You are reading the older HTML site
Positive Feedback ISSUE 67
REV 7 Loudspeakers
as reviewed by Mike Wechsberg
John "Fritz" Heiler (he doesn't mind just being called "Fritz") has been building speakers since his high school days more than 30 years ago. I'm sure many of you have encountered Fritz Speakers at shows, especially if you live in the Southern California area. I've always found his speakers to have a very natural and musical sound, reflecting his background as a musician, and I've always been impressed by his deep knowledge of drivers, crossovers, and speaker design when I've chatted with him. Recently, his Carbon 7 speaker has gotten favorable reviews in several magazines, and has become his best seller (see Kent Johnson's PFO review of the Carbon 7 here in Issue 50). Fritz has a pretty broad speaker line for such a small manufacturer, and he is constantly experimenting with different drivers. I mentioned an interest in reviewing one of his designs if he came up with a cool new driver configuration. That is how the REV 7 came to me.
The REV 7 is a two-way stand-mounted speaker with a rear port in a rectangular enclosure measuring 16"H x 9"W x 12"D and weighing 30 lbs. each. In looking through the Fritz Speaker web site, you can see that Fritz is partial to these basic MDF rectangular boxes for his speakers. Fritz told me he has experimented with more elaborate boxes, including high-density materials and sand-filled designs, but has gotten the most consistent results with the basic rectangular box with good internal bracing. In addition to his classical music background, Fritz has also worked as a cabinetmaker for many years, so his speaker boxes are beautifully made. He offers several standard finishes including cherry, walnut, maple, mahogany, and oak, but he also offers custom finishes as well. Give him a call for options and pricing. My pair was finished on all six sides in a hand-rubbed walnut finish. Magnetically-attached grilles are usually supplied, but my pair came without grilles.
The REV 7 has a nominal 4-ohm impedance and works with amplifiers rated from 30 to 150-W rms. The specified frequency response is 37Hz – 20kHz +/- 3dB with a sensitivity of 89dB referenced to 1W @ 1M. That's quite an impressive low-end reach for such a small and reasonably priced speaker if true, and I think it is. This performance is due to the truly outstanding drivers in the REV 7. The mid/bass unit is a ScanSpeak "Revelator" 7-inch that gives the speaker its name. This has a paper cone with distinctive slits that reduce resonances. Other features of the design also minimize resonances and allow for long excursions for low frequency extension and high sound pressure capability. This driver has been around for a few years, and has found itself in a number of high-end speakers costing $10,000 or more, including YG Acoustics, Wilson Audio, and GamuT. It's hard to find the Revelator 7 in any other commercially-available speakers under $4000, except for some DIY designs. The Revelator 7-inch is mated to a 1-inch AirCirc tweeter also from ScanSpeak. This has a textile dome and a unique magnet structure. According to ScanSpeak, the AirCirc Magnet system is "named for the way it optimizes air flow within the chamber—rearranges the traditional magnet structure from a single magnet to an open magnetic circuit comprised of six separate neodymium slugs. This, in combination with the chamber, results in the elimination of the reflections and resonances that compromise the performance of traditional motors." This tweeter is also found in some quite expensive speakers. Fritz Speakers packages these very high performance drivers into an assembled speaker system at an accessible price of $2500 per pair.
Fritz uses a very simple series crossover containing only four components. The crossover frequency is at about 2200Hz. The drivers must each have a much extended response on either side of the crossover frequency to make this work. I think the simple crossover contributes to the easy musical flow I heard from these speakers because there are not many electrical crossover components to muck up the sound. Plus the smooth phase behavior of the series crossover allows the speakers to image wonderfully. Other speakers using one or the other of the REV 7's drivers employ very complicated crossover filters with a large number of costly components. This approach can also work, but is much more expensive to implement.
