RTi6 Crossover Rebuild

ALL212

Really....:D

ALL212

I didn't like the way the bass was on my last round. I had a couple sheets of Sonic Barrier 3/4" 3-Layer Damping Material w/PSA 18" x 24" (Parts Express) left over from the DQ-10 cabinet.

I pulled the speakers and the crossover and used a sheet and a half of that damping material in the cabinets - pulled all of the fiberglass batting I had put in there out.

You don't have to cover every nook and cranny with this stuff - get the sides roughed in with a full sheet cut into quarters. Cut the 1/2 sheet into long quarters and use that in the top and bottom. This stuff has some pretty aggressive adhesive on it but once it's down you need to leave it - trying to reposition it doesn't work well - the adhesive picks up anything in the box - leftover batting, dust - anything - and then won't stick well on the second try.

I'm much happier with the bass - could be my ears are just happier because now they are consistantly damped - not just randomly filled with batting.

These speakers would probably benefit from a piece of wood attaching the two sides together. It wouldn't have to be pretty and you'd have to be careful where it goes so you could put the woofer back in. Get it close and then just glue it in. I'm a wuss - it's cold out so I'm not cutting wood...:p

Face

I would use hot glue or something similar to hold down the Sonic Barrier, it's adhesive isn't that strong.

Tuan

For the RTi6 crossover, if you use 15uF capacitor instead of the 12uF capacitor, your polk audio speaker will sound better.

Face

Tuan wrote: »

For the RTi6 crossover, if you use 15uF capacitor instead of the 12uF capacitor, your polk audio speaker will sound better.

How's that?

By crossing the tweeter too low you're adding distortion, a hump in frequency response, and can shorten the life of the tweeter.

Tuan

The 12uF of RTi6 crossover is not a capacitor for the tweeter.This capacitor is connected series with a 5.5 Ohm resistor after 1.16 mH iron conductor for the woofer. For me this looks like an impedance equalization for the woofer.If you already replaced all Polk Audio capacitors with metallized polypropylene capacitors using the values marked on these capacitors, your RTi6 may not sound best. Using 15uF instead of 12uF, your RTi6 will sound better (more balance, tweeter less harsh, more bass).If you use a digital meter to measure the capacitances of RTi6 electrolytic capacitors you will have about 25% different capacitances ( not close to the values marked on electrolytic capacitors).The good capacitance of capacitor for tweeter is 8.2uF. I did not replace resistors because RTi6 resistors are good( your RTi6 will not sound better by replacing these resistors).

ben62670

So Tuan why didn't Polk use a 15uf cap? I trust face and the engineers.

Tuan

I do not know why.I used digital meter to measure the capacitance of RTi6 12uF electrolytic capacitor the reading was about 15uF.

ben62670

And that is why we upgrade the caps. The stock ones a mediocre to poor. The sand cast resistors suck. Use Mills.

Tuan

I also measured the inductance of the sand cast resistors, the inductance was too small.
The capacitors for the tweeter are 0.47uF and 7.5uF.I think 0.47uF is a bypass capacitor.This capacitor will make the tweeter sound more "concert hall acoustics".
http://www.partsconnexion.com/capacitor_film_visrod.html

ben62670

Do two speakers with the same frequency plots sound the same? No it depends on the material used. Don't get hung up on the little bit we can measure.
Ben

ALL212

Tuan wrote: »

For the RTi6 crossover, if you use 15uF capacitor instead of the 12uF capacitor, your polk audio speaker will sound better.

Tuan,

This might sound petty but have you actually done this and heard it or is this all theory?

Aaron

Tuan

I have done this with my RTi6 speakers.I have replaced the 12uF electrolytic capacitors with 12uF metallized polypropylene ones(I have used Solen capacitors and I know that my Solen capacitors can not beat your ClarityCap capacitors in term of sound quality) and I was not happy with modified RTi6 speakers.Sound of speakers was not balance,bass was not strong like some reviews about RTi6, and treble was a little bit harsh.I know that something is wrong in RTi6 crossover.I decided to change the value of 12uF capacittor of one speaker so that I can compare two speakers side by side using the same amplifier.It was difficult but finally I found that I only need to use 15uF(not 16uF) capacitor instead of 12uF and now RTi6 speaker sound so good(a lot better than the one with 12uF).Now I am so happy with the sound of my RTi6 speakers even when I connect them with the 30w per channel AVR154 Harman Kardon receiver,RTi6 speakers sound imagine.( I think Polk Audio company should hire me to work for them!)

heiney9

Actually Tuan, I've used Sonicaps, Clarity Caps and Solen caps. The Solens came in last as they are much more forward and are grainy and little closed in compared to the other 2 brands. They are certainly better than the stock electrolytics and they aren't a poor cap, just don't perform near as well as the Clarity which are smoother, more linear and more open. Sonicaps are even better.

