Revel F206 Technical Problem Verification

[home_theatre_man]

Interesting theory crafting question for the forum...

My father has had a pair of Revel F206s for a number of years. He has never been entirely happy with them, which has always kind of surprised me because of Revel's standing and the fact that he is not usually particularly critical of sound quality. Frankly, I didn't pay much attention until recently, when he apparently got annoyed enough with them to decide to replace them and asked me to help him find something else.

When I shopped the idea around to my industry contacts (including Revel competitors), they mostly had the same reaction I did - surprise. Especially when we got to discussing the specifics. Someone finally floated the idea that one of his F206s is actually...broken. There is some interesting evidence for this theory:

-- He uses Audyssey to correct his system. Audyssey intermittently flags one of the F206s (always the same one) as polarity reverse. It's done this with the speakers in more than one room and multiple positions in those rooms. I popped them for him with my Gold Line APT2, and all the drivers in both units register (+) for (+) voltage on the red terminal.

-- Audyssey consistently goes to work boosting the treble (tweeter range) in that same unit, while it leaves the treble in the other unit almost entirely alone. Again, he showed me his Audyssey results, and it flips sides when he swaps speakers, and this tracks consistently through different rooms.

-- One of his chief complaints is poor imaging, and he's right; based on my quick listen they don't. Definitely not in the same league as my M105s. He complains of having to stack sofa cushions to raise his head or move forward and backward to acquire the center image. I've never heard the F206 anywhere else, so I don't have a reference point for how they're supposed to image.

-- When you listen to narrowband noise bypassing EQ (the AVR internal noise), the speaker that throws the polarity error sounds slightly "hollow" compared to the other one. It's not something I would call out if there weren't other evidence. Comparing to external noise through the EQ, that speaker does sound a bit more forward - but remember the EQ boosts its treble.

-- He's got the F206 in a surround system now with other Performa3 models, and the speaker in question is the oddball in terms of timbre. I just gave a quick listen to cycling narrowband noise, and it's definitely a "one of these is not like the others" scenario. It doesn't smack me over the head as being a broken speaker, but considering the other evidence...

Other diagnostics I ran spur of the moment were to listen to swept tone at various levels, which revealed no audible distortion, rub, or buzz in any of the drivers. In fact, it was one of the cleanest results I've ever heard.

I can haul my analyzer over there and look at it. I thought before I did that, I would take a quick survey here and collect theories about what to look at. I have my own ideas, but speaker diagnostics isn't my specialty. When I find a speaker in the field that I suspect is broken, I just kick it back to the company and have them take a look at it or replace it. But those are all under warranty. This one is long out of warranty.

 

[astr0b0y]

Does it still sound broken with Audyssey bypassed?

 

[home_theatre_man]

Does it still sound broken with Audyssey bypassed?

I would say that it sounds more "broken" with the EQ bypassed.

 

[Beave]

Pull the two F206s out, put them side-by-side, and play pink noise into one, then the other. They should sound nearly identical. If not, one is broken.

If they don't sound the same, next do a tone sweep (not too loud!), and see at what region they differ the most. Post that info for us here.

Edit: And do all of that with Audyssey and any EQ turned OFF.

 

[home_theatre_man]

Pull the two F206s out, put them side-by-side, and play pink noise into one, then the other. They should sound nearly identical. If not, one is broken.

If they don't sound the same, next do a tone sweep (not too loud!), and see at what region they differ the most. Post that info for us here.

Edit: And do all of that with Audyssey and any EQ turned OFF.

I finally made it back over there with enough time to move the speakers. There is no audible difference in pink noise with the speakers side-by-side, except what one would expect given the slight difference in top octave as measured by Audyssey (see OP).

The single tone 20-20 kHz sweep is one of the cleanest and most uniform I have heard from a pair of speakers.

Nothing here indicates anything is wrong.

 

[AdamG]

Figure out what channel (Left or Right) seems to not be imagining properly. Looking for weak speaker. Once identified swap speaker locations and repeat test. If problem moves with speaker. You have a speaker problem. If imagining problem remains in the same location (L or R) you have an Amp/AVR problem, wiring problem or room acoustic problem. Just a suggestion to narrow down the trouble shooting. Good luck.

