Ohm Walsh F Hope of Resurrection

Douglas, the putty on the inner surface of the titanium section of the Ohm F cone will dry out over time. It is a known issue for older F's. The speakers will play but the treble sound from that part of the cone can be different. As an engineer, this makes perfect sense to me, as follows.

The putty acts like a dampening material for the wave travelling through the upper segment of the cone. To dampen the wave, it has to have just the right 'flexibility'. When the putty turns hard, it is less flexible, and becomes more rigid-like, and the cone can't flex the same way as when the putty was new. 

You are already aware of the foam degradation on the inside of the aluminum section of the cone. 

An important parameter for a wave transmission cone is that the impedance of each interface between sections are designed for passing the wave across the boundary, with minimal reflections back up the cone, interfering with the subsequent waves coming down. The same needs to occur at the surround at the bottom of the paper part of the cone. That is why the surround is not replaceable by just any foam surround that physically fits the dimensions.

Hope that clarifies why the sound may be different, if the putty can't be replaced correctly.

pch300, yes, your explanation is appreciated and logical. 

My goal in this has never been to achieve "original" sound, or else I would have demanded the OEM parts. There's a slight problem with that, however; the manufacturer of the equivalent OEM parts does not sell them to repair shops. The cost to do a rebuild of these drivers with new parts is in the thousands, and a very important consideration for me was to absolutely avoid shipping them. Having experienced three different shippers (DHL, FedEx and UPS) absolutely destroy speakers shipped to me, that's not an option. Even custom shippers I have seen with skids having lift trick forks stuck through the box. So, in order to attempt an "original" sound one is forced to go to HHR to get parts, and by necessity spend quite a bit more on rebuild. That's where the choice not to seek spending thousands on this comes into play. 

And, it was the correct choice, imo. Who can say how much degradation would happen to the sound if the putty was dried out? Only a direct comparison to a new unit, kept pristine, would suffice. All this discussion of the sound being altered is moot. The rebuild was successful in the end mostly because of my foam removal. The driver was terribly constrained until I half emptied the cabinet to let the driver work more freely. That changed the sound from the treble on down. I strongly urge anyone with a vintage set to consider whether they wish to do such a fix. Again, this is a Do At Your Own Risk activity, given the potential for there to be asbestos in the foam. 

This is all conjecture, the discussion that I and others are engaging in, as regards the original sound and whether I am achieving anything close to it by using alternative surround and spider. Do I care if the unit has "original" sound? Not at all. Frankly, given my work with the foam removal I saved this speaker. It was on the disappointing side with longer and closer listening than the first impression ("sublime"), and I went at it with a goal to make it much better. I did. So, frankly, I could care less whether I'm achieving original sound. If I'm going to keep a vintage speaker, it had better perform at least in the range of my others. If it's not going to do that, it will go by�e bye. 

This community lives on conjecture. Daily I see people saying, "I think..." in reference to comparison of products that they have never used or never compared actually. This is no different. None of you can say what the original could sound like in comparison to this unit with inexpensive parts. The fact is that with the foam removal, my "version" would likely sound far better than the original. But, again, only a comparison with it would matter, and we're not going to have that. So, moot point. 

The modified speaker just makes it into the category of worthiness to stay, to be used as nice foil to others. When I set up a formidable set like the Kingsound King III electrostatics, there is an adjustment period for soundstage - there always is when changing speaker tech. But, once that accommodation to the radically different dispersion pattern happens, oh, my the King III is in SUCH a different class in terms of refinement. It makes the Ohm sound relatively muddy, even after the fix. But, that, too should be expected. You're not going to get that level of definition and cleanness from a mixed material omni. Not going to happen, especially when, imo, desperation fixes such as putty are used. 

My analysis is that the intent to be novel, to use avant-guarde materials was a top priority, and the putty was a fix. I think the metal would ring like a bell and had to be calmed. Why would anyone produce a speaker like that? Novelty of soundstage, and for sales as putatively superior. You will notice that Ohm speakers today do not use mixed materials. It's just not anywhere close to ideal. And, it doesn't sound close to ideal, either. Between the full range driver and the omni dispersion, it's a fairly distorted result, with less accuracy and more atomized, ballooned soundstage. I accept that as a result of the technology used, and as a pleasing alternative to more traditional speakers. It's fun to listen inside a "bubble" soundstage, or what I call the "mushroom cloud" soundstage. 

If I recall correctly from visual memory, my drivers do not have any putty; they have foam across both sections of metal, titanium and aluminum. I'll have to look again to confirm. So, another missed opportunity to have "original" sound - and to avoid what appears to be an original potential for failure of the driver. Knowing about the putty would I want it? Would I seek it in restoration? I can't say for sure, but with the sound I have, I sure would not seek it. If that's not "original" sound, who cares? I'm not going to sell these or try to showcase them as if restored to original. 

One thing is for sure; as long as that foam would remain jammed into the cabinet to suffocate the driver, this was not a great vintage speaker. Now, with my fix, it is. Let's keep in mind, too, that if a person seeks the HHR restoration, they are not getting the "original" sound anyway. If they were, that would be a tragedy. Purportedly, they are getting a vastly superior sound quality. But, again, unless a speaker is compared directly, no one can say that the difference between them would be great. Theoretically, with the improvements in materials and build the HHR should be noticeably superior, but you're not going to have certainty on that apart from a direct comparison - or perhaps, measurements. Again, this is no comment on the quality and sound of HHR, as I have not used an HHR speaker.

So, basically, my response to the foam, putty, surrounds, spiders, etc. as not yielding the "original" sound is - who cares? Only someone who would theoretically have the OEM parts and seek a perfect reconstruction of it, without any help/parts to improve it. The old speaker is not coming back, and I don't care. I'm not starting a museum, and the only thing that matters in this instance with this set is performance. Now, I have it. What the performance was before, I really do not care.     :) 

+1....oh, 'ell....+10 to the tenth power, @douglas_schroeder ....

(...the world is full of surprises, no? *G*;)....)

"Submitted for your consideration..." as R. Serling used to intone....)

Any vintage speaker that has undergone repair will perform differently than the original when it was new.  That variance will vary from slight to severe, driven by the use of contemporary materials, adhesives, and techniques of restoration.  Unless 'museum level'  restoration protocols are applied, Anything (paintings, sculpture, or speakers) will vary from the original to some degree.

A restored painting, if subjected to minute inspection, will exhibit the restoration.  To expect a speaker to perform Exactly like an new original is fallacy....Unless, of course, you've sent your 'contemporary' Ohms or MBLs in....that's Different.  Having a 'mint', in the box original would be the only fair comparison/contrast test....A~A+/-...*G*

If what you've done or had done pleases one's ears, call it a 'win' and move on.  

There is (imho) the psychoacoustic factor involved....

I've noted when I've been elsewhere for a period of time (on an out-of-town installation for a month as an example), exposed to anything but my own speakers, that they will sound 'different' for awhile....
An hour or two, perhaps a day.....until mind & ears 'snap back' into their 'ruts'.  Visiting an audio convention might prove to be an extreme contrast, depending upon the individual.

I suspect that this scenario might be the root of 'buyers' remorse' occasionally....but, just an observation on my part....your experience likely varies...

Note:

I’d added an additional 'rant ’n rave' to the above, but luckily for y’all I hit the wrong key at the right time and kept your screen from melting like a Dali pocket watch....

You’re welcome.

@mickeyb....I'm not a bank, either....which is why I DIY....

I heard and liked the original F's.....and my wallet froze shut, even back then.
Still like Lotus cars after all these decades....same problem.
The only Porsches' I like are the F1 'cars'.
Even more impractical.....;)