Pete Fowler

Last update - LASE was out of stock (web store wasn't current). I have not found new/NOS K53 diaphragms anywhere. Fortunately one of the forum folk has parted with a used pair so I'm good to go. Cheers, Pete

Actually two things change when you swap in a K-28 (both good in my view)... As you guys mention the woofer will be 3dB louder (this helps compensate for the squawker-forward voicing of the stock Heresy's which is a good thing in my book), plus when you halve the speaker impedance from 8 to 4 ohms it effectively doubles the woofer's crossover freq from around 380Hz (in H2's with the later version xover) to 760Hz which would help fill the gap in the K53's low end that I mentioned before. Two - two tweaks in one! 🙂 That said there is more benefit using a K-42 or the Dayton than just power handling - they both have very strong magnets (much stronger than the K-28) which improves the motor control over the cone at high(er) freqs - which leads to better integration with the squawker. If you read Claude's thread on the Super Heresy's a few years back the primary reason he tried the swap was to improve the integration, not improve the bass. Thus a K-42 swap improves integration (speed and dynamics) plus bass to a greater degree than the K-28, but I think the K-28 would be huge bang for the buck if you're inclined. Just sayin'... Cheers, Pete

Interesting - I had the same experience while looking for a replacement diaphragm for my K-53. Automated first response, automated 'please be patient' email, then nothing. Perhaps they're backlogged and we'll hear in a few weeks?

Good point Randy - I guess it all depends on what a person is trying to accomplish. I was trying to duplicate the results Claude achieved with the K-42. Reviews made me think the K-28 still leaves the speaker overall bass-light (even ported in the H4). It also doesn't blend significantly better with the squawker (speed-wise). Big magnet drivers like the K-42 or the Dayton are a better match for the squawker dynamics although in the case of the Dayton some xover work is needed as mentioned above. When ported they also put out serious clean bass (which occasionally makes me giggle 🙂). As a drop-in upgrade the K-28 is much better and will give reliable results (although I think the H4 has some xover changes?). Either way it's a hoot to hear the results so a win-win no matter which approach.. Thanks, Pete

Hi Jd, Yes, dropped the cap and shrunk the inductor because despite the name the K53's '700' horn doesn't go anywhere near 700Hz. It's more like an 850Hz horn. So I ended up with a 1.2mH inductor crossing at 925Hz which blends really well with the K53K. I also had to add a zobel network for the woofer because the big voice coil has a ton of inductance and the rising impedance messed with the xover response. I was getting bleed through into the 4kHz range without it. Pretty interesting stuff once I figured out what was going on. 🙂 The final tweak was to extend the port length to 6" which is a nice compromise between extended low bass and a slight loss of detail in the 80-120Hz range. To my ears an acoustic bass sounds still sounds tight and right but you can really hear/feel the bottom end now. All in all a worthwhile upgrade. Cheers, Pete

A quick update as promised - I ordered from zxpc (LASE) on Dec. 17th - and...nuttin'. The order is still 'Processing'. Tried two emails and a phone call - no response. Since they're a small company I'm thinking the covid spike may have impacted them. I will give them another week... PeteF

Found one - thanks!

I've ordered two units from LASE - will update this thread once they arrive. I'm curious to compare my original set to these since the site doesn't claim they are OEM or Klipsch parts. Fortunately I still have one working original to use as a baseline. On a different topic - I've ported my H2's and replaced the K24's with Dayton PA310-8's (inspired by this thread - ) Would it be interesting to share the xover mods, etc. I needed to make those woofers work in the H2's? Thanks again to all! Pete

Thanks all - I had already checked Crites Speakers, etc. and no luck. However the link Randy provided has 2 available - I'll try my luck there. This community is the BEST! Pete

Thanks Randy - I just assumed they no longer made replacement parts for 35 year old speaks. D'oh! Request submitted...🙂 Best, PeteF

Thanks Madman - I'm hoping to find a replacement diaphragm but will keep these in mind! Pete

Hi All - I recently noticed the squawker in one of my H2's was down in output below 2kHz - turns out the voice coil DCR is up to 28ohms. It still plays but it's down 7-8dB. I can't find any source for a replacement. Any suggestions? Many thanks, Pete

One of my Heresy II squawkers dropped in output and when I measured the VC it was 28ohms. 😬 Still plays but down 7-8dB. Hoping to find a used replacement since all the new parts vendors are out of stock. I'll take one but if you have a pair I'm definitely interested (if they came from a pair of speakers with similar use/age/etc for better match). Many thanks! Pete

