HTM Speaker Kits

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

  1. I wouldn't change the internal volume or the tuning on the HT kits. They blend very well with a subwoofer when built to the original dimensions. You could build them slightly bigger and tune them a little lower, but they would still need to be used with a subwoofer, so there isn't much to gain.
  2. #227 Matt Grant, Apr 6, 2020
    Last edited: Apr 14, 2020
    The HTM-12 is a more premium option to the HT-12, it uses higher quality drivers and more advanced crossover design to give the speaker a smoother response and better sound quality. The biggest on paper difference is that the new HTM-12 woofer trades a little sensitivity for more midbass output and more bass extension.
    Edit - it also has double the xmax of the woofer in the HT-12 giving it greater output capability in the bass range and higher power handling.
  3. Any updates on when the HT-8's will be in stock?
  4. Waiting for compression drivers on the HT-8's. They were ordered about 4 months ago but I think all manufacturers have slowed down right now. Hopefully they get here soon.
    Nick S likes this.
  5. Erich, is the HTM-12 kit currently shipping with the new hyperlite woofer and celestion CD?

    I was also curious if the crossover is still all air-core inductors. I try to stay away from iron-core inductors.

  6. Yes, it's the new kit with the new Hyperlite woofer. The kit uses iron core and air core inductors. Not sure why you wouldn't want to use iron cores.
  7. Thanks Erich!

    Good news! I did a bit of further research, and it seems that iron-core distortion components are likely more benign than the distortion components coming out of the speaker driver it is pushing. At least in the frequency domain. Although, it is interesting that the air-cores do measure much better.

    If you are wondering where my concern came from, I was reading a Q:A of the engineeeing team behind the new Purifi Audio company. Their prototype amplifier is already putting out industry leading measurements (posted at AudioScienceReview). So their opinion is valuable to me.

    . . . .back on topic, in the Q:A the team goes on to explain

    "The only real surprise we had recently was to do with the output choke. Magnetic materials have something called hysteresis, but there is precious little information about what this really does. If you test a magnetic core with a sinewave the distortion looks a little like soft clipping, perfectly benign. But what came out of tests on iron parts in loudspeakers was that hysteresis has a long term memory so you can get intermodulation between things that happen now and things that happened 10 minutes ago. With music this distortion sounds like half correlated noise. . . .

    . . . .We have a strong suspicion here that the most audible distortion in typical class D amplifiers may very well be that. . .

    It's a fun read! (Sorry, couldn't post any links because I get a spam error)
  8. You can use those other inductors if you want but I don't think you'll notice much difference. I've seen some guys build the HTM's with those 'boutique' capacitors that cost $80 each and Mills resistors, etc. Definitely nothing wrong with doing that if you feel it's worth doing.

    Keep in mind that some of the best sounding speakers out there, and kits that have won the most awards at audio shows (like Jeff Bagby's Continuum) use iron core inductors. Pretty sure they are commonly used on the woofer legs of the crossover. I think Bill Waslo told me they had a benefit over air core when used on the woofers.
  9. I decided to go with I-core inductors in the updated HTM-12 because the lower DCR gave the response shape I wanted and was more efficient then using the air cores in the previous version. You could swap the included I-core inductors for air cores of the same value though you will need 14-15 gauge inductors to keep the DCR low enough.

    Due to the high sensitivity of the design and the low crossover point (for a two way) both saturation distortion and hysteresis from the I-core inductor are kept at much lower levels then they would be in a more conventional speaker design using similar inductors at the same playback levels.
  10. Thanks Erich and Matt!

    Erich, I totally agree! Speaker engineering is the ultimate balance of pros vs. cons. I hope my post didn't come off as rude :)

    Matt, thanks for telling me that the value is small enough to replace with an air-core! I was actually wondering this, but I didnt want to bother you lol.

    Are there any plans to post an update or information about the development of the new Hyperlite woofer in the HTM-12? I'm really looking forward to the story/measurements.

    Im excited about the celestion CD driver too! I scanned the internet for FR/THD graphs of Compression Drivers, and couldn't find a smoother FR with a proper frequency response tilt.

    I'm fully expecting this kit to be a "giant killer" that will write it's place in history. Cheers!
  11. Just ordered a pair of the HTM-10s. I'll be eagerly waiting for news of the HTM-8s being back in stock!
  12. You mean HT-10's. HTM-10's were retired last year.

    I spoke with Celestion last week and the stuff for the HT-8's should be here very soon.
  13. Ooops! Yeah, I meant the HT-10 :)

    That's great news on the parts. Looking forward to my first builds :)
    Uneventful_Event likes this.
  14. Cant wait to see your build/hear your impressions brother!

    Have fun :D!
  15. Where is the off-axis graphs for the HT series go?
    I can not seem to find them.
  16. One out of two packages delivered today! I wonder what the story is on how they got split up lol.

    I was excited and took unboxing photos :)
  17. Package 2/2 delivered today! It was pretty soaked but everything inside was bone dry thankfully.

    Glued up my first enclosure today. Used four strap clamps along with Titebond 3, and it worked GREAT! Build log day 2 here:
  18. I always wondered if those type of clamps would work for box building. I might have to give them a try.
    Grats on getting started and for the pics as well.
    Keep us updated!
  19. Marc, I have a couple of those exact strap clamps and I can't get sufficient clamping pressure out of them in the direction I want it to go.

    Laying the speaker box on a bed of pipe clamps is a good start because they're really cheap for what you get and they just work so well at this exact use. They also just do not deflect, and if you keep a number of different size threaded pipe around you can mix things up. All metal f-clamps generally don't disappoint, even the Harbor Freight ones, just pay attention to depth of the bar. If you really want to spend money then Revo parallel clamps are just monsters and will give you all the squeeze-out you can ask for.

    In my opinion the biggest issue with the strap clamps is that they have limited uses whereas all the others I mentioned can be used in a wider variety of ways. The strap is handy for getting pressure on quickly and it can be unobtrusive for when you want to get other clamps on the workpiece.

    The best thing no matter what you've got is to first do a dry fit and come up with your clamping strategy while you're not rushed for time. Glue-up rhymes with screw-up and when things are getting tacky and oozing out is a bad time to realize that you need to change things up to get job done with what you've got on hand.
  20. #245 Mandroid, May 29, 2020
    Last edited: May 30, 2020
    For those not using the HTM-12 flat packs, would it be beneficial to change the depth of cabinet or tuning for the new custom Eminence woofer vs the cabinet for the original Deltalite?
  21. Curious to hear if there's an updated ETA on HT-8 availability? :)
  22. If your are not using the flat packs you could make the cabinet tall/deeper in the 2.5-4cuft range tuned to 40-45hz if you want even more bass extension from the design. That said if you are going to cross over to subs at 80hz it won't provide much benefit over the standard flatpack design. The trouble with a larger cabinet is that it will be difficult to achieve the correct tuning in a larger enclosure with the stock baffle and ports.
  23. Hi Matt, any baffle step/voicing concerns if I place the HTM-12 on stands approximately 2 feet from the front wall? Thanks!
  24. No, when these were designed I tried to voice them in such a way that makes then suitable for both baffle wall or freestanding/stand mount placement. Most of the major voicing was done stand mounted since I figured a majority would use them like that rather then in a baffle wall.
  25. Hi everyone I recieved my ht10s awhile ago now it's time to assemble the crossover. I just wonder if there any crossover schematic posted anywhere? Help would be appreciated.

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