Fritz told me the REV 7s I received had some hours on them, but could still use some break-in. I was concerned they would strain in my large listening room if I substituted them for my reference floor-standers, so I decided to set them up in a smaller footprint within my room. I set the speakers on some 30-inch stands well out into the room, about 6 feet apart pointed straight ahead, and I moved my listening seat about 7 feet from the speakers. The amplifier I used was the Maker Audio G9 solid-state amp, in for review. The Maker amp is derived from the design of one of the amplifiers from EDGE Electronics that many of you may be familiar with. It puts out 225W into 8 ohms. I had been listening to the Maker amp for a few weeks in developing my PFO review and was much impressed. I used Harmonic Technology Pro-9 Reference speaker cables that cost more than the speakers. Other items included the E.A.R. 868 preamp and E.A.R. Acute 3 CD player (both tube designs), and the Townshend Rock 7 turntable with the London Reference cartridge. After breaking in the speakers for 20 – 30 hours and then listening a few days to the Maker amp, I switched to the E.A.R. 890 amp to see how the REV 7s would do driven by a tube amplifier.
Fritz told me the speakers like 24-inch tall stands, but the stands I had on hand were 30-inches high. Even though this put the tweeter within an inch of the height of the tweeter in my Marten Djangos, the resulting sound for the REV 7s was lacking in sparkle and air and seemed a bit dark. I ended up using a taller chair with a cushion under my butt, that put the tweeter about at ear level. I also experimented with toe in. I started with the speakers pointed straight ahead. This gave me too much box sound and the imaging was a bit vague. After adjusting the speakers to point directly at me I heard pretty good detail in the highs and a flatter frequency balance, but I still didn't like the imaging. It was too narrow with not enough depth. I tried three or four more adjustments and found the best compromise with the speakers toed in slightly so they crossed about a foot and a half behind me. This seemed to provide the most uniform response with a broad soundstage and layered depth.
One other adjustment was the spacing from the rear wall. I initially had the speakers about 5 feet out into the room and used this position while the speakers were breaking in. However, I was curious if the REV 7s could produce more bass, so I started moving the speakers closer to the rear wall, with the expected effect of bringing up the bass. I settled with the speakers about 3 and a half feet out into the room and slightly further apart (to about 7 feet). In this position I heard an impressively strong and extended bass response on recordings containing good low frequency content, and a pretty flat overall response over the entire audible range.
I should mention one other setup item. A number of my audiophile friends swear by the use of Stein Speaker Matches to improve both the low frequency response and lower midrange of many speakers. These were reviewed in PFO by Bob Levi last year in Issue 61 and I have also become a believer in this relatively inexpensive tweak. Stein Music now has an improved version of the Speaker Matches available at a substantially higher price, but I only have the original version. I was amazed at the improvement these made on the REV 7s, tightening up the bass, making it more dynamic, and adding an apparent half-octave extension. It also seemed to help add clarity at higher frequencies as well. I happened upon a discussion on the Internet that noted one disadvantage of a series crossover is it does not do as good a job as a more common parallel crossover in preventing back EMF from the woofer getting into the tweeter. I don't know if this is true (it has to be true if it's on the Internet, right?), but this might explain why the Stein Speaker Match helps this speaker significantly. Anyway, if you choose to try out the REV 7s, I strongly suggest you get the Stein devices as well. They will give you a worthy reward. I chose to keep the Speaker Matches in place while I reviewed the speakers.
Let me get right to the point and tell you this is a great pair of speakers characterized by a smooth, clean, coherent sound with lots of energy and pace. They just allow the music to flow out of them and ease instruments and voices into the room. I could not get these things to make an ugly sound, at least not on the music that I play. Nothing screechy, bloated, hazy, or slow. The high end is smooth and sweet with wonderful clarity. They are not especially analytical or super transparent, but they let you hear just about everything you need to get the message and emotion out of the music. The highs had more delicacy and air when I used my E.A.R. tube amp instead of the solid-state amp, but I don't think many users will want to use these speakers with such an expensive amp. On the other hand, if you've got a superior amp, the speakers will make it worthwhile.
