HTM Speaker Kits

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

  1. #201 SDKTheater, Jan 31, 2020
    Last edited: Jan 31, 2020
    Hey @Matt Grant,

    I purchased HT-12s for my LCR speakers and HT-8s for my surrounds. I am currently drawing up the design for the theater and figuring out the placement and angles for the speakers. Do you know the vertical and horizontal dispersion angles for both speakers (SEOS Waveguides)? I want to make sure to maximize the off-axis response as there are 8 seats in the theater. Thank you!
  2. Dispersion of the SEOS designs is approximately 90 degrees horizontal (+-45 degrees). IIRC vertical is around 30 degrees (+-15) on the HTM-12 and probably closer to 40 degrees (+-20) on the HT-8.
  3. I am going to update my Atmos 5.2.4 speaker setup for my new home and am considering these for my left and right surround speakers along with
    1099's for L C R and
    Volt 10's for Atmos height front and backs.

    How well do you think HT-10 would match up in this setup?

  4. Thanks Matt! I will take this into account and get the angle as small as possible both horizontal and vertical.

    One other question, attached is an early design of my theater. I am not an audiophile, but I do enjoy good sound. I also do not listen at really high levels. Do you think 4 VBSS would suffice? All I have experienced in my own home media room to this point is a 10" down firing sub, so the 18s would be a huge change in my mind. I am also working to see if I could incorporate the HT-12s into the front corner sub boxes (in their own enclosure) to be able to get the sound stage widened.

    Attached Files:

  5. Hey @Matt Grant

    Are the HTM models better suited for baffle wall installs vs the HT series due to the fact that they have less Baffle Step Compensation? My LCR will be either the HTM-12 or HT-12. My room is 17' 6" wide by 19' 2" long to baffle wall with roughly 16-20" behind the baffle wall and roughly 9' ceilings. It will be a single row 4 seats and MLP will be 13' away from the center speaker. I will be installing 4 large diy UM18-22 ported subs either in each corner or mid-way on the 4 walls.

    Do you have any tips for baffle wall installation? I'd be interested to hear your thoughts on these questions:

    Is it better to do a wall to wall and floor to ceiling full baffle wall with a layer configuration of 5/8" drywall-3/4" MDF-5/8" drywall with green glue in between each layer and 1-2" of acoustical foam flush with the baffle of the LCR? The wall will be angled in to house the L and R channel so they are toed in. I was going to try for a 22.5° toe in angle unless you think it should be more or less. The problem with a baffle wall is I won't be able to play with different toe in angles.

    Or do you think I'm better off having openings near the floor and ceiling corners to allow the space behind the baffle wall to act as a bass trap if I fill it with fiberglass batts from floor to ceiling? I was planning on sitting at 0.68 distance back from the baffle wall to eliminate sitting at a null and if I add openings to the baffle wall I would have to take into account the space behind the baffle wall correct?

    Should the cutouts for the speakers have a full box so to speak behind/surrounding each speaker? If so, should that box be made of the same 3 layers as the baffle wall or is 3/4" MDF or plywood sufficient? Or should it be left open? The main wall behind the baffle wall will be soundproofed.

    If a complete wall to wall and floor to ceiling baffle wall is the way to go, should I leave the cavity behind it open or still fill it with fiberglass even though it won't be used as a bass trap? I'm planning on installing batts in the stud openings of the baffle wall regardless.

    I am planning to use 8 HTM-8's or HT-8's for my 4 surrounds and 4 atmos speakers. Would they benefit from doing extra wide columns (3' or 4') angled to the MLP and doing the same drywall-MDF-drywall-acoustical foam on them to act as floor to ceiling mini baffle wall covered in AT fabric to hide them?

    Same question for the ceiling speakers if I were to build 3' or 4' squares angled to the MLP. Or is doing this a waste of time and materials?

    Sorry for all the questions, I really appreciate all the knowledge and time that you share with us here and on the AVSforum! Thanks for designing speakers for the DIY community!

  6. #206 Matt Grant, Feb 13, 2020
    Last edited: Feb 13, 2020
    The HT-10's should match up well with the 1099's and Volts, most of these designs sound more alike then different.

