Can we improve or modify the RT800?

gmcman

Seems there are mods for the LSi and the SDA and surely others, but before I go and spend $$$ on more speakers...I want to see what the possibilities are for these 800's

Not that I don't mind more toys, I feel the design of the RT800 has potential for music as well as HT. I'm currently contemplating LSi9's or SDA's but I want these to be part of the equation if possible.

I started a post, (8 years ago) when I joined for that particular purpose....http://www.polkaudio.com/forums/showthread.php?8856-RT3000-x-over-in-RT800&highlight=rt800+mod Fast forward to present, marrige, couple kids...where does the time go. I still have those speakers and given their age, What can be done to really open these up for critical 2ch listening?

AFAIK, the RT800 uses a real-time array and the RT3000 uses a cascade array, has anyone tried a 3000 X-over in a 800?

I agree that the 800 can get bright at high volumes given their intended HT purpose, but are no slouch for music...what can we do to make them better?

Tweeter change, crossover rebuild...not sure.
I'm currently using a Denon AVR3300 as my receiver/main amp, shotgun bi-wire of AQ Crystal, Mirage 10" sub.

Face

Replace the tweeter cap with a Claritycap SA and tweeter resistor with a Mills, that will make them sound better an tone down the brightness.

JimAckley

Face, forgive me for not having any experience with the RT800's xover, but why only mod the tweeter circuit and not the rest?

jbooker82

Probably because it would make the most difference in trying to reduce the brightness and you wouldn't have near as much money invested as a fully rebuilt cross over.

Face

Plus, there's only a coil on the woofer, nothing else.

You would need a 2.2uf cap, 8.2uf cap, and 1.0 ohm resistor per RT800.

Sonic Caps and Claritycap PX's would also work. The PX series would probably be the easiest to use due to their size.

gmcman

Would it be possible and/or advantageous to raise the crossover point on say the top woofer? I wonder if that would provide a more seamless blend?

I also have a few sheets of dynomat laying around.

Face

Leave the crossover points be unless you know what you're doing.

gmcman

Face wrote: »

Leave the crossover points be unless you know what you're doing.

I know just enough about this to be dangerous.....:)

Seriously though....just an idea.

Are there newer tweeters that will fit? Also, if a full x-over mod is the way to go then I don't mind tossing in the $$$, since if it may work as well or nearly as well as a mod to a LSi9, then I'm still ahead of the game.

jbooker82

I had my full rebuilds done on my RTI A7's and CSI A4 by trey. It made them sound better. Kind of just a tinkering thing. Why leave them factroy right?

Face

gmcman wrote: »

Are there newer tweeters that will fit? Also, if a full x-over mod is the way to go then I don't mind tossing in the $$$, since if it may work as well or nearly as well as a mod to a LSi9, then I'm still ahead of the game.

Nope, and in fact, I'm not even sure if replacements are available any longer.

gmcman

So I went and moved the speakers around a little today, was able to get the right away from the wall...was about 3" now it's almost 2 1/2'.

I put on a few albums..Rumors and Brothers in Arms, and after I really started to pay attention to the highs.

Having been listening to these speakers for about 12 years...it's kinda hard to criticize them when I haven't done an A/B test with others. However I can say now that without a doubt, the highs are way too high....just doesn't seem natural. Granted i'm just not now noticing this but i'm just more overly-critical getting back into vinyl, Mcvie's vocals were shrilling and I wasn't playing it too loud.

For HT they are great, and I don't fault this but it's definately time to either modify these or just get some other speakers.

Is there absoulutely zero chance of getting a ring-radiator to fit in these, with minor cosmetic surgery? If this is possible, what steps are needed? I know there are different models of this tweeter, some or one is in a larger housing.

Can the silk dome tweeter even be modified to get in the ballpark of the ring radiator?

Face

The crossover and voicing make more of a difference than the dome material. Even if you get them to fit, you'd have to re-design the crossover and you'll likely cause more harm than good.

Follow the advice in post #2 and if you want to experiment, also pick up a pair of 1.25 and 1.5 ohm resistors and see which you like best. I guarantee replacing the caps with the suggestions above will help smooth them out.

gmcman

Should have put this in the DIY forum, mods feel free to move.

gmcman

I don't keep up on where the best place is to get the caps from, what do you recommend?

Also, are these the better caps or are there others..or will I notice a difference? Seems they are smaller so price should be negligible.

Thanks and I will try the caps/resistor first.

Face

The Claritycaps are available from http://www.madisoundspeakerstore.com/claritycap-caps/ and Mills resistors are available from Parts Express: http://www.parts-express.com/wizards/searchResults.cfm?srchExt=Mfg&srchMfg=253&Manufacturer=Mills%20Resistor

gmcman

What about applying Dynamat to the interior? I know it doesn't take much but for a speaker do I need to cover all of the exterior panels...obviously from the inside.

