Report On Upgrade From RF-5's to RF-7's:

[Doug C]

I had the RF-5's for about six months and really loved the sound with my little Decware Zen Select tube amp. Could not resist the upgrade bug to the RF-7's. Here are some initial impressions after having the RF-7's for about a week now.

Before removing the RF-5's I played a pink noise track and recorded the SPL at a given volume setting. Installed the RF-7's and played the same track at the same volume setting. SPL produced by the RF-7's was a tad over 2 dB higher. This is probably a reasonably good reference as to the increase in speaker effiency of the RF-7 over the RF-5.

During the first 3 days of continuous play I did not do any serious critical listening. Had the RF-7's placed in the same position as the previous RF-5's and had not changed my sub set-up (crossover setting or sub volume). Initially it seemed that the RF-7's did not have the midrange clarity or sound stage depth of the RF-5's.

About day 5 I got a chance to go through the complete sub set-up. Experimented with crossover settings, sub volume and setting up my parametric EQ in-line to the sub amp (EQ is in the low frequency path only). I found that the RF-7's had a good bit more bass output in the 50-100hz range compared to the RF-5's. The crossover setting of 80hz that worked well with the RF-5's just seemed to muddy things up with the RF-7's. I'm finding that a crossover setting of 50hz works much better with the 7's.

The RF-5's had been placed about 5 feet from the front wall to the front of the speaker. I repositioned the RF-7's so the distance from front wall to front of the speaker is about 4 feet. Also moved the speakers so that the total distance between them was increased by about 1 foot. This seemed to really improve midrange clarity. Will have to listen to the system for a few day with this set-up.

I guess the interesting point here is that an accurate A - B comparison of speakers is more complicated than just switching back and forth between speaker A and speaker B. Im my case ideal speaker locations for the two are not the same and ideal sub set-up is quite different.

One other note, as others have found, the foam insert visible through the rear ports was out of position on one of my speakers so that it was partially covering the ports. It was easy enough to get my hand through the port to tuck the foam up and above the upper 10 inch driver as positioned on the other speaker.

Doug C

[Deang]

Interesting post, especially your findings regarding sensitivity.

The RF7's should be considerably more dynamic. Is this not true?

[Doug C]

Hello Dean,

I thought the 2+ dB increase in output of the RF-7 over the RF-5 was pretty good considering the SPL was taken at the primary listening position which is approximately 10.5 feet from the speakers.

Dynamics of the RF-7 are top notch, a little better than the RF-5 in my listening room. I have to admit the RF-5 was a very good performer in my room, 11.5' wide, 21.5' long, 8.0' high, with two large openings into other parts of the home. Since I'm driving the RF-7 with only 2 watts/channel the slightly higher sensitivity gives my amp a bit more headroom. When playing loud (90-95 dB) the RF-7 produce the sensation of effortless sound. The RF-5 at these levels sounded great but maybe a hint of strain. Did not notice this until listening to the RF-7 for comparison.

Listening to the RF-7 placed in the same position as the RF-5 is dissapointing. The RF-7 had very little soundstage depth compared to the RF-5. Yesterday I moved the RF-7 out into the room a bit more (further away from the front wall) and increased the distance between the two speakers. This really opened up the soundstage (big increase in width and depth that matches the previous RF-5 set-up). With this arrangement the front outside of the RF-7 enclosure is only about 12 inches from the side wall so I'm using free standing absorption panels along each side wall to minimize the first side wall reflection and this is a noticable improvement as far as soundstage clarity. Distance between speaker centers is now approx. 8.5 feet, distance from speaker grill to primary listening position approx. 10.5 feet. Front of speakers are approx. 5.5 feet from the front wall and listening position approx. 5.5 feet from the rear wall.

With the new speaker positioning I'm gettig quite a bit more bass from the RF-7's (probably due to the speakers being closer to the side walls). Actually had to turn my sub off because things were a bit muddy. I plan on going back through the sub set-up today to get sub levels correct with the new speaker positions.

Once again I think the interesting point here is how differently the RF-7 and RF-5 interact within the same room. If someone were to demo the two in their home they can not assume that ideal placement would be the same for both. I read a review some time back where an individual opted for the RF-5 over the RF-7 because in their listening room the RF-7 had insufficeint bass output. I'm finding that if you have placement flexability the RF-7 have great bass output capability (even with a 2 watt amp). If you have limited placement options the RF-7 may be a tough animal? I'm fortunate that I have a dedicated room so there are few limitations to placement options.

