My 5jr's all sound different

Crashdot

Greetings,

Today I decided to hook up all of my newly acquired Polk 5jr's (ported type) to a Rotel speaker switch box to compare them. I have five sets for use as two 5.1 systems (listening room and music studio).

What I discovered is that every set sounds noticeably different from the others, and the differences do not seem to correspond to whether they have fuses or polyswitches, or any other specific component. All drivers have the same model number, and all tweeters are new RD0194. Could it be that not all of the drivers of the same model sound alike?

One set of speakers has modified crossovers which explains why they sound dramatically different and not very good in my opinion, in spite of having upgraded components. Otherwise, I can't detect any pattern with the other sets.

Can anyone suggest what might account for the differences I am hearing, and what I can try to get these speakers to all sound more or less the same?

The only thing I can think of is that some of the crossover components, specifically the capacitors, need to be replaced due to not aging the same way, and that the resistors may not all have the same tolerances or sonic characteristics due to possibly coming from different suppliers during manufacture.

Since I may have to replace a lot of components, I would appreciate any suggestions as to which brand of reasonably priced caps and resistors may sound most similar to the original components used by Polk. I just want these to sound like I remember they did 25 years ago, rather than trying to change the characteristic Polk sound or reinvent them.

Thanks for your consideration.

AudioGenics

.... curious to know what the date of each individual speaker and components
are factory marked. Usually a handwritten or a stamped date and initials. Any identifying marks. document with pictures would be cool.

While the speakers are taken apart for examination / identification check for - loose magnets, loose spiders, solder joints, etc.

Maybe there are previous modifications that were done that you did not know about.

heiney9

Crashdot wrote: »

One set of speakers has modified crossovers which explains why they sound dramatically different and not very good in my opinion, in spite of having upgraded components. .

Please elaborate, that's definitely out of the norm.

Crashdot wrote: »

The only thing I can think of is that some of the crossover components, specifically the capacitors, need to be replaced due to not aging the same way.

Most likely the reason, if as you say everything else is the same. I do know some of the early Monitors with fuses use a different MW driver than later models with and without fuses. But if you say all the drivers are exactly the same.......also sometimes Polk made tweaks on the fly to x-overs so unless each x-over has the exact same component values in the exact same positions then that would cause a variance.

Add all 3 of these things together 1)aging parts 2) different drivers 3) slightly different x-over values and viola.......they sound a little different.

Since I may have to replace a lot of components, I would appreciate any suggestions as to which brand of reasonably priced caps and resistors may sound most similar to the original components used by Polk. I just want these to sound like I remember they did 25 years ago, rather than trying to change the characteristic Polk sound or reinvent them.

Go to a site like Digikey or Mouser and find the absolute cheapest electrolytic caps and absolute cheapest cast resistors they sell. Probably about $1.50 or less total for each speaker. Or you can do it right with better, more modern caps and resistors.

H9

fishbones

Few other possibilities...

They will sound different when you have different/newer/better-quality components in the crossovers - although they shouldn't sound worse? Are the updated crossovers fully broke-in (at least 200 hours on 'em)? Have you checked the wiring to make sure all drivers are properly hooked up in phase? Especially the ones with the updated crossovers? Many polkies have pulled open cabinets on older models (even unmodified ones) and found drivers hooked up out of phase.

What's been said already are strong possibilities too!

Crashdot

AudioGenics wrote: »

.... curious to know what the date of each individual speaker and components are factory marked. Usually a handwritten or a stamped date and initials. Any identifying marks. document with pictures would be cool.

While the speakers are taken apart for examination / identification check for - loose magnets, loose spiders, solder joints, etc.

Maybe there are previous modifications that were done that you did not know about.

I will have to take some time to carefully document the construction of each set as you specify, but from what I can tell only one set has been upgraded, and one was repaired (by me) due to a broken solder joint.

Thanks

Crashdot

heiney9 wrote: »

Please elaborate, that's definitely out of the norm.

The general differences between all sets can be described according to the following characteristics:

Balance of bass vs treble
Output level
Muddiness vs clarity
Wide vs narrow stereo image
Low volume performance

Most likely the reason, if as you say everything else is the same. I do know some of the early Monitors with fuses use a different MW driver than later models with and without fuses. But if you say all the drivers are exactly the same....

This is according to the numbers embossed on the outside, as I haven't examined the inner labels in all sets.

