Polk Audio RTiA9 Crossover modification

citation16

Hi again Tony,

The Dynamat is a new idea to me. Good suggestions.
What difference do you hear from that mod ?

But the speaker baskets are screwed right onto the wood of the cabinet... Strange they do not have a rubber rim or something similar to dampen the resonance...? I would be tempted to make some kind of gasket.

I did before use a cheap active crossover biamping old AR9 speakers, without removing the internal Xovers. It did sound better but the active Xover broke and I moved on to something else.

Rewiring the internal is a good idea. I possibly want to find some silver stranded wire for the mids and the high. Or,silver coated copper wire..

I hope Sonic Craft can change the big film caps to smaller ones. Barring that, I would have to put those caps in the cavity of the speaker & connect those caps with long flexible wires to the Xover because it would be too much weight and too cumbersome all together.

The fun is in the journey they say...

F1nut

citation16 wrote: »

I have received the film caps from Sonic Craft to change/replace the 180uf and 220uf caps
.
They are way bigger than anything I saw on this board ( re: F1) and from the VR3


mods.
I wrote to Sonic Craft about getting smaller caps...

You haven't studied well, you cannot fit poly caps on the original boards. You have to get creative, hence the stacking method that Vr3 used and the method I did. Poly caps don't come in small.

Why are you doing only the shunt circuit? The high frequency circuit is the one that matters the most.

citation16

Oh, I have well examined your great and creative work F1 and the work of VR3.
Its just that the largest cap I have received is 3.5'' by 2.2'' !
That seems to be way more in foot print size than what you seem to be using and VR3. What caps did you use or recommend ?
In any case, your incredibly well done Xover ,does not compare to us mortals, to simply replacing a few capacitors, witch I simply want to do for now.
Your work is at the very top end of the bell curve and quite sophisticated..

txcoastal1

VR3 used clarity caps

F1nut

Ok, well the largest value I needed was for the A6 and that was an 82uF for which I used 3 caps in parallel to obtain as Sonicap doesn't have a value that large. The 3 caps still took up a lot of space.

Now, if you study Vr3's pics at the start of this thread you will see he used electrolytic caps for those large shunt circuit values and added bypass caps to "help" improve the performance of the electrolytic caps. The main reason he used electrolytic caps is, as you've discovered, poly caps of those values are quite large.

So, at this point you can see how good your engineering skills are trying to figure out a way to fit those monsters or return them and go with higher quality electrolytic caps for the shunt circuit. I'll mention this again, the high frequency circuit is of much greater importance in obtaining better sound, so you'd want to use poly caps there.

My opinion on bypass caps, they are a very bad idea and should be avoided at all cost.

gp4jesus

An Armaflex-ed RTi A3 mid/woofer:




Also check F1's "Fun w/RTi A speakers" thread for some awesome ideas mounting those big caps.

Tony

citation16

Thank you F1 for your very informative reply. I know understand the compromise made by VR3 using electrolytic caps bypassed with film caps. This also explains the relatively low cost of the VR3 upgrade as I tough VR3 used only film caps. I obviously read what I wanted to read, since they clearly stated using regular caps bypassed with film caps.

So, I will simply put the caps into the speaker cavity and run a wire to the Xover board. The sheer weight of those caps negate adding a layer(s) onto the existing Xover. So much for engineering skills...

Later, F1, I will likely do the high frequency circuit as suggested/recommended.
Its the first time I change caps in a speaker and the first time ever using film capacitors.

I try not to change too much at a time so not to get mixed up as to what does what..

I did change caps and mostly greatly increased capacitance with great sonic results in amplifiers, preamps, phono preamps & motor controls.

Gp4jesus, thank you for the photo and tips. Later I will see how to better install or place the film caps when/after I do other mods to the Xover.

So did you hear a difference with the dynamat on the speaker ?

Yves

gp4jesus

YUP! BTW I used the cheaper, but easier to use, Armaflex. I used a little contact cement to help hold it to the closure sides.

Just like w/my post-mod 'A1 testing, I used the bass-heavy Donald Fagen & I disconnected the jumpers as the tweets mask sounds.

I listened to the modded & unmodded separately. The jumped-out-at-me difference was what DIDN'T come from the modded speaker: all kinds of metallic noises! So put something on those magnets & baskets! If not this time, then next.

'A9 mids XO~: the web site lists the tweet HP ~ - not necessarily the mid LP~. At least that's the case w/the CSi A6*. I got CS to email the schematic*. I understand if that difficult to determine - believe me!

Thnx, you have enough to do! Tony

F1nut

Do not just place the caps loose in the cabinet, they need to be secured somehow.

Yes, Dynamat Xtreme will remove the ringing of the stamped steel.

citation16

This is what I done so far. The caps fit just so in the upper space in the back, above the Xover. Will connect it soon, possibly tonight, as I have to go out of town early tomorrow for a few days. Will use Velcro to hod it so it can be removed easily.