    I think four VBSS would be a huge jump over the single 10", I doubt you will be disappointed especially with all four subs corner loaded.
    Rew452 and ICF2018 like this.
  7. Hi Aaron,

    There is little difference between the BSC on the HT-6/HTM-6 and HT-8/HTM-8. The HT-10 and HT-12 have a little bit more BSC built in then the HTM versions but can still be installed in a baffle wall without much issue. That said the HTM-10/12 would be slightly more suited for that type of installation.

    A semi or partial baffle wall will provide the benefits to the LCR such as elimination of the boundary interference response and reinforcement of the low end, you would want it to extend at least 2-3' beyond the edges of the speakers. Filling the cavity behind with fiberglass to act as a bass trap would make good use of the space. If not doing a full wall you could probably get away with just a double layer of 3/4 MDF and 5/8" drywall with green glue.

    I'd make the boxes that hold the LCR on the baffle wall the same way. You can make them slightly oversized leaving 1-2" around the speaker, this gives you a little bit of leeway for extra play with toe angle. The gap can then be filled with acoustic foam.

    Seating should be based off the solid wall in which the bass will be contained so if building a full solid baffle wall it should be based off the baffle wall, if doing a partial baffle wall it should be based off the wall behind the baffle wall. You shouldn't need to fill the cavity behind the baffle wall with fiberglass if making it a full/complete wall.

    You don't need extra wide columns for the surrounds, make them whatever size you think looks good and fit the speaker. They only need to be 3/4" MDF construction. Again you can leave a small gap around the speaker to allow a little bit of toe ability if needed. The columns can also be turned into bass traps or absorbers by leaving the top or bottom portion of the column open and filling with fiberglass.

    I wouldn't bother trying to make baffles for the ceiling speakers though toeing them towards the MLP may be a good idea if it would be beyond about 20 degrees off the vertical axis of the speaker.
    ICF2018 likes this.
  8. Thanks Matt!

  9. HTM-12 update.

    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.
    ICF2018 likes this.
  10. #210 ICF2018, Feb 26, 2020
    Last edited: Feb 26, 2020
    Hey @Matt Grant, will there be an updated HTM-10 and HTM-8 to go along with the new slightly changed voicing of the HTM-12 for timbre matching of surrounds? Or will that not matter too much? I'm guessing the changes made to the HTM-12 are worth trading 2dB of sensitivity in your opinion?

    In regards to the baffle wall, with a full marty sub in each corner, would it be worth it to glue acoustic foam to the front face of the sub (excluding the driver and ports) and be flush with the acoustic foam on the baffle wall? Or is that a waste of foam or wrong thinking due to something else?
    Thanks in advance,


    Edit: Just saw you edited the 1st post and stated the HTM-6 through 10 is being replaced with the HT versions. Do you feel that the voicing is similar enough if I were to go with 3 HTM-12's as the LCR and 8 HT-8's as surrounds and atmos? Or would it be better to go with the HT-12's for the LCR to have complete timbre matched speakers?
  11. There is very little difference between the HT-8 and HTM-8, this is partly why the smaller HTMs have been phased out. Voicing on the HT series is also extremely similar to HTM so using there is no issue using HTM-12 LCR with HT surrounds.

    Erich knows I was hesitant on using the new woofer in the HTM-12 due to that small drop in sensitivity but I think the improvements to just about every other aspect of the HTM-12 do outweigh that small drop.

    You could certainly glue to foam onto the front of the subwoofer cabinets to eliminate the reflective surface but I'd say if their baffles take up less then 25% of the wall it's not needed.
  12. #212 ICF2018, Feb 26, 2020
    Last edited: Feb 26, 2020
    Thanks @Matt Grant ,

    Sorry for all the questions, would it be a good idea to cover the front wall (the wall behind the baffle wall) with acoustic foam or OC 703 duct board for absorption? Or is that unnecessary if I fill the front half of the space with fiberglass for absorption/bass trap?

    Would HT-10's or even all channels (surrounds and atmos) of HT-12's for complete timbre matching be extreme overkill vs HT-8's? The price per speaker isn't all that drastic.
  13. Hey @Matt Grant ,

    I'm new here and was wondering if/when the HT-8's will come into stock?? I think they would be a good surround speaker for my setup.
  14. The HT-8's will be back in stock once I get more flat packs and front baffles.