...also sometimes Polk made tweaks on the fly to x-overs so unless each x-over has the exact same component values in the exact same positions then that would cause a variance.

I'll have to unwrap the electrical tape around each set of components and verify the values, but the unmodified crossovers at least appear to be identical on first glance.

Go to a site like Digikey or Mouser and find the absolute cheapest electrolytic caps and absolute cheapest cast resistors they sell. Probably about $1.50 or less total for each speaker. Or you can do it right with better, more modern caps and resistors.

What I want to avoid is the possibility of spending $500 to upgrade all of these, only to find that the upgrades did not improve the sound of the speakers or even made things worse as was the case with the set that someone else modified.

Thanks

fishbones

Have you tried switching the speakers out on the same speaker outputs - to make sure the amp doesn't have something going on with it?

Crashdot

fishbones wrote: »

They will sound different when you have different/newer/better-quality components in the crossovers - although they shouldn't sound worse?

It is entirely possible that the person who upgraded these changed some values, or even crossed some wires, as they sound like something is out of phase. After blind testing a number of times, the "upgraded" set was consistently chosen as the worst sounding of all of the speakers.

Are the updated crossovers fully broke-in (at least 200 hours on 'em)?

That I have no idea about, since I just bought them.

Have you checked the wiring to make sure all drivers are properly hooked up in phase? Especially the ones with the updated crossovers? Many polkies have pulled open cabinets on older models (even unmodified ones) and found drivers hooked up out of phase.

That will be the next thing I check on these, as it definitely sounds like a phase problem.

Another thing I was thinking about would be to take the crossovers from one set of speakers that sounds good to me, and try it out in the other sets. At least it would help to be able to narrow down the issue to just the crossovers if possible.

I did notice that some of the speakers have slightly different fuses, and wonder how much difference the fuse would make to the sound. Additionally, for the sets with polyswitches, would these be likely to cause random variation in sound? I was just going to replace all of the polyswitches, but some of the sets sound good as is and I don't want to spoil that.

I'm somewhat frustrated, as the entire reason that I bought all of these was that I had one set of 5jrs that I really liked, so I was thinking that buying more would result in a timbre matched surround set that agrees with my preferences. Of course I have ended up with the opposite, and now have another big project and the expense required to fix them.

Since I already had 5jr+ and 5B sets that I was planning on getting rid of due to not sounding the way that I prefer, now I'm wondering if these too may be suffering from the same issues. In a previous thread I discussed how my other sets sounded muddy, thin, or had poor imaging, which are the same problems perceived in some sets of the 5jr's. I had previously assumed that there was something specific about the ported 5jr that I just preferred over the other models, but now that idea goes out the window so I will need to reevaluate.

Just to summarize the possible variables suggested so far.

1. Driver date of manufacture or construction materials
2. Tweeters (seems unlikely since I just bought them from Polk)
3. Polyswitches/fuses
4. Crossover component values or age
5. Crossover connections, phase, or design changes
6. Break-in time
7. Damage (loose, broken connections)

Am I missing anything?

heiney9

Crashdot wrote: »

What I want to avoid is the possibility of spending $500 to upgrade all of these, only to find that the upgrades did not improve the sound of the speakers or even made things worse as was the case with the set that someone else modified.

Thanks

That's not what you said in your first post, you said you wanted to use the same parts Polk used to keep them stock. Based on that, I gave you that advice.

Now, moving forward it won't cost you $500 to improve the sound, but you've already said you don;t like the modded one.

Clarity caps
Solen caps
Dayton caps

are all poly caps that are very budget friendly and won't break the bank, but they are signifcantly more cost than the standard 0.85c electrolytic commonly used.

Except you haven't provided any details about the modification or what you don't like about it. What are you comparing it to? The current mish-mash of other Polks you have already stated sound less than satisfactory and all over the board? If so, that's not a proper baseline to compare.

I;d suggest you take a full inventory of each speaker pair with part numbers and crossover values. It's the only way to know for sure.

H9

heiney9

I see you didn't do the mods or really know anything about them (they were already done). Probably time to start from scratch and check the values and trace everything on the PCB to the wires on the drivers to make sure everything is correct. If it sounds as bad as you say, then there is most likely as issue there.

H9

Crashdot

heiney9 wrote: »

That's not what you said in your first post, you said you wanted to use the same parts Polk used to keep them stock. Based on that, I gave you that advice.