Did only one. The other to follow.
Plan to play the speakers for a number of hours before I compare the speaker with the mod and the speaker with the stock Xover. Will play in mono and toggle back & forth. Hope that works...

gp4jesus

citation16 wrote: »

This is what I done so far. The caps fit just so in the upper space in the back, above the Xover. Will connect it soon, possibly tonight, as I have to go out of town early tomorrow for a few days. Will use Velcro to hod it so it can be removed easily.

Great(!) you got something done!! Bummer you hafta "press pause" mid stride.

citation16 wrote: »

Did only one. The other to follow. Plan to play the speakers for a number of hours before I compare the speaker with the mod and the speaker with the stock Xover.

Exactly what I do - DYING to learn what you hear.

citation16 wrote: »

Will play in mono and toggle back & forth. Hope that works...

why not?!

Can't wait for your return, Tony

PS: PU some Armaflex Lowe's or HD on your home from trip.

citation16

I could not resist finishing the connection with the films capacitors on one speaker..

I was really doubtful if I would ever hear a difference , just having modified only one speaker.

I watched a Netflix documentary that I was half way into previously.
Right away I seem to notice that the man speaking had more air around his voice, more depth of field and a more precise image.
I then later left the system on with the TV for another hour or so.

Then I played the JungSon Impression CD player (transistor output) using a demo disk made by a well know high end speaker manufacturer.
The preamp is a Carey modified (more capacitors..) dual mono tube SLP-03 driving 2 amplifiers Dussun V8 at each 250 watts/channel at 8 ohm.

Although I modified only one speaker and played both speakers, the difference became quite apparent:
- The sound sort of now came out of the box, from being much more confined to the speaker boxes.
- There is far more air and a wider & higher sound stage & deeper
- The speakers do not easily vibrate as before, I heard no vibrations, but did not play it extra loud..
- It is a livelier and richer sound - much more body & substance
- The bass is cleaner and deeper and more realistic
- There is more detail, more nuance, more layers in the sound
- The voice is less shrill, rather well seated

I cant wait to install the film capacitors in the other speaker & revisit the above comments.
The dialectic capacitors of 180 uf and 220 uf I removed really seem cheap and inconsequential and have no label. Likely , anything remotely better would make a difference. Later I will do the high frequency caps as recommended by F1.

I have to order some Dynamat Xtreme or something similar- that is another project :-) I have some deadening material I bought for another project, but it does not stick very well.

I never modded speaker Xovers before and this is an incredible revelation. By upgrading the Xover, it really opens up the sound.

More later, when I modify the other speaker late next week I hope. Thank you all for your great help.

Yves

F1nut

And yet there are those who will say it's all in your head......LOL

lightman1

F1nut wrote: »

And yet there are those who will say it's all in your head......LOL

Along with the voices that keep saying
"Doooo iiiiiit........"

Congrats on your ear opening experience.
Keep up the good work.

citation16

Thank you for your feedback.

OMG I just went to the web site www.humblehomemadehifi.com/cap.html
They compare different brands and quality of film capacitors. I wish I had read that before so I could have possibly bought more expensive caps and mortgaged the house

F1 notes, the high grequency caps are the most important. I wonder in what way; just very curious...and ignorant...will the midrange sound also diffetent?

I forgot to note down the values of the 2 smaller caps in the RTiA9 Xover. Does anyone know this info? I am out of town and wonder how much the high rated film caps cost for the high frequency small caps.

In any case, the review of the film caps and mention of how much they are better than the electrolitic caps , confirms my findings so far and my sanity ( or part of it...).

Changeing the Xover caps seems to make as big or more of a difference than using tube gear at a fraction of the cost.

gp4jesus

citation16 wrote: »

Right away I seem to notice that the man speaking had more air around his voice, more depth of field and a more precise image....

Although I modified only one speaker and played both speakers, the difference became quite apparent:
- The sound sort of now came out of the box, from being much more confined to the speaker boxes.
- There is far more air and a wider & higher sound stage & deeper
- The speakers do not easily vibrate as before, I heard no vibrations, but did not play it extra loud..
- It is a livelier and richer sound - much more body & substance
- The bass is cleaner and deeper and more realistic
- There is more detail, more nuance, more layers in the sound
- The voice is less shrill, rather well seated

Yves

C16 (Luke): "You know, I did feel something."
F1&gp4(Obi-Wan): "You've taken your first step into a larger universe."

citation16

For sure, I have taken my first step into a larger universe

citation16

My apologies for not reporting earlier, since I did change the capacitors in both speakers and also changed the mid and high frequency caps. Since then, the sound is getting better and better and is totally amazing. Well worth spending about $500 US .

