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Johnny's Jill

RF-7 upgrades

37 posts in this topic

I asked gothover to come over today to upgrade my RF-7 (deans crossover mod) and dynamat the horns.

We did one at a time, used dayton capacitors, and mills resistors.

A/B comparison was really night and day, some tracks that were previously unlistenable, are now nicely detailed no longer harsh and bright.

This is not the first time I have heard this mod, though it is the first time I could a/b them side by side.

Dave thanks for taking time out of your day to straighten out my 7's.

Dean, nice crossover upgrade.

Craig 73

Edited by Johnny 5

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Dave thanks for taking time out of your day to straighten out my 7's.

Its all good.

Dean, nice crossover upgrade.

I agree, this is a worthy mod. I would not own a pair of RF-7's without them.

Dave

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If it is the same crossover Dean made for me back when I owned 7's, it is indeed an upgrade.

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I wonder what made the biggest difference, the xo or the Dynamat?

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I think both are contributing to the improved sound.

The dampening of the horns has minimal effect at low volume, and I believe the low level clarity has improved as well.

Modifying the crossover consists of a resistor change and replacement of the capacitors.

All in all, I believe this is a good mod, well worth the effort.

Dave

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If it is the same crossover Dean made for me back when I owned 7's, it is indeed an upgrade.

I believe it is, though as I recall Dean used premium capacitors in his mods.

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I seen the video on the Dynamat mod. It looks relatively easy.

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I think it's awesome that people are still doing this mod.

I wish I could find the thread where I told Leo that he was "out of his mind" for doing that to his new loudspeakers. He told me not to be critical of something I hadn't tried. I expected to hear no improvement whatsoever. Instead, it launched a business.

I did the horn dampening mod on my RF-7s and heard no difference.

C'mon guys and gals, it's a composite resin designed NOT to resonate - it would be like putting that stuff on a K-401. Once you screw it to the motorboard it's completely inert. That cabinet is well designed, and very rigid, and I believe the motorboard is a full inch thick.

Did you Dynamat first and listen for a while, or do any type of comparison with a Dynamatted version to stock - or did you guys do everything all at once?

Derrick, if you did the horn, and did nothing to the network, how do you think that would compare to doing the network, but doing nothing to the horn? I read the question and initially thought you were joking.

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My point was two variable were changed and that make the difference hard to separate. When experimenting it is better to only alter one variable and measure or some other method to compare X and X'. :)

Edited by derrickdj1
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Ah, I see. Yes, I agree. Really though, the Dynamat does little if anything. The network upgrade has a long and well established track record, it's not what I would call "a subtle improvement" - it's pretty dramatic.

Leo eventually rebuilt both crossovers using Jensen paper in oil capacitors. I thought he was crazy for doing that too. : )

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Did you Dynamat first and listen for a while, or do any type of comparison with a Dynamatted version to stock - or did you guys do everything all at once?

Really never intended to do the Dynamat, but the tweeter needed to be removed to do the crossover mod so I did it as well.

Dynamat does little if anything.

Agree, but like many other mods, it doesn't hurt.

Dave

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Ah, I see. Yes, I agree. Really though, the Dynamat does little if anything.

I dont know about that Dean. The un-dampened hf horn sounds like an empty dixie cup when you tap on it without dampening. With the dampening applied, sounds much more solid.

btw, I do mean installed in the box.

Also found some other issues while doing the crossover mod. I noticed the shielding on the back of the HF driver had come loose, at 2 of the 3 glue joints. Quick easy repair, just something to look for if ever the drivers come out for service.

Craig

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That's true, if you flick or tap on one it makes noise, but that doesn't mean it resonates while producing high frequencies - that horn isn't even playing any midrange. Like Dave said though, it's inexpensive and easy to do, and it doesn't hurt anything.

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I went back and modified the other RF-7 yesterday, once again verified positive results.

I took a good look at the tweeter lens, and though still not sure if it does resonate, it sure is thin, and susceptible to vibration.

Although the HF doesn't do a lot of mid work, I suspect back pressure from the shared air space could actually cause the HF lens to flex and resonate, unlike the K-401 which is not located in shared air space.

This is purely speculation, but I do feel it at least merits attention.

Dean G, you have told me several times, "All those 1% improvements all add up". You're right.

Dave

Edited by GotHover

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Good post.

I've changed my mind -- I can't complain about one type of horn of not being rigid enough and prone to resonanating, and then give a pass on a flimsy unit like the RF-7 horn. I'm going to start advising that people consider doing this while they have the horns out.

Where do you find this stuff Dave?

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The largest improvement comes from the added resistor, without a question.

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Is dean's upgrade something fairly easy to install by yourself? I would really like his upgrade, but know shipping alone would sink it for me. I would definitely be down for buying the crossover mod, and then taking it to someone nearby (lincoln ne) that knows what they are doing. Is there truly that big a difference in the listening quality?

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Shipping is the cheapest part of the upgrade.

If you even have the slightest mechanical aptitude, the swap can be done. Worst case scenario, start a thread and we'll answer your questions.

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How much is a pair of deans crossovers?

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How much is a pair of deans crossovers?

Your answer is an e-mail away.\

dgwescott@gmail.com

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