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RP 8000 F Modification Project


MicroMara
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In these pandemic days of holidays I want offer a contribution for speakers modify. I'm waiting for tweeters, so for now I've setup all that it need for measurement for understand if the damping has a good response.

For now I'm testing the rear little bookshelf, these are the result (with REW 5). 

This is a near field measurement at few cm from speaker, on left you can see the little images of others, with mic horizontal at 1 mt and vertical mic at 1 mt, and as you see the mic receive the return of the room waves. The next step is modify 1 speaker and test the diference with the original.

 

book.jpg

Edited by Crab2k
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The result is very good, the frequency near 38hz gained a lot. The measurements are made with mic at about 1 cm from woofers, so no distortion from room. 

For more information about this, you could read this very interesting site, about loudspeakers, phase and so on:

http://www.claudionegro.com/

Thank you very much for the suggestions.

Edited by Crab2k
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1 hour ago, Crab2k said:

The result is very good, the frequency near 38hz gained a lot. The measurements are made with mic at about 1 cm from woofers, so no distortion from room. 

For more information about this, you could read this very interesting site, about loudspeakers, phase and so on:

http://www.claudionegro.com/

Thank you very much for the suggestions.

I am glad that you were able to prove my experience with measurements, as I had also done. Do the same with your RP 280 F once you´have received the new tweeters. You will be suprised what a simple improvement can achieve . And ...Happy New Year !

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After the tweeters arrived I tested the two speakers, the original and the modified, on the same channel (a / b on the amplifier) and I noticed that the modified cabinet lacked bass. If you live in an apartment building, your neighbors probably thank you, but I live in a single house, and I can't give up the earthquake effect. As I suspected, lining a bass-reflex enclosure with very sound-absorbing material reduces its performance, so I put the original material back. it was still an interesting and inexpensive experiment, and I'll use what's left to try and make some bass traps. Thanks a lot for experience. Bye!

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6 hours ago, Crab2k said:

After the tweeters arrived I tested the two speakers, the original and the modified, on the same channel (a / b on the amplifier) and I noticed that the modified cabinet lacked bass. If you live in an apartment building, your neighbors probably thank you, but I live in a single house, and I can't give up the earthquake effect. As I suspected, lining a bass-reflex enclosure with very sound-absorbing material reduces its performance, so I put the original material back. it was still an interesting and inexpensive experiment, and I'll use what's left to try and make some bass traps. Thanks a lot for experience. Bye!

Your first measurements have confirmed that the high-frequency/mid-frequency spectrum has been improved due to the insulation. That the mid-bass-mid-bass-upper bass-bass and sub-bass spectrum is now more cleanly staggered, is also not to question. If you now prefer resonances in the low pass instead of a clean staggering in the low pass and additionally still prefer room modes, then that is also okay. Futhermore, I don´t know which damping material was used , whether it was the one I used or something else. You never mentoned that.

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it is really difficult to understand which material to use. However the loudspeaker box is desaigned to match the bass reflex tube. Reducing the reflections of the case with the absorbent material also reduces the low frequencies, while optimizing the distortions. I have decided that, for my musical tastes, to keep the original configuration. A matter of taste, in the end the numeric tests optimize the performance, but it is our ear that makes the difference. Bass-reflex is very different of pneumatic suspension, where you fill the box with dump and no resonance is admitted. And, I think, the design of Klipsh is studied to have the best performance. Before buy it, I've carried on my amplifier to the phisical seller and tested it with more than 10 diffeent loudspeakers. Now, I've no time to make other experiments, probably, when I will retired from work, I will do it. 😉

Edited by Crab2k
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5 hours ago, Crab2k said:

it is really difficult to understand which material to use. However the loudspeaker box is desaigned to match the bass reflex tube. Reducing the reflections of the case with the absorbent material also reduces the low frequencies, while optimizing the distortions. I have decided that, for my musical tastes, to keep the original configuration. A matter of taste, in the end the numeric tests optimize the performance, but it is our ear that makes the difference. Bass-reflex is very different of pneumatic suspension, where you fill the box with dump and no resonance is admitted. And, I think, the design of Klipsh is studied to have the best performance. Before buy it, I've carried on my amplifier to the phisical seller and tested it with more than 10 diffeent loudspeakers. Now, I've no time to make other experiments, probably, when I will retired from work, I will do it. 😉