F1nut

Indeed, good sir. Give those Mundorf caps a good 300 hours to settle down.

xfactor

In the RTiA9's, Does anyone know if they addressed "BSC" in any way "somehow", like maybe in the crossover? And/Or, has anyone tried to address this physically with anything, like Spacers on the three woofers? Because that "should", pull the imaging way tighter than currently possible. They do sound much better after lifting them off of the floor 14" and with a "8-degree", forward tilt! Plus a little vibration damping. They still "ring" a lot though. And the ringing "is", in the cabinet itself. I've had them in three different rooms now. I was thinking it might be the "Rotel" amps "at first", but no.
They seemed to "Open Up" once I gave them amps with a lot of head-room also. Currently they are "Bi-amped" with two "Nakamichi", "Pa-7" amps.
Anyone?

gp4jesus

Did you connect your Nak Pa-7s one amp to each channel? Or one to the tops and the other to the bottoms?

And what model Rotel(s) did you try before the PA-7s?

Thnx

xfactor

When I Bi-amp, the best and as far as I am concerned, "Most logical" way, is to use one channel from an two-channel amp. Utilizing one channel from that amp to power the same thing on either side. As in,"Mid+mid, tweeter+tweeter and etc." If you try the other way? Unless the amplifiers are really, really well matched and further, they have been "Calibrated" not just together. But actually adjusting each "against" the "other".
If not?.. You will have at the least some, "Imaging" problems. If not a horrible mess!
But if there is something you think I "am", OR "may", be missing? Please let me know!
With those? Several different amps over the two years I have had them. First with "4", of the old "HK", "775" mono-blocks. B"165Wpc @8ohm". But those amps always sounded "sweeter", and "easier", with a lower Ohm load. So I went to the "Rotel" amps. first two "RB-985"., 200Wpc @8ohm. Then I used four channels of a RB-1095, placing a resistor as the load on the fifth channel, just to do so with any Class D, or A/B topology. So again the same WPC rating but a much larger supply.
Then I tried the RMB-1575, "Class D", I even tried that amp, wired into a, "4ohm" config. "and it was a little better". But they sounded not just "Bright", but also "Thin" at times even with being "Bi-amped", 1000Wpc @4Ohm. The cab's, "ringing" seemed to increase as well. It became more, "Metallic" in nature. The m-509's "Onkyo" were too 'Under-driven" to get into their "sweet-spot", So then, M-508 Grand Integra's. That sounded nice overall. But made the speakers inherent, "flaws", stand-out too much.
So then the "Nak's". First a pair of the Pa-7iiE which I didn't like at all on the top-end. . The the older but sweeter, Pa-7, "Gen 2". Right now I actually have a Pa-7iiE on the bottom end and a reg. Pa-7 on the top. And it's the best I think they have sounded.
I have not opened these up yet OR modified anything about them. "Yet", But that will come.
I purchased these for my home theatre. they did work very well for that. But someone told me what Polk had put into the R&D of these. And I've seen the results. Especially what they put into the enclosures. I do happen to "Build" speakers.....but of a, "Very" different type. "Dipole" mainly. "
But, That's for another discussion".
These to my eye, on the outside? They are a work of art. Period.
So they are kind of a challenge..To me. Because I KNOW these could be amazing. "For a (Point-Source)"! anyway!
Math-wise they work. They ring because they didn't use enough layers while laminating the sides together. Also by not alternating the layers with damping materials. But I would bet that was the fault of the "Bean Counters" once they went into production.
"Why they did not address any (BSC) at all? Or even try a small radius on the front/rear face edges to minimize waves-defracting from those sharp "90's"? And after spending all of that on R&D?" UNBELIEVABLE! Anyway..
I do make "Speaker Cables" too. So these are using a set with a 10AWG silver plated copper , fine-stranded. And then two "18AWG" solid, single conductors, of pure silver wound around the 10awg in a helix, for each of the eight needed for bi-amping. That helped both the imaging and noise-floor greatly. Plus the separation is very nice as well. But i never had a speaker that benefited so by leaning it forward "8 degree's". Thats a lot!
What do you think the most beneficial sise-to-side, spacing, "L+R" is for these "d'appolito", array , config. speakers?
Thanks for the interest and help!
S.

VR3

Rtia9/Csia6 with laser printed substrates. Was able to drop the large inductor on the rtia9 below the substrates above and below, very secure!

pitdogg2

That's a lot of copper!

VR3

Air cores are so much better than iron core.. but they use lots of copper! biiggguns!

gp4jesus

@VR3

From what material or substance are the separation pieces?

Your upgrades - all that attention to detail. So pretty just to “hide” inside. Fortunately, they’re prettier for ears!

VR3

Thank you!

Acetal/delrin

gp4jesus

VR3 wrote: »

Thank you!

Acetal/delrin

I figured non-conductive. Looks like aluminum and about as strong?

VR3

It is a metal replacement plastic.. Pretty much unbreakable

gp4jesus

Where do you get it? I think I’d like some for BP plates. Difficult to cut and/or fit?