Underwhelmed with the highs on my RT55i speakers

Strong_Lead

I picked up a pair of RT55i off of CL for ~ $100. The "demo" consisted of listening to the speakers hooked up to a low-end receiver at the front of a packed garage that faced a busy street in San Francisco. For that price, I was happy that all the woofers and tweeters worked.

After reading all the rave reviews for the speakers, I found myself disappointed with the performance in the living room. While they have a nice, warm sound, the highs have neither clarity nor detail. Sound stage was nothing like others describe, but that could be a function of the (corner) room placement.

Two questions:

1. How much would a crossover update/upgrade help brighten up and clarify the highs? The amount of (expected) improvement, will drive the budget.
2. Assuming it will help with my complaint, where do I find information explaining the why & how for the upgrade? I found a very helpful thread showing the components and mods to the x-over board, but I understand nothing about the component selection or any other design considerations.

I have a brother-in-law who is an EE, and he does board level diagnosis & repairs for combat-ready naval aircraft equipment. He'll be around for Christmas and is more than capable of doing the work, but we have no basis for substituting components based on availability and performance.

The RT55 schematic in the wiring schematic thread does not d/l using either Firefox or Chrome.

Here are the components I've gleaned from the refresh thread:

• 2 ea. Mills 3.5 Ohm 12W Non-Inductive Resistor. The partsconnexion price for the 12W MRA-12(shown) & the 50W MRC-50 are essentially the same.
• 2 ea. Mills 2 Ohm 12W Non-Inductive Resistor (same pricing dynamics)
• 2 ea. Solen 16uF 400V Polypropylene Capacitor
• 4 ea. (2x per board) 1.5uf Clarity PX in parallel for C1,
• 2 ea. 9.0uf Clarity PX for C3 in the high-pass

1. Is there any advantage/disadvantage to using resistors that have a higher power rating?
2. I cannot find a 9.0 uf cap. If I combine two in parallel to approach 9.0, should I go a little over or under?
3. Which caps are the most critical, ie. are there any particular caps I should upgrade?

F1nut

It's possible your tweeters are not working.

Don't use Solen or Clarity PX caps, use Sonicap. http://www.soniccraft.com/index.php/sonicap-gen-c-301_49_50

The Mills 12 watt are fine.

pitdogg2

Cardas Solder can be had for a very fair price. If both those (I have not scene schematic) caps are in the same circuit there is no reason not to go 3uf instead if 2X 1.5uf. It is always better to get as close as possible the the end value. So you really do not want a 5uf and a 20uf to make the end value of 25uf. If it comes out that you use two 12uf that would be much better as its still within +/- % of value.

Sonicap Gen 1 is all you need.

agfrost

Sonicap Platinum is only available in smaller values/is significantly more $$ than the Gen 1--I'm unaware of anyone who's used them in a speaker crossover.

If you're ordering from Soniccraft, order some Cardas Quad Eutectic (QE); it's in their 'accessories' page. Quality solder and easy to work with. Stay away from non-leaded solder, it's a pain to work with.

ken brydson

55i's while getting older may not need the crossovers done quite yet. Are the binding straps installed between the top and bottom posts? If so are they tight? Maybe check the leads on the tweeters. Just my .02...

heiney9

You don't mention what gear you are running, an AVR won't cut it if you are looking for the best performance. We know nothing about your room set-up, stands, placement, source material, etc. All are factors in making them sound their best.

I have pair of RT25i's and they sound superb on every level. Way better than a small speaker should.

H9

Strong_Lead

Sorry guys, when Sonicap closed for the holidays, I put this thread to the side to worry about my BBQ/smoker rebuild project (another story for another time). Now that they're back, I can pull the trigger on buying the upgrade components.

@ Ken:
Yeah, the terminals are good, and the drivers work. I get highs; they're just not crisp.

@ Heiney9:
I've tried them in two configurations. The first configuration was really tough: the corner of the living room, either side of the TV, 31" off the ground. Driver was a Pioneer VSX-1124K (AVR)

I've sense replaced the RT-55i with a pair of RTA-12C that sound MUCH better!

Currently, I have the RT-55i's on my desk as PC speakers, driven by an old Sony STR-DE598 (AVR), and I can hear a lot more detail that got lost in the larger room. The clean highs are still missing, and the speakers are too close to really hear much in the way of sound stage. I eventually plan to move the pair to the kitchen with a high mount (open air shelf) ~ 6-1/2' off the floor.

@F1nut:
Normally, I find declarative statements without supporting evidence quite annoying. Noting how many helpful responses you've given to various questions, I decided to search on Sonicap before getting annoyed. Well, I can see why you need not explain your recommendation! They look like an excellent recommendation that maximizes bang-for-buck, which make them a good fit for the quality of speaker. As an added bonus, I like the fact that they have all the sizes I need so I don't have to worry about clashing sonic characteristics.

The crossover refresh thread used two 1.5 uf caps in parallel. Is there any reason to keep two equal-sized caps rather than a single 3.0 uf cap? Likewise, should I still use two caps but split them into different values (that total 3.0 uf)?

One would think something as straightforward as solder could be easy, but audiophiles know how to blow the budget looking for that final .1% improvement. While I know I don't need the Mundorf "Silver/Gold Supreme" solder (at a mere $111 for 100g), what kind of solder matches the quality level of the caps (and resistors) I'm using?

Without the circuit, it's hard to tell which cap/resistor works on which part of the circuit. Based on relative values, somebody may be able to infer the functions of the caps... Are all the caps equally important, or should I budget more $ for a particular cap to upgrade to Sonicap Platinum?

Thanks for sharing your expertise!

gp4jesus

agfrost wrote: »

If you're ordering from Soniccraft, order some Cardas Quad Eutectic* (QE); it's in their 'accessories' page. Quality solder and easy to work with.

+2! I'll never use the cheap stuff as long as this* is available. Melts about 100 degrees lower & sets up much faster.