I see your point of view no problem really not, but you wrote .....where you fill the box with dump and no resonance is admitted

 

I think that´s the point , see how we have done that with  the rp 8000 , so you haven´t done the same with you rf 280`tees . I´m quite sure in this matter

 

481399427_ZuschnittDamping10.thumb.jpg.187b67374b0048480f585c39db24bfef.jpg

 

We cutted the new damping material in scale 1: 1 from the origin and have only covered the inside walls of the cabinet, the bass reflex ports have of course remained open . Best regards

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I badly explained myself. I cut the new damp like the original, plus I had covered the transverse inserts, and obviously left the bass reflex tube free. I had just given an example of the difference with pneumatic boxes. For the crossover I was unable to detach the old resistance due to the glue, and soldered the new one over the old. Bye.

box.jpg

new res.jpg

old res.jpg

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@Crab2k, thanx for your information, you did it like we did, but it´s still another damping material which is o,6 cm  thicker than the one we used. However well done so far. The resistors were really blown , never saw something similar before.

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  • 3 weeks later...

Hi MicroMara

 

Great posting on your RP8000 update. Looks like your cabinet updates delivered a noticeable improvement over the original.

 

Have just purchased a set of these speakers.  Although good as is I bought them with a view to updating to take them to another level.

 

And like you I intend to start with the cabinet then move onto the crossover.

 

I have seen the GR Research update but am not convinced that this guy always produces updates that actually sound better?  For example his conversion takes the tweeter circuit from a 4th order to a 1st order crossover with quite a low crossover frequency using a 6.2uF cap.  I'm not sure how good the tweeter will be at handing all that mid and LF energy with a 6db slope?

 

Also looking at his videos I get the impression that the effort he puts into his upgrades are just to flatten out the speaker response at 1 metre.  I don't get the impression he spends much time in auditioning the before and after results.  Well at least if he does that doesn't come across in his videos. 

 

So this leads me to your question.  How did you get on updating the crossover.  Did you keep as is just using better parts or did you do redesign maybe to take out the mid range notch.

 

Be great to hear how you finished the project

 

Cheers

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  • 3 weeks later...
On 2/2/2022 at 6:12 AM, OzBrit said:

Hi MicroMara

 

Great posting on your RP8000 update. Looks like your cabinet updates delivered a noticeable improvement over the original.

 

Have just purchased a set of these speakers.  Although good as is I bought them with a view to updating to take them to another level.

 

And like you I intend to start with the cabinet then move onto the crossover.

 

I have seen the GR Research update but am not convinced that this guy always produces updates that actually sound better?  For example his conversion takes the tweeter circuit from a 4th order to a 1st order crossover with quite a low crossover frequency using a 6.2uF cap.  I'm not sure how good the tweeter will be at handing all that mid and LF energy with a 6db slope?

 

Also looking at his videos I get the impression that the effort he puts into his upgrades are just to flatten out the speaker response at 1 metre.  I don't get the impression he spends much time in auditioning the before and after results.  Well at least if he does that doesn't come across in his videos. 

 

So this leads me to your question.  How did you get on updating the crossover.  Did you keep as is just using better parts or did you do redesign maybe to take out the mid range notch.

 

Be great to hear how you finished the project

 

Cheers

Just follow what we´ve gone so far ...Everything is well explained in the previouse pages. We ´re busy on the x-over works allready. We copy the board circuit values 1:1 but on higher level of coils, resisitors and caps. It may takes up to two weeks before we have finished the complete works. Not so much time righ now ....

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On 2/19/2022 at 4:48 PM, chips666 said:

Hello

Any mod progress?

How many sheets damping 10 did you use te cover both speaker insides

rgds

They´re 97cm x 47 cm . 3 sheets will be fine for the rp 8000 . Damping 10 is a product of intertechnik germany .

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Hello

 

could someone confirm that in RP8000 crossover

 

L1=0,29mH
L2=0,49mH
L3=1,34mH

Like in the picture page 1 ?

 

I upgrade crossover of my RP8000 and for inductors i would like to order Jantzen Cross Coil 16AW to replace them. I order components during the time i wait to receive speakers i ordered and will receive soon

 

For capacitors i ordered Claritycap CMR, Audyn Cap Plus and Paper Oil, Mills resistors and Audioquest Q2 + SILVER SPIRIT CuAg cables

 

Thank you in advance

 

Cordially

 

Pascal

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