H9

Tuan

heiney9
Thank you for your opinion.I will buy some ClarityCap capacitors for my Polk Audio RT35 and Energy Connoissuer C-3 speakers.

Tuan

For my modified RTi6 crossover, I also use 3 Ohm resistor instead of 2.5 Ohm.This change will make the balance between the tweeter and the woofer.

Tuan

Aaron,
To me, RTi6 speakers are not enough bass.Do you agree with me about this?
Unless you want your RTi6 crossover close to Polk Audio design you can change the capacitors only.When I modify my RTi6 crossover I do not only change the capacitors but also change value of capacitors and resistors.These are more complicate since you need to know well about crossover design for specific drivers.
These are for my modified RTi6 speakers and I really like it:

used 4.7uF instead of 7.5uF

---

15uF

---

12uF

---

2.7Ohm

---

5.5Ohm

---

3.0Ohm

---

2.5Ohm

Tuan

Face

Are you using software or a microphone to aid you in these changes?

Tuan

Face,
Yes. Now the sound of my modified RTi6 speakers are very good(to me they sound alot better than the original ones).If you like more treble, you may not need to replace the 2.5Ohm resistor in case some of bad CD recordings. Bass now improved alot.

Tuan

ALL212

Sounds like I'll make some changes on my next crossover rebuild...!

Face

I would take Tuan's suggestions with a grain of salt.

Tuan

Aaron,
There is more bass without distortion after I modified my RTi6 speakers.I may keep 2.5Ohm resistor because I like more treble.

huskerpolkfan

i have question do u think i should upgrade the crossover in mind monotior 10b with the sl 3000 one sound clean then the left channel

ALL212

huskerpolkfan wrote: »

i have question do u think i should upgrade the crossover in mind monotior 10b with the sl 3000 one sound clean then the left channel

I've got to leave this one for those that know this speaker and tweeter. I have no experience with either.

Tuan

Aaron,
Finally, I have modified my RTi6. My RTi6 different components are:
15uF instead of 12uF
2.7Ohm

---

5.5Ohm
3Ohm

---

2.5Ohm

Deep bass, very good midrange and treble.
I think my RTi6 will sound even better if I have some Clarity Cap capacitors.

Tuan

ben62670

Face wrote: »

I would take Tuan's suggestions with a grain of salt.

I would take the suggestion with a block of salt.

Tuan

ben62670,
I do not want to suggest anyone about this.I only want to show Aaron that I have different way to modify my RTi6 speaker.I am sure that my modified RTi6 speakers now sound better than any RTi6 speakers.My brother gave these RTi6 speakers to me after one year using them and told me that these speakers were not enough bass, midrange was too much and he did not like their treble.He asked me if I could modify the crossover so they could sound better.He knows that I have been building speaker since I was 18, now I am 43.I may be lucky with this but I at least I can do something better.

Tuan

ben62670

Setting may play a part in your setting. I know that I stray from the Polk designs before when building custom SDA's. They were tuned to sound great in one enviorment and completely flopped in another. I apologize about being so blunt, but I strongly recomend against the Polk design.
Ben

Tuan

First, I have the same opinion that I should stick with original design.That was why I only changed the capacitors only but I was still not happy about the sound of RTi6.I decided to modify the crossover the way I test.Now by changing only values of 3 components(2 resistors and 1 capacitor) my RTi6 speakers sound so good for classical, jazz and even pop music.My modified RTi6 sounds alot better than before.2.5Ohm resistor for the tweeter was a bit small.The tweeter sound louder than the woofer.My Harman Kardon HK3490 may cook the tweeter very well done in 3 minutes at high volume.
This is my opinion.To me, it is always fun to make good speakers.For RTi6 I like the design and quality of the box.I am living in Maple Leaf country.This may be my last post reply to you.Good luck Aaron and everyone!

Tuan

Roamingrasta

ALL212 and Tuan,
While searching for repair/parts solutions for my RTi6 mid/woofer I saw your posts on crossover mods. Very nice! When I see what you’ve done I find myself wanting to make some changes to my speakers:
Front: Rti6
Front: CSi3
Rear: FXi3
SW: Definitive SuperCube III
This system is our secondary, our main system is a physically smaller system by Aperion (sweet HT sound but can’t blast if for a party) and the wife won on what we put in the family room. We are moving into a new house that we have a dedicated game/multimedia room and after blowing a speaker (leant it to a friend for their party) in the RTi6 I would like to do a refresh to the enclosures. What I’m thinking of doing is either replacing the mid/woofer drivers in both boxes with newer technology . . . . crossover’s and new (higher end) drivers. Or, buying a set of RTi A5’s and expanding this system to a 7.1.
What do you think . . . I’m still going to do CO the mods on the RTI.