The midrange is sweet if a little on the warm side, at least with the electronics and cables I was using. I noticed the articulation of lyrics was especially good on both male and female voices. I play lots of vocals when I evaluate speakers, and I feel the REV 7s portray voices accurately, if not with the "in the room" illusion one gets with much more expensive designs. I also played quite a bit of piano on this pair. For example, I rolled out an old VAI Audio CD of Ivan Moravec playing Chopin. This disc is a re-issue of an older Connoisseur Society record from the 1960s, and the piano tone through the REV 7s is just right over the full range. I also listened carefully to Duke Ellington's piano in the IMPEX Records LP reissue of Ellington Indigos and was most impressed.
The bass on the REV 7s goes amazingly low for such a small speaker. I measured flat bass down to 40Hz using my Radio Shack sound level meter, with significant output remaining at 32Hz. This is enough low-end for 95% of recordings. Credit must be given to the Revelator 7" driver with its long excursion and strong magnet assembly. Quality of the bass was excellent, firm, fast, tuneful, and free of overhang. This was true in pop vocal recordings with strong bass like Holly Cole on Don't Smoke in Bed on the Manhattan CD edition, and Jennifer Warnes on the IMPEX LP reissue of The Hunter. I also found myself listening to quite a bit of classical music on the REV 7s because the speakers had such a superb low end with plenty of hall sound. Examples include the Reference Recordings QRP LP of The Firebird Suite with the Minnesota Orchestra conducted by Eiji Oue, and Debussy's Iberia on the XRCD reissue of the RCA Living Stereo recording of the Chicago Symphony conducted by another Fritz, Fritz Reiner. I listened to the latter two recordings with the EAR tube amp and, in addition to the convincing bass, noted the exceptionally well-rendered imaging that was very wide, deep, and filled out to the rear edges of the soundstage. Small two-way speakers like the REV 7s are known to image well because of their simple design and close proximity of the two drivers. Certainly this pair will not disappoint in this regard, but I think their performance is above average because of the simple crossover network they use and the quality of the drivers.
The dynamic capability of the speaker was also exemplary. They sound very clear and distinct at low levels, yet can really pound out the music at high levels. Dynamic contrasts are startling (at least on a few recordings), and the transient response is very good. I did hear some strain at very high levels and the image flattened somewhat, but this was when I was really pushing them in my large room. It's unlikely you will get to this at sane levels in a small or medium size room better suited to these speakers. The speaker is better at macrodynamics that it is at microdynamics, but that is to be expected in this price range.
I also want to emphasize again the "flow" of the music as played through the REV 7s. On some speakers it seems like the music just never gets out of the box, but that is not true of these speakers. On upbeat material it is very easy to follow the line, and the music is hard to ignore. The same characteristics give even slow music considerable drama and emotion.
So, the Fritz REV 7s check just about all the boxes in what most audiophiles and music lovers are looking for when they want a small 2-way loudspeaker: smooth full range frequency response, clarity, dynamics, coherency, flow, imaging, transparency, etc. They need good stands to sound their best, and benefit from the use of fine electronics, cables, and some tweaks. They cost $2500, Internet direct, with a 30-day money back trial period. The $2000 - $3000 price range is a very competitive one with many fine speakers, some from well-known national brands carried by audio retailers around the country. I haven't heard enough of these to give you useful comparisons, but the REV 7s rank right on up with the best of them I have heard. In addition, they are made virtually by hand in the USA by a hard-working music lover, and they use high-quality drivers from Europe, not some cheap derivatives. I can also say after spending several weeks with the REV 7s playing in my home reference system that they play all kinds of music clearly, faithfully, and enjoyably and they sound better to me than many name brand speakers at the same or higher price. I think most people will find them very easy to listen to so I would strongly encourage you to visit the Fritz Speaker web site and arrange an audition. Mike Wechsberg
REV 7 Speakers