What I said was "I would appreciate any suggestions as to which brand of reasonably priced caps and resistors may sound most similar to the original components used by Polk." Basically, I don't want to re-design or re-engineer the speakers because I like the way that they originally sounded, like the two sets we've had since 1985. So, I would like to know what modern components sound the most like the original components did when they were new.

Now, moving forward it won't cost you $500 to improve the sound, but you've already said you don;t like the modded one.

Clarity caps, Solen caps, Dayton caps are all poly caps that are very budget friendly and won't break the bank, but they are signifcantly more cost than the standard 0.85c electrolytic commonly used.

The modded set has Clarity caps and sounds dramatically different from any of the other sets of speakers, so this is why I would like to know what brands may not sound so dissimilar.

Except you haven't provided any details about the modification or what you don't like about it. What are you comparing it to? The current mish-mash of other Polks you have already stated sound less than satisfactory and all over the board? If so, that's not a proper baseline to compare.

I have the following speakers:
RTA12C
5B
5jr+ (passive radiator type)
Five sets of recently aquired 5jr (ported) not including the two sets we bought when they were new.

The RTA12C and two sets of the 5jr's sound very clear with a good balance of bass and treble, with excellent transparency and imaging in my opinion. The RTA12C are lacking kick in the bass, which seems to be due to my amp which does not have sufficient current.

The 5B, 5jr+, and two sets of 5jr's sound muddy and have poor imaging. I don't think the 5B's always sounded bad, since I compared them directly with 5jr's in the store in 1986, and chose the 5B's, so maybe this helps indicate the problem is with old caps.

If I recall correctly, the modified 5jr's were extremely thin sounding and also had poor imaging. Every set of 5jrs seems to have a different amount of bass.

That is about the best that I can describe things, as the sound of a speaker is very subjective. The point is that some of the speakers sound clear, detailed, have a broad stereo image, while others sound either thin or muddy, have nothing going on in the center image wise, and lack detail. In spite of looking identical, they have little in common with regard to how they sound.

I;d suggest you take a full inventory of each speaker pair with part numbers and crossover values. It's the only way to know for sure.

I will definitely have to do that, but what do I do in the case that all of the crossover values and parts are identical as I suspect some of them are?

Thanks

Crashdot

heiney9 wrote: »

I see you didn't do the mods or really know anything about them (they were already done). Probably time to start from scratch and check the values and trace everything on the PCB to the wires on the drivers to make sure everything is correct.

It is true that I didn't do the mods, and honestly I wouldn't have purchased that set of speakers if I had known, because I would rather start from stock than to try to figure out what someone else has done. The previous owner may have purposely changed the way these speakers sound in significant ways to suit their tastes, while I would prefer to have them sound like vintage Polks and make only minor improvements such as replacing the SL-2000's with RD0194's, replacing old polyswitches with new ones, and updating faulty capacitors with ones that function correctly.

FYI, this model has no PCB, but just has the components connected together on the crossover.

Thanks again for your consideration

heiney9

I was on the right track then.....if you want modern equivalents to make them sound like they did in 1985 then the most inexpensive electrolytic caps and cast resistors you can find. Won't cost more that $1.50.

If you use "modern" caps as in poly caps then you won't retain the 1985 sound because caps of today that are available are much better, but won't sound the same as 27 years ago.

The 5jr modded with Clarity caps either was done incorrectly or hasn't fully broken in yet. I used Clarity caps in my 5B's and they have a wonderful, open, non-fatiguing presentation with more solid bass than they ever had before with the old electrolytic caps.

All retaining the Polk signature sound, just better.

H9

heiney9

All 9 sets of speakers have RD0 tweeters I take it? I am getting confused, did you compare them all against each other as in 5B vs 5jr w/port vs 5jr? Or are you simply talking about the different sets of 5jr's?

Crashdot

fishbones wrote: »

Have you tried switching the speakers out on the same speaker outputs - to make sure the amp doesn't have something going on with it?

Hi - all of the speakers were tested from the same set of amplifier outputs.

Thanks

Crashdot

Recently, I was listening to the two sets of 5jrs at my mothers house and decided that I preferred these to the speakers I had at home including Polk RT55i and 5B. At this time, I didn't know anything about capacitors drifting or crossovers needing to be rebuilt, and just concluded that there was something special about the 5jr.

