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Opinions on KLH Model 5

I have the same (minor) questions about whether the mids need it, but if the factory did it that is enough for me. Additionally, since the Fives have two mids I don't know that it's going to cause a suck-out of the mid frequencies with a light coating or if it would actually enhance them either. There's enough threads where I'm hearing others doping the mids to no reported detriment that I would do it too.

It'd be nice if someone could post the official KLH bulletin on the matter regarding the mids. That would firmly close the discussion.
 
The bulletin would only confirm KLH's recommendation...not their rationale.

I have trouble understanding how it will improve performance, but can see how it might have the opposite effect.

Perhaps, as suggested above, it is intended only to reduce deterioration, rather than improve performance.
 
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spark1 said:
The bulletin would only confirm KLH's recommendation...not their rationale.
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That's what I'm looking for - KLH to tell us it's needed.

That will eliminate the questions about whether it should be done. I care less about the why, but that would be interesting to know. KLH didn't put their rationale into Bulletin #60 so if there is another similar bulletin I wouldn't expect the science to be included.
 
spark1 said:
The bulletin would only confirm KLH's recommendation...not their rationale.

I have trouble understanding how it will improve performance, but can see how it might have the opposite effect.

Perhaps, as suggested above, it is intended only to reduce deterioration, rather than improve performance.
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I'd like to know the rationale too. I do know that dried out KLH surrounds seem pretty floppy, if not fragile. Coating them with the correct goo helps that, at least.
 
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I found that doping the surrounds on my Sixes had a noticeable impact on the bass and midrange response. The midbass hump around 100Hz was tamed, low-bass response was slightly extended, and there was less "breakup" around the crossover point. THD was also noticeably reduced, especially in the bass region. Sounds a lot smoother now, although some may prefer the mid-bass hump.
KLH 6.png

https://audiokarma.org/forums/index.php?threads/klh-model-six-restoration-underway.876472/ You can find more discussion of this, and also graphs measuring the change in distortion, here.
 
Interesting.There definitely is one theoretical advantage to not doping the mids: driver protection in case the midrange box seal failed and you happened to be playing something with a lot of bass at high volume. BUT, if that's what Mr. Kloss originally wanted, then that's what I will do.

I don't think this box will fail when I'm done with it. All the original putty used to help make a seal has become useless, so I replaced it with gorilla wood glue. Pretty sure there's nothing to worry over.
 
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spark1 said:
Makes no sense to me.
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The two KLH Five mids have cloth surrounds and open backs and are installed in their own separate acoustic chamber which is sealed and isolated from the much larger woofer chamber. The frequencies may not be as low; and the chamber may not be as large; but the mids are operating on a similar principal, and they only work properly if they have the proper level of "airtight-ness".
 
After listening to just the mids when I put them back in (testing the crossover), they produce a very clear, full, and detailed midrange that is easy on the ear. When you listen to them along with the tweeter, something magical happens, and everything sort-of becomes more 3-D....tough to explain, but these really are excellent drivers. I'll be done with these in the next few days, and I'll post some pictures.
 
Finished it all, and I have pictures to upload. This last week, I've had the fun of A/B/Cing these with my OLA and Soundcraftsmen Lancers (2640TX drivers). Both the OLA's and KLH 5's pretty much stomp the Soundcraftsmen speakers (as much as I hate to say it) when it comes to imaging and presenting a believable soundstage. Between the Advents and KLH speakers, I really cannot pick a winner, as both reproduce sound much to my liking. Both the Advents and KLH provide an acceptably flat frequency response according to the SLM I was using, and the main differences appear to be in the midrange(call me captain obvious):

- OLA seem to project singing/talking voices, acoustic guitars, and other instruments that dominate MF just behind the speakers. Like you're a few rows back in a small concert venue.
- KLH 5 project all of the above right in front of the speakers, as if you're in the first row, right next to the musicians.
- Relative to the above, the Soundcraftsmen Lancers drive midrange into your ears, like if Miles Davis had his trumpet up to your head. West Coast sound on steroids.

These are re-capped Advents, using much better film capacitors for the HF drivers, so the shrillness is gone. If that wasn't the case, I'd say the KLHs have a smoother high-end, but at the moment it is a tie.
Bass is also a tie, both can shake the walls in my apartment all the way down to about 28Hz.