Doug C

[mobile homeless]

Are you running your Zen amp from the volume pot on the rear of the amp or your B&K preamp? I have noticed several things running various SET systems. I have always been a propoent of a passive preamp/attenuator in the past having owned various models since the early 80s. Actually, I have always had at least one Passive preamp in house over the last 20 years, just changing types and models. I find it offers a valid option and the most transparency for the least amount of money. Most line stages tend to muck up the signal more than anything and the passive, if used under the right conditions, was a nifty little option. You have to have a CD player or source with a good power supply and enough volts output. You also have to have as short a pair of quality interconnects as possible to keep attenuation of the top end out of the equation. And the amp(s) have to have a high enough sensitivity rating.

All the above being met, I finally came to the conclusion that SET amps, no matter the quality, really benefit from a quality active TUBE LINE STAGE over the passive approach. In general, I have not found any of the solid state preamps to perform up to my liking preferring the passive to this approach. The solid state line stage just imparts an electronic cast to the presentation, not matter the quality, although better examples tend to be more subtle. Still, I almost ruled out all solid state active stages even though I had some fine examples pass through. Indeed, I once had the B&K Pro 10MC and the Sonata for a brief stint. The Pro 10MC did have a supposed passive switch which was much better than the active stage but not up to dedicated passive devices. I have had Klyne, SUMO, Krell, B&K, ADCOM, PS Audio, Superphon options among others. In all instances, when compared to a quality tube preamp, the solid state models sounded less natural and more flat, regardless of cost.

But back to my first point, the quality active tube preamp really fleshes out the midrange adding some needed drive and warmth to the SET presentation. The dyanmics are noticably improved and there seems to almost alway be increased pass. Of the preamps, I have found the 6SN7/6SL7 option to offer the clearest glimpse into the music while offering nice bloom, dynamics, and resolution, depending on output tube. I still have a Creek OBH-12 passive but rarely use it in my 2A3 monoblock/Cornwall main system.

Although the B&K is a nice piece of gear, I believe you will, however, achieve a noticable increase in performance moving to a GOOD active tube preamp over passive, active solid state, and/or a volume control on amp or CD player, the last being the least quality.

kh

[leok]

Doug,

What kind of music do you listen to? Are you comfortable with the general voicing of the RF-7s?

My RF-7s are about 10' apart, 8" from the back wall and 1.5' from the side walls (except there is no right side wall, it is a pasage-way .. so no corner affect on the right side).

I have found the RF-7s to be tricky, but they have a high end clarity that I suspect cannot be achieved with the legacy 3-way approach. In the classical (chamber to full orchestra) music I generally listen to, the high end definition produces accurate violins, harpsichords, woodwind harmonics, and recording space ambience. My Forte-IIs provide a more natural punch in the lower midrange, which I miss in the RF-7s. With vocals, the RF-7s are totally unforgiving with sibilances (s, t, sh, ch, etc), but with the right amplification, I can get a more natural sound with the RF-7s). The Fortes produce a more natural human voice with scrambled sibilance and upper harmodics. It's not an easy choice.

I have not tried quality SET amplification and am building a pair of Mooddogs now. Maybe my impressions will change with the Moondog as ther reference amp.

leok

[Deang]

"...violins, harpsichords, woodwind..."

Leo, are the musical instruments of sorts, or something else altogether?

I think that problem with silibance will substantially decrease with the Moondoggies.

Doug, a very nice description of your setup. A couple of things here when comparing the 5's and 7's. They are really very different speakers, especially when bringing in room acoustics. The 7's weigh 30 lbs more each, are 3.5 inches taller, almost 3 inches wider, and 2.5 inches deeper. It doesn't sound like much, but when you factor in the additional mass, and the additional total surface area (which adds up) -- it's not surprising they would sound so different sitting in the same spot.

I have mine 23 inches from the side walls, and 34 from the front wall to the rear of the speakers. They are 7 feet apart (center of cone - to center of cone), and I sit a little over 8 feet back. One thing I did, was make sure the distance from the side walls, and the distance from the front wall -- were not multiples of each other.

[leok]

Dean,

I meant to say that the RF-7s, with my best amplification, will reproduce the most natural sibilances (the unvoiced noises we make when we speak). But those sounds do have flaws. With the Fortes, the sibilances are smoother, but much further from accurate. I suspect this is evidence of the RF-7's advantage and risk in those upper frequencies.

I am guessing the Moondogs will show that some of the flaws are in my amplification and sources.

leo

[Doug C]

Thanks to everyone for their input on this subject. Have been listening and experimenting some over the past two days and will try to answer some of the questions.