    Any general theater build questions should probably go in a different thread so we can keep this one focused on the HT speakers.
  15. Noted....sorry!
  16. #216 ICF2018, Feb 28, 2020
    Last edited: Feb 28, 2020
    I think Erich was referring to some of my questions, not yours. I was asking for details on the HT's and HTM's in baffle walls as I want to try to maximize their performance, but some of my questions didn't relate to these speakers. Sorry @Erich H.

    @Matt Grant what's the closest distance you can sit to the HT-8 and HT-12 before you can hear the lobing response due to the physical separation of the woofer and CD? I'm assuming you can sit closer to the HT-8 due to it being a smaller speaker and therefore the acoustical center is closer to both the CD and the woofer and the fact that it has a better vertical off axis response (+/-20° vs 15° of the HT-12) or am I wrong thinking this?

    The closest listener for my surrounds will be approximately 5' away vs the farthest listener will be closer to 13' away. I'm just trying to decide what surround and atmos speakers to go with. I don't watch movies extremely loud and I think the HT-8 is probably the better choice for surrounds and atmos than the HT-12 due to being shallower and having a better vertical off axis response. The HT-8's will probably even be overkill as it is coming from my current 30 year old sony 6" woofer apm-121es book shelf speakers as my L and R channels. I constantly overthink these things. Lol. If this is to close for the HT-8 to blend well then I could always go with a coaxial.

  17. Which Celestion?
  18. The HT-8 would be better for that listening distance, minimum I'd be is around 3-4' away. I'd probably want to be at least 6 feet minimum from the HT-12 if using it as a surround.
    ICF2018 likes this.
  19. Would an HTM-12 or an 88-special be a better candidate for building a large cab?

    Any differences sound quality wise which would be important to consider? I feel like I understand the differences from a usage standpoint. From the specs, the 88-special looks maybe a little better on paper from a technical standpoint? Higher sensitivity, more bass driver surface area, better matched dispersion..

    With the HTM-12 receiving updated drivers and tweaks, would this change whether a larger cab would be better or worse?

    thank you for any info
  20. #220 Erich H, Mar 19, 2020
    Last edited: Mar 19, 2020
    There wouldn't be any benefit to making the cabinet bigger for the 88-Special. You could make the HTM-12 cabinets bigger and tune them lower for more bass output. But if you always use subwoofers with a crossover set around 80hz, there isn't going to be much to gain doing that.
  21. My train of thought was running them full range and flattening response through Dirac. Possible better room response (special) by running the speakers into the lower frequencies with the subs.
  22. Neither of those speaker models are considered full range speakers. It's not good playing low bass frequencies through a speaker if they're well under the tuning frequency of the cabinets. That would be true for all ported speakers and also subwoofers.

    If you ran the 88-Special full range and then flattened it's response by boosting frequencies under the tuning of the cabinet you could damage the woofers.
  23. My previous post was assuming I would build a bigger cabinet with lower tuning, but your point of potentially damaging the speakers is well taken if using the standard cab. I guess you still run the risk of damaging even a lower tuned speaker if it’s boosted too much... This is ultimately what I’m trying to avoid. If I can have the speakers play lower along with the subs I’m hoping for better overall response thus limiting the amount of EQ needed. If using the standard cab I would cross over the subs normally using a high pass on the mains.

    I think I understand that the trade off of a larger and larger cab is less and less sensitivity? I would image as the cab gets bigger and bigger the woofer choice becomes less and less optimal. In this case I would be trying to optimize as much as possible given the drivers/crossovers are already determined. I have read a 4.0 cubic foot cab could be tuned into the 40 hz range? Does one run into woofer output issues beyond this?

    Point being, if my goal was to build a larger cab, the better choice is the HTM-12, that is really the info I was after.
  24. Oof. I was just about to buy a pair of HT-12 kits. I'm relatively new to all of this - what can you tell me about the difference between the current HT-12 and the upcoming refreshed HTM-12?
  25. Hi! Ordering the htm10. Can I add another 6 inches to the height of the kit via woodworking and to increase the depth of the speakers by 3 inches? It would become 15" w x 27" h x 12d. Would it adversely affect the sound and would it allow me to tune the speakers lower? Thanks!

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