I love both, and they do a great job into fooling me into thinking I'm right there when I close my eyes. That is what really matters to me, and Kloss speakers do it quite well IMO. All listening was done with on-axis speaker positioning, elevated off the floor with make-shift speaker stands about 10" high, using an NAD 3120.

I will be listening to these newly acquired KLH speakers for a long, long time.
 
Interesting that you feel the OLA's and KLH Fives are in the same league. I've got both, but haven't restored the Fives yet. The cabinets are similar and the size and weight are similar. The Fives are 3-way and the OLA's are 2-way.

I wasn't impressed with the OLA's, but I had PeteB's offer of a BSC circuit that would improve them significantly. (I guess that it is a filter network that changes the frequency equalization that you insert in the pre-amp circuit or tape loop.) I have never built or tried the BSC circuit, but without it I just was underwhelmed in comparison with my KLH Sixes. (I know, very subjective, but that was my impression from listening to both the OLA's and KLH Sixes.)

I'm not expecting the KLH Five to be a step down from the KLH Sixes I have. Someday I'll answer my own question when I dig down that far in the queue to restore the KLH Fives.
 
Hey Tim

At least to me, they're in the same league. You should definitely restore those fives, I think you will like what you hear. Instead of a BSC circuit, I would recommend an equalizer, sound level meter, and a pink noise generator(or a test LP with pink noise). This is pretty accurate way to get the most out of your speakers. I've had great results with the Advents, but for this test, I left everything unaltered.

I like the KLH Sixes as well - they have a beautiful, smooth sound. I'd say the OLA & KLH 5 are both a step or two up from the 6 in regards to deep bass reproduction, and the KLH 23 might be another step up from that (same woofer as the 5, but more cabinet volume, since there's no midrange box taking up a bunch of space).
 
Robbie_uC said:
and the KLH 23 might be another step up from that (same woofer as the 5, but more cabinet volume, since there's no midrange box taking up a bunch of space).
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Robbie, right you are. I have both 5's and 23's, restored. I measure the 5's box at 1.51 cu/ft and that's with subtracting the mid enclosure. The 23's measure at 1.72 cu/ft. I have NOT done an A/B test on them, yet.

I have 2 pair of OLA's. Walnut and utility. I built Pete's BSC box. It works good but I haven't done any serious listening with it in/out.
I plan to econowave the utility OLA's and put teak veneer on them. I have the teak and e-wave parts, now its a time issue.

Tim D......I can loan you my BSC if interested. I'm sure Pete's offer is still good. I'd love to hear how your 6's compare to your 5's once restored!

I'd love for Pete to econowave some OLA's and run tests comparing his BSC to e-waved OLA's.

I retired on 12/15/18 so after I get caught up on a few projects I will do some serious speaker comparisons.
 
Too bad everyone is so far away from me. I would love to hear opinions on my rebuilt 6s with modern cones and surrounds.

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GD70 said:
Did you post a video of these in the video thread? If not, pease do so we can get an idea of how they sound. If you did, please copy and paste the link so we go directly to your post.
Cheers, Glenn
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Not yet....I will get that done this week.
 
Robbie_uC said:
That's awesome! I'd love to hear that! Kinda looks like an OLA replacement cone....If so, it is interesting to know that the Voice Coil and & Former are the right diameter.
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It is indeed an Advent cone and foam. The KLH stuff is no longer available. Neal's speaker service did the work for me and he had to us a 3d printer for one of the parts (dont know which one).
 
OK a quick test on uploading videos. I dont have the KLHs up right now but I will try tonight to get them in. This is showing my Optimus 5s/Sansui G 5700 combo in one of the bedroom systems. When I pulled back the bass was making me shake the phone a bit, but hard to tell in the video. Oh and my side of the bedroom is a bit messy!

 
Hey, Optimus 5's! Never heard those in person, unfortunately. Nice setup, looks like that's quite enough to keep you busy tinkering and adjusting
 
Robbie_uC said:
Hey, Optimus 5's! Never heard those in person, unfortunately. Nice setup, looks like that's quite enough to keep you busy tinkering and adjusting
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They are a great sounding speaker. Whenever I rotate them out I miss them. Our spare bedroom is filled with other speakers including the KLH 6s. The Optimus 5s, Imperial 6s and KLH 6s are my favorite three speakers I own.

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