I took a chance and bought a set of 5jrs and 5jr+ on Craigslist without being able to hear them properly, hoping that one or both sets of these would sound as good as my mothers speakers. The 5jrs sounded like the two sets I had grown up with, while the 5jr+ sounded muddy and poorly defined to me.

A couple of months ago, I decided to put all of the speakers that I had at the time side by side for comparison. My conclusion was that the 5jrs sounded better to me than any of my other speakers, so it made sense at the time to get more 5jrs and get rid of the others. After all, the three sets of 5jrs that I had heard so far all sounded great to me, so I didn't have any reason to suspect that other sets would be any different.

After learning more about these speakers, I ordered a set of RD0194s and tried them out in the 5B, 5jr+, and 5jr. The others still didn't sound good to me, but the 5jrs did benefit from the new tweeters.

Since then, I bought four more sets of 5jrs and upgraded the tweeters in all of them so I have five sets with upgraded tweeters. I also happen to have a set of RTA12Cs with fully upgraded crossovers (not by me) and RD0194 tweeters.

After using some of the 5jrs in a 5.1 arrangement for a few weeks, I started to notice differences in output level and clarity, but realized that they would have to be set up side by side and tested with stereo music in order to make any valid comparison.

Yesterday I set up all five sets of 5jrs and compared them, and also performed blind comparisons with assistance. I did not include the 5B, 5jr+, or 12C models in this test since I only wanted to determine if there were differences in the 5jrs.

I mentioned the other models to show I have been listening to vintage Polks since around 1985, had my own 5Bs since 1986, and have owned and/or listened to several other models recently. I had concluded that the specific cabinet dimensions, port, and crossover point used on the 5jrs must have been responsible for the sonic characteristics of those speakers that I like so much, but obviously now it seems that was an incorrect assumption. The good news is that maybe the 5jr+ and 5Bs will sound better if I identify and fix what is wrong with some of the 5jrs, but I guess it all depends on whether I succeed in doing that.

Has anyone else owned more than one set of the same vintage Polk speakers and found them to sound dissimilar?

Cheers

heiney9

What I want to know is how good is your auditory memory that you can unequivocally say you remember what Polk's sounded like 27 years ago? Then compare that memory 27 years later and conclude none of the speakers sound that way?

Not busting your balls, just sort of looking at your statement and trying to reconcile what it is you are looking for in these 27 year old speakers that you think is missing or diminished. 27 years and multiple owners is a lifetime for speakers and all the components age at slightly different rates based on use and typical average life expectancy.

Step one is to verify all the components are the exact same in each speaker
Step two is to verify all the components are part of the original speaker as sold in 1985
Step three is to verify all components are wired properly according to 1985 specs.
Step four is to replace x-over components in every speaker with the like components so as to create a base-line for comparison.
Step five is to forget this headache of a situation

H9

Crashdot

I think what I am saying is that there are three sets that sound the way I remember, or at least the way I want them to sound, while the other sets sound different. I use the same CD that I used in 1986 to test and buy those speakers, and there are very specific things that I listen for that are reproduced well by some of the speakers and not by others. I can't say anything unequivocally, except that some of the speakers sound good to me, and other don't.

This is definitely a headache, and precisely what I was hoping to avoid by buying speakers of all the same type, that I knew I liked, rather than spending thousands on unknown entities from the local Hifi store.

Fail

heiney9

I hear you, like I said the best way is just to start isolating possible differences. Polk always tweaked models on the fly so they may look the same, have the same model # but can have slight differences, which can and will translate into slightly different sound. Add to that the age and the possible extreme situation of worn parts and you could have speakers that sound quite different from each other.

H9

P.s. see my edit

Crashdot

Is it likely that the driver age and treatment could result in the variance in sound?

A few years ago someone decided that it was a good idea to play my mother's 5jr's at maximum volume, which resulted in two of the drivers being physically frozen in the out position. I replaced these the same part number from ebay, and did not percieve any change in the sound of the speakers.

I'm just trying to keep all of the variables in mind and arrange them in order of likelihood so I can come up with a plan of attack. I don't remember signing up to play speaker detective.

Cheers!

TennMan

Where is Mr. Candy when you need him. He could throw a meter or something on those bad boys and tell you why they sound different. With 5 speakers to test he could generate enough charts and graphs that the paperwork would stretch from sea to shining sea. LOL :biggrin: No offense intended. Just having a little fun.

skrol

Polk had a tendency to make changes to speakers without changing the names. I am aware of 3 different XO's for the M5A (2 for the Peerless and 1 for the SL-1000 tweeter). The M5B also underwent a change that impacted its specs (freq range and impedance). At some point they went from fuses to polyswitches. Therefore, there could be differences in the XO even for the same generation M5jr.