Been lurking for a while and I hope I can add something back to the community - I've recently installed/ported the Dayton PA310-8 in Heresys. The snag is I have Heresy 2's. Searching for more bottom end I replaced the K24's with Crites woofers and that made some improvement in bass but not enough (for my tastes/room). Recently swapped in PA310's and followed Claude's guidance on porting, etc. As predicted the mid/lower bass is both extended and more forceful while avoiding one-note/thumpy effects - it's clean and fast. The mids (esp. female vocals) are much better, too. The overall sound is good top to bottom. Well worth the effort for H2's. This is a pure guess but I think it may work the same in the H1's since you like their sound without porting. YMMV, etc. One caveat for stock H2's - the 2.5mH/68uf low pass filter sounds a bit thin in the lower male vocal range (for my tastes 😉) so I 'm thinking of trying a smaller cap to raise the freq up from 386Hz to maybe 430-450Hz. I'm holding off until the drivers run-in a bit more before I make the final call since it might open up the upper bass as the suspension loosens up. You probably won't have this issue with the H1 xover but just in case... Pete

Howdy, Sorry the table is hard to read - the forum SW compresses spaces...with the ports cut to 7" and the sides braced: -1 at 120 on up +3 at 50/60/80/100Hz +0 at 40Hz +6 at 31Hz +2 at 25Hz/20Hz Thermio only ran up to 200Hz because we use these cabs as bass bins below 180-160Hz with Oris horns. Can't answer your 300-150 hump question. The cabinet is on a side wall about 1.5 ft out from the wall, sitting on spikes with carpet over concrete. We used a CDP with a test tone CD and a RadioShack digital SPL meter. No room compensation, etc. included. Frode posted pics of his project in the thread below "...pictures anyone?". Ours look essentially identical. Now, all the data and facts aside - its sounds really good which is the real point of the mod, ya? Acoustic jazz, rock, vocals - you name it. Thermio is a really particular guy when it comes to clean, articulate bass... You might try building a pair - they're simple boxes and the K33E drivers are around $105 ea. Can't beat it...

Hey D-Dee, Yes, you must add length to the port to compensate for the flares. The rule of thumb I seem to recall is 1" per flare, so a 6" port flared at both ends should be 8" total - flare to flare. I think this is documented on the Precision Port website... Hope this helps!

Hey Ken, I can't help you with a full LaScala - I'm only using the bass horn portion with my Oris 150 horns. That said, this mod seems to lose some energy in the upper bass (250 to 120Hz range), so you'll want to boost that by 2-4dB (or cut the mid-horn and tweeter 2-4dB). I don't know if the LS crossovers have L-pads or something else that will allow you to do this. Others on this forum should be able to help. You'll find the music loses impact if you don't adjust for this loss. Shortening the port length to 7" really helps restore the mid-bass speed and slam, too. The EQ that djk mentions is designed to boost the lower bass up to the level of mid/upper bass output of the horn. I believe the LS is only horn-loaded to around 100Hz. You can still perform this mod without adding low-end EQ and have a respectable boost in mid-lower bass energy. But if you're a low bass freak it won't be enough. :-) Here are a couple other things Thermio and I ran across while experimenting... 1. The LS bass cabinet was designed so that the side walls can vibrate and add energy to the "perceived" mid-bass. If you expand the woofer chamber and port it, you no longer need the sidewall "enhancement". In fact, it muddies up the sound something terrible, well into the midrange! I see you want to keep the mods reversible, but I highly recommend bracing the sidewalls (as Frode has done - see his pics) to clean up the sound. As an experiment, I did the sidewall bracing first and the improvement in the mids is definitely due to suppressing the cabinet resonance. However, the midbass drops off a lot so you'll need the expansion/porting mod to bring it back. I'm trying to give you the big picture so you can make intelligent tradeoffs. Porting + side braces = great, but one without the other is not good in my opinion. 2. Put the LS on spikes - I thought Thermio was nuts to suggest it since the speakers are so heavy to begin with, but on carpet it makes a big difference. I've never tried it on hardwood or tile flooring. Hope this helps!

Hey Randy, The port I'm referring to is the 4" Precision Port, part number 268-352. I've seen the Parts Express sourced port and you're right, its not flared. The precision port does have flares at both ends and its a bit more expensive. I'm not sure I buy their claim of 3dB increased efficiency, but every little bit helps, ya?

My buddy Thermio and I both scratch built a set of LS bass cabs and he did the djk mod to them. He took measurements on one cabinet as the mods progressed. Here is the data: 200 160 125 100 80 63 50 40 31 25 20 HZ 77 80 79 73 72 78 68 60 61 52 51 dB Stock, mouth braced 76 78 78 73 69 75 65 60 66 56 52 4.5 cuft, no ports 76 78 77 75 74 80 70 60 68 54 54 Two 4"dia 10" ports 76 79 78 76 75 80 71 60 68 54 53 Ports cut to 7" The interesting thing with 10" ports is the boxes went deep, but the snappy, fast horn sound was lost! Cutting the port length to 7" brought the snap and speed back to same as stock, plus the lows remained, esp. at the 31Hz box tuning point. This data is with K33E driver and light stuffing. We think a K43E in this box would be superb, but haven't tried it yet. I'm going to try the mods using two 4" ports with both ends flaired (Thermio used 4" PVC). Flaring is supposed to reduce distortion and possibly increase the gain. Parts Express sells the kits. Neither of us is going back to stock. Pete