I haven't had the time to fondle any high-end speakers but with some bass guitar these cases resonate quite alot. Being near my RPTV it seems that it may be making that TV sing right along...I know for certain I can feel the speakers vibrating at relatively low volumes, just curious if Dynamat has been proven to help towers like these.

gmcman

Looking at a schematic for the rt 800, are there only 2 capacitors or 3 for the tweeter?

gmcman

Here's the schematic....what is at C2, is this a 3rd cap? I'm assuming it's irrelavant for what we're doing?

Joe08867

Looking at the schematic it looks like you have three caps on the tweeter. You best bet would be to take the crossover out and look directly at it. Maybe take a pic and post it here so we can help with identifying the different caps.

Face

The. 22 is a bypass and should not be replaced when upgrading.

Joe08867

Nice catch Face, I thought I read 2.2 not .22 so I thought it was another worthwhile cap not a bypass.

Looks like the original answer Face gave you was the correct answer. Sorry about that Face.

Get some Clarity Caps and Mills resistors and be in audio heaven.

gmcman

I did order what Face recommended...many thanks.

Here's the X-over out of mine:

gmcman

All the parts arrived today and I just want to clarify the install.

I remove the yellow 2.2 and the black 8, replace with the 8.2.

Remove the white ceramic resistor and replace with the mills.

Nothing else gets removed?

Thanks again.

Face

Replace resistor.

Remove the 2.2uf cap, replace with new 2.2uf.

Remove the small red cap above the 2.2uf, nothing goes in it's place. Remove the 8uf, replace with 8.2uf cap.

gmcman

I left out the "replace 2.2", long day at work. Wasn't sure about the small red one.
Thanks again.

Inspector 24

Very interested in this thread, I've got two sets of 800i's and one 1000i which are even brighter And harsher than the 800i's. Perhaps they could benefit from the same
mods?? Can't wait to hear about the results!

gmcman

I will need to extend the lead of the large cap, can this be accomplished by using the same gauge solid strand wire and soldering together?

Face

That's fine, you can use solid core too.

Are you referring to the 8.2uf? If so, you can also use the pads where you removed the bypass cap.

gmcman

Face wrote: »

That's fine, you can use solid core too.

Yeah.....didn't I say that....ha.

Which pads are you referring to? Yes it's the 8.2uF cap and it looks like I need to mount it above the small inductor.

I have 4" of clearance to the power port so I can flip the board over and shave the plastic posts slightly or keep it turned the the same as factory and extend the posts, which the latter is prob the easiest.

gmcman

I was able to finish one x-over last night and get everything back together. I originally wanted to have the board turned over in the same manner as it was by adding 4 hollow posts and longer screws, but to keep it simple I flipped the board over and I had just barely enough room to the power port. By barely I mean the large cap touches at the same time as the plate reaches the cabinet.

I tilted the cap slightly before I glued it to allow for this. The inside lead on the large cap barely reaches, the inside lead is the one that makes a straight line for the hole, the outside lead I had some extra wiggle room.

I suppose if anyone does this to shave 1/8-1/4" from the posts and you will be able to glue the caps flush.

To allow access to the hole for the large cap, I raised the small cap on some single-sided adhesive foam. I was going to rest it on the old 2.2uf yellow cap but I pierced it with the x-acto knife, I think I will remove the yellow one also on the R speaker.

Just for reference, the stock board.







This is the slight angle to allow for port clearance, or lack thereof.



I don't know if this needs a burn-in time, first impressions are it's definately different. A little difficult to tell by just listening to a few LP's since naturally not all info is the same on both channels but the highs are slightly muted from the right. After listening to these speakers for so long i'm just used to the pronounced treble but hearing some SDA-2A's last week, I know now at least what a good tweeter should sound like....I think it has at least turned in that direction.

The highs are definately smoother, I can hear more detail in the upper ranges without the slight crackling or breaking up the stock setup was. Listening to Rumors, Mcvie's highs in "You Make Loving Fun" were almost shrilling but are more tamed now.

I don't know what to expect in the next 100 hours or so but so far it seems to have taken a step in the right direction. Something else I noticed is the mids definately pop out, perhaps this could be from the tamed highs or the fact my DL-301 II hasn't broken in yet and it has a very forward midrange when new...prob a little of both, not sure.

I guess if it stays too warm I could go down a value in the Mills resistor, but for now I like it.

I wanted to add, there's enough wire to leave the leads attached to the drivers, so bring the speaker to the bench. The tweeter lead looks like it could be a real PITA to thread back through that small hole.

Inspector 24

Any updates? Mods worth it?