For evaluation purposes I have been using the Chesky Records "Guide to Critical Listening" CD. This CD has about 14 tracks that include Rebecca Pidgeon, Sara K., Leny Andrade, Livingston Taylor, Ana Caram, etc. I generally listen to Rock and Blues but find this CD very useful for evaluating the effect of system changes. Each track has been selected for it's specific qualities, Soundstage Depth, Midrange Purity, Transparency, Rythm & Pace, etc. I purchased this from Audio Advisor a few years back.

I had been listening with my Marantz CD-17 CD player connected via interconnects to the B&K Reference 30 preamp, using the B&K Direct Pass Through via interconnects to the front Direct Inputs on the Zen Select (the Direct Inputs bypass the Zen volume pot). This arrangement allowed me to use the Zen for 2-channel play and HT without physically switching any cables.

Based on input from Mobile Homeless I decided to backtrack and connected my CD player via interconnects directly to the Zen Direct Inputs and from the Zen directly to the RF-7's (B&K preamp removed from signal path). The real differences are a much greater sense of the recording space (you can hear the effect of the recording studio) and greater resolution of fine vocal and instrument detail which add to realism. Now the difference in music reproduction quality is not night & day, but at the same time once you hear these things you don't want to do without them either (if that makes any sense). So as Mobile Homeless stated, the preamp tends to muck things up a bit.

Male and Female vocals are very natural with no apparent chestiness from male vocals. On well recorded material you can clearly hear vocalists inhaling. Eliminating the preamp also seems to have improved soundstage depth. Vocals and instruments seem to be more distinctly placed within space. The preamp seems to impart a thin veil that tends to mask that last little bit of detail and clarity.

Doug C

[prodj101]

on paper the mid range on the RF-5's should be clearer though right? smaller drivers have an easier time moving fast, and to play many midrange sounds, they have to move fast.

[Doug C]

The RF-5 is a great speaker. Comparing the RF-5 to the RF-7 the RF-7 performs as well if not better than the RF-5 in the midrange based on my listening. I was a skeptic but hearing is beliving.

Now I have to say after listening to the RF-5 & 7 at two different dealers I was not impressed (on music). In each case speaker placement was bad and the systems were really set-up for HT demos (subs turned up to much for music). I took my CD player and amp in for a listen. Moved the speakers out into the room, played music with my gear and no sub. Much different impression.

Doug C

[mobile homeless]

Doug, you correctly identified what happens when you remove an average to above average preamp from the chain. If using short interconnects, with a good output stage/enough volts output in the CDP and a sensitive enough amplifier, a passive can:

1. Improve resolution

2. Increase sense of air around instruments

3. Hear better into the soundstage with more space

4. Increase of soundstage depth and width

5. Much lower NOISE FLOOR depending on your pre

All of the above is GREAT and present some amazing changes on first listen. Unfortunately, the drawback is a slightly more thin sound to the midrange with a bit of the dynamic drive missing ever so sligtly. And with SET, you lose a bit of midrange warmth as well.

That is why the ultimate to me is a GREAT tube preamp with quality NOS tubes. I fleshes out the midrange and still provided great clarity and excellent soundstage information. It's nice to have both but I find myself with the good tube active stage most of the time. Still, when you throw in that passive pre, it can be a fun trip.

I have not heard a really good solid state preamp in a LONG LONG time.

kh

[-klipsch]

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[mobile homeless]

Contrary to that, I find the Joe Blow customer to be very taken with Klipsch, at least from what I have seen. Actually, it is the Joe Blow customer looking for "sparkling highs and gobs of deep, chest pounding bass" for his or her Home Theater system that has both kept audio stores alive and propagated some of the most poor sounding speakers judged on musical merits.

You have had better luck than I with the 6550. I have never heard a modern 6550 amp that could really be called sweet although the Svetlana is sure better than a host of other 6550 modern tubes. The 6550 is my least favorite output by and large. Mention should be given to the little EL-84/6BQ5 as it is one of the best sounding tubes around when in a good circuit w/ good iron. I used to shun this tube except in guitar amps. Now I rank it right up there.

kh

ps-I generally prefer the better Mullard long plates to the Telefunken as well. Both have good points. Telefunken last until cows come home and head back to pasture...

[-klipsch]

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[prodj101]

they have a klipsch theatre set up at a place near me, and it is really nice. they have the RF-7's, RS7's, RC-7, and RSW-15, with the top of the line denon receiver and dvd player. than, a sony front projection screen.