or pad the inside of the htm12s? Initially, I used one layer of mattress pad plus polyfill around the CD area. I just added a second layer of mattress pad and noticed some of the brightness of the speaker is gone (I actually prefer a little bite in my highs). Is it due to the added layer of mattress that affected the sound OR is it a case of phantom hearing I am experiencing?
  9. The crossover is well below the treble range and stuffing/damping inside the cabinet only affects the woofer. So I suspect that might just be phantom hearing. Though if it somehow altered the overall tonal balance resulting in more midrange/bass that could have the same effect as lowering the highs but usually the bass in ported cabinets is reduced as you add more damping material.

    No way to really know for sure without taking a before/after measurement.
  10. #410 David Andre, Dec 10, 2021
    Last edited: Dec 10, 2021
    I would love to see this and the HT10 back in play. I need an LCR solution. Also would be nice to have a high SPL (horizontal) center channel options for those of us that can't just use a 3rd HT10 in the middle.
  11. Watch a soldering video. Use a stick type soldering iron (35W Weller?) for ease of use. You will find it pretty simple, don't be intimidated!
  12. What speaker insulation is everyone using now that UltraTouch is discontinued?
  13. I'd use a combination of lining the walls with 1.5 to 2" acoustic foam and polyfil, adding the polyfil in the top portion of the cabinet.
  14. Is this sufficient 'stuffing' for the HT-8?


    Acoustic foam is 1 3/8" thick measured from the flat back to the tip of the 'peaks'.

    If I leave 2 1/2" from the corner bare, will that provide enough room for the ports to 'breathe'?

    Related question; when cutting the ports to the 2" length, that is measured from the outside front of the port back to the cut location? (vs. from the back of the flange)

  15. That should be good, it certainly looks like you have enough room in the corners as well.

    The ports are measured as overall length, so the outside of the front flare/flange to the cut point.
  16. I messed up when assembling the crossover for an HT-8. Is it ok that this coil is horizontal rather than vertical?

  17. It's not ideal but shouldn't be a huge issue.
  18. Thanks for the quick reply!

    Do you think it’d be worthwhile to fix? It’s a stupid mistake, and definitely don’t want the SQ affected.
  19. If you used hot glue, it shouldn't be too hard to cut the zip ties then use a heat gun (or perhaps hair drier of you don't have a heat gun) to melt the glue and flip the inductor upright. You can even cut the smaller ties on the inductor itself to give yourself enough length on the leads so that you don't need to unsolder.
  20. Is this padding too much? Is it okay to cover crossover with foam?

    Attached Files:

  21. BTW it’s HTM 12.
  22. Should be ok, watch where the ports go you don't want them to run into the foam. It should be ok to cover the crossover but it really doesn't hurt anything leaving it exposed either.

    Top portion by the compression driver/waveguide can be filled with polyfil for a little extra damping.
  23. Thanks Matt. I think ports have couple off inches from their back to foam. Do I need poly fill behind CD in addition to foam?
  24. You shouldn't "need" polyfil there, it's just a good place to add it for a little extra help at reducing internal reflections.
  25. Thank you Matt.

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