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How to get more midrange out of my RF7s


m00n

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Hey all... I am turning the pros here... I was Lord of the Rings 2 Towers last night. And to cut right to the chase, I noticed the there seemed to be great detail and hi's but the soundtrack really seemed to be missing that nice full midrange. I was wondering what can I do to help bring out more mids? Could it be as simple as speaker placement or will it require more drastic measures such as crossover upgrades in my 7's?

Thanks all.

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Unless you hear the same thing on all discs, than I would have to say that maybe that was the way the disc was recorded. You know what I mean, if that's the only problem, than I wouldn't get too worked up. Some people will tell you all sorts of cure-alls like using a green marker on the edge of your discs, and silver wire, magic stones on which to set your amp, blah blah, blah. Your mileage may vary with each " upgrade " but I think that you have a well setup system already.

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Right now it looks like you have zero room treatment. My guess is that when you get something on those walls to take the bite out, you'll be able to crank the mid more. Does that make sense? Your probably getting a lot of HF reflections making the room seem bright. Also do you have them set to large or small? The small setting might give you a shade more detail in the mid. What interconnects do you have? I dunno but I'd start with these type things before I started screwing with a crossover but thats just me.

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Missing lower midrange power (good esp for piano, cello, probably voice too) was my main reason for obtaining the Chorus-II (classic 3-way approach). I find with the RF-7, if I sit, 3' to 6' from them, with the speakers directly facing me and my ears in line with the upper cone, I get maximum mid presence.

I think the cones really can't keep up with the dynamics of the horn, but there is a sweet spot, within 8' from the speakers, where the cones do pretty well.

Most people don't notice the crossover problem that I complain about with 3-way systems. What I like about the RF-7s is there is a single driver from 2KHz up. With some music, that clean top end is worth the loss in lower mid punch. If I want room filling, dynamically balanced sound I use the Chorus-II.

leok

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Jolly Roger

Yes you are correct, I don't a have a lick of sound treatment in the room other than the seats and carpet. I had the same thoughts as you on this. I hope it does help when I get a chance to start putting teatments on the walls...

Oh and Mike, thanks for bring out old fiascos. 2.gif

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My pleasure!2.gif

I tend to agree with Micheal Hurd, If it was just the one particular DVD that gave you the (Lack?) of midrange, than more than likely it's just the way the audio was recorded on the DVD.

Maybe they spent so much time with emphasis on the lower bass, and the higher frequency registers, that they kinda forgot about the dialog. Voices are the major part of the midrange.

Have other DVD's given you the same problem?

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If I sit 3' to 6' from themmy ears in line with the upper cone

With all due respect Leo, but if this is the best the RF-7s are doing for you, you might consider selling them. If I had to sit less than 6 feet away from a set of speakers to sense I was hearing the full spectrum of sound they would be gone.

Mine are 12 feet apart, center cone to center cone and I sit 12 feet back. I have never felt the speakers were lacking in lower midrange punch. The Snare Drum in Rock Music has great presence, and the way in which it is reproduced tells me the integration between the top and bottom is about as good as Ive ever heard from a two-way. The fundamental frequency of the Snare sits in the 150-250 Hz range, and the snap resides at 5Khz. It Sounds perfect.

I think the cones really can't keep up with the dynamics of the horn

Maybe your amps lack the ability to adequately control the cones. With no feedback, there is very low damping, and the cleanest most accurate midrange will be obtained when the cones are under good control. I believe the RF-7 greatly benefits from a little bit of feedback and the increased damping the feedback provides.

From an obscure website I saved the following:

The use of global negative feedback does several things: it flattens and extends the frequency response, it reduces distortion generated in the stages encompassed by the feedback loop, and it reduces the effective output impedance of the amplifier, which increases the damping factor. All of these things affect the tone in some manner.

The flattened, extended frequency response obviously changes the tonal character by removing "humps" in the output stage response and producing more high and low end frequencies.

The distortion reduction makes the amp sound cleaner and more "hi-fi", up to the point of clipping, with less output-stage generated noise.

Perhaps the main difference for the "feel" in a negative feedback amplifier, as opposed to a non-negative feedback amplifier, is the increased damping factor produced by the negative feedback loop.

"The decreased effective output impedance causes the amp to react less to the speakers. A speaker impedance curve is far from flat; it rises very high at the resonant frequency, then falls to the nominal impedance around 1kHz, and again rises as the frequency increases. This changing "reactive" load causes the amp output level to change with frequency and changes in speaker impedance (a dynamic thing that changes as the speakers are driven harder). Global negative feedback generally reduces this greatly. This can be good or bad, depending upon what you are looking for. Negative feedback makes the amp sound "tighter", particularly in the low end, where the speaker resonant hump has the most effect on amplifier output.

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Rick,

I just spent the last 15 minutes checking out your site. Dude, you got some serious work into that -- nice job!

I think the setup is great. Hard to improve on the RF-7 setup in front of the screen. Looks good. I'm with some of the others here, and I think it was just the way the DVD was recorded.

Just two things:

Remember when you had the subs stacked on top of each other? That was actually better. The way you have them now looks nice, but it's not the optimum way of doing it. Get them stacked up again and pick a corner. You'll get smoother response, and won't have to worry about phasing issues. Also, you will generate more bass with less power -- always a good thing.

You are still going to have to break down one day and get yourself a 100 LB. amp to run the front three.9.gif

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Dean,

Speaker impedance has no impact on frequency response of pwm, except for the top octave (where RF-7, Forte, and Chorus are all reasonably behaved anyway), and I have the same impressions with that amp. I like the RF-7s. I prefer them at times, like I said, and that's why I keep them. No speaker is perfect.

I bring up the way I listen to them in order to illustrate the point(s) I am making. I'm not suggesting everyone has to listen that way.

m00n,

I had forgotten that you have past experience with 3-ways. With that in mind, it may just be the particular DVD.

leok

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