You may have to open them up and check the values of the caps and resistors. Also, I have seen different mfg caps of the same value used in XO of the same generation. My M5Bs serial numbers are off by just a few but one has a shiny blue electrolytic cap, the other has a longer black electrolytic cap both are the same value. The different caps may age differently.

Given that the drivers are the same and the cabinets are the same, you could rebuild the XOs with matching components.

Stan

Crashdot

I opened up the crossovers on all of these, and have found the components on the four unmodified crossovers to be identical (each with a 1amp concrete resistor and a 12uf blue capacitor). Since there are no obvious variations in the components printed values, I'm not sure how to proceed other than to replace the caps and resistors in case these old ones have drifted, but I still don't know what brands may sound similar to the other speakers with stock components.

The "upgraded" set with Clarity caps and unknown (long green) resistors had two resistors at different places in the circuit (.47ohm and .5 ohm) rather than the one in the schematic, and the cabinet was packed tight with fiberglass insulation in addition to the original batting material. For these I'll try to get some of the insulation out and put the crossover back to stock specifications to see what happens.

Cheers

heiney9

The biggest issue is the extra insulation...............get rid of it. Second issue is the resistor values are wrong. Either someone replaced the polyswitch if this particular pair isn't fused or perhaps these used peerless tweeters which would normally have 2 resistors in the circuit.

The value of the single resistor in parallel with the tweeter should be 1.3 ohms if your model has a tweeter protection fuse or 1.0 ohm if your model doesn't have the tweeter protection fuse.

Those two issues right there are why they sound like crap. The extra insulation reduces the cabinet volume and the resistor values are off.

If you want original caps, Polk and many other manufacturer's used the least expensive electrolytic caps and cast resistors...........costing pennies on the dolllar and they were not brand specific. At that cost it doesn't make a difference what brand electrolytic you use. Like I stated before go to Mouser or Digikey and find the least expensive electrolytic they sell in your value, same with the cast resistors.

H9

Joe08867

Like you plan on doing already. Get the extra insulation out of there first. I would bet that has a lot to do with the sound issues.

Next update all of those crossovers. Like H9 said the resistors are wrong in the updated set. You are looking for 1.3ohm not .97. The fiberglass isn't helping matters at all.

Crossover drift is a fact. How much depends on storage, use and type. The original caps don't drift to bad unless played with to hard but we are talking about 20+ year old components here.

After you upgrade the caps and let them burn in for 200hrs each you will be in Monitor 5 heaven.

heiney9

Joe08867 wrote: »

After you upgrade the caps and let them burn in for 200hrs each you will be in Monitor 5 heaven.

Remember he wants to use factory stock parts which amount to a few dollars total. Not sure I'd say 'heaven' but atleast there should be consistency of sound across all his 5jr's.

H9

Crashdot

As I mentioned, I am interested in using upgraded components, but would like to use those that won't change the sound too much from what the speakers were designed to sound like. A subtle difference is fine, and having components that will be more stable and more precise is fine, I just want to retain the Polk Audio sound.

Thanks

skrol

In my experience with the RTA11TL, going from the factory electrolytics to Clarity Caps and going to the RDO198 tweeters did not really change the tonal balance of the speaker much at all. It mainly opened the sound stage and got rid of some harshness. They still retain the vintage Polk Audio character. It was a very welcome upgrade for not a lot of $$.
Stan

Crashdot

Did you change the resistors too? If so, I would like to know what you used. The set here with the random resistors and fiberglass packed in has Clarity caps, so I should be able to put correct resistors in the appropriate place and evaluate the results.

Thanks

skrol

I believe I went with Mundorf MR10 resistors.

Tweeter caps were Clarity Cap PX
Woofer cap were Jantzen

Applied Sonic Barrier to the side, top and back wall of the cabinets but not behind the PRs

Applied Dynamat like material to MW and PR baskets.

Here is the link to my RTA11TL project.
http://www.polkaudio.com/forums/showthread.php?t=73017&highlight=RTA11TL+upgrade&page=2

heiney9

Clarity Cap PX series for caps

Mills non-inductive wire wound resistors.

H9