 

[McFly]

I recon the tweeters inverted on one of them

 

[home_theatre_man]

Figure out what channel (Left or Right) seems to not be imagining properly. Looking for weak speaker. Once identified swap speaker locations and repeat test. If problem moves with speaker. You have a speaker problem. If imagining problem remains in the same location (L or R) you have an Amp/AVR problem, wiring problem or room acoustic problem. Just a suggestion to narrow down the trouble shooting. Good luck.

Using test stimulus of gated 500 Hz - 2 kHz narrowband pink noise, the phantom between the two F206s seems to "spread" or "widen" from the midpoint out toward each speaker as the frequency increases.

Another way to put it is that the octave (approximately) from 500 Hz to 1 kHz sounds "in-phase" (solidly centered at the midpoint) while the octave (again, approximately) 1 to 2 kHz sounds "out-of-phase" (emanating from each speaker individually or outside the speakers). It may be a much narrower band than one octave; it's hard to tell.

He has the C205 and M105 set up as center and surround. The half-left and half-right phantoms also exhibit this "spreading" effect. The M105 polarity must be reversed to produce phantom side. This in and of itself is not terribly unusual; however, it is worth noting given the other symptoms.

 

[home_theatre_man]

I recon the tweeters inverted on one of them

I tested all drivers using the Gold Line APT2, and they all report forward motion for (+) voltage applied to the red terminal.

 

[Blumlein 88]

Play pink noise on them and record it. Even if all you have is a phone to record with. Most of those aren't too shabby above 200 hz. And you are looking for differences between them, so the microphone doesn't have to be dead flat itself. Or if you have other mics and the means to record.

 

[home_theatre_man]

Play pink noise on them and record it. Even if all you have is a phone to record with. Most of those aren't too shabby above 200 hz. And you are looking for differences between them, so the microphone doesn't have to be dead flat itself. Or if you have other mics and the means to record.

I will eventually use REW. My time in front of the system is limited, so I have to prioritize what to do.

And note from the OP that the idea one of the F206s is "broken" came from someone else. I have personally seen or heard nothing to suggest an abnormality beyond typical manufacturing tolerances.

To say that the F206 pair doesn't image is an exaggeration on my part that is influenced by my father's assertion and complaint of such. The phantom center is large and spread out as opposed to small and precise; however, it is within the parameters of a well-designed speaker with the dispersion characteristics of the Revel line. He sits a long way from them in a large room.

 

[Dj7675]

I recon the tweeters inverted on one of them

I had an issue with a C208 that I purchased new with some sort of defect or wiring issue. It was easily shown my measuring it with a MIC/REW. You can’t assume that a new speaker isn’t as it should be unfortunately.

 

[digitalfrost]

To say that the F206 pair doesn't image is an exaggeration on my part that is influenced by my father's assertion and complaint of such. The phantom center is large and spread out as opposed to small and precise; however, it is within the parameters of a well-designed speaker with the dispersion characteristics of the Revel line. He sits a long way from them in a large room.

Could be that your father simply prefers speakers with a narrower radiation pattern. I do. He should try some KEFs.

 

[possumtaters]

Don’t know if this is relevant but I had my Revel F36 speakers for months, purchase new from an AD, and thought they sounded “good” but didn’t think they imaged very well. One day, I pull the speakers away from their position, and throughly ensured I had both speaker wires connected to the proper polarity, at both the amplifier and the speakers. It was then I noticed the binding posted were labeled correctly with +/- but the colors on the binding posts were reversed, red for negative and black for positive. Switched things around and everything came to life.

 

[home_theatre_man]

Could be that your father simply prefers speakers with a narrower radiation pattern. I do. He should try some KEFs.

For his listening distance, I would agree. This is the fourth room in which his F206s have lived; the others were much smaller. He has always complained about difficultly in "finding" the center image, but it wasn't until after this latest move that he started talking about replacing them.

Since it is somewhat problematic to set up and take measurements in his room, I may try to grab a few minutes with the system of another acquaintance who uses F206s. That will at least give me a reference point.

 

[Dj7675]

For his listening distance, I would agree. This is the fourth room in which his F206s have lived; the others were much smaller. He has always complained about difficultly in "finding" the center image, but it wasn't until after this latest move that he started talking about replacing them.

Since it is somewhat problematic to set up and take measurements in his room, I may try to grab a few minutes with the system of another acquaintance who uses F206s. That will at least give me a reference point.

If you can can do a near field measurement it should show if there are any speaker issues I would think.

 

[Laserjock]

Any update on the “issue”?

 

[home_theatre_man]

Any update on the “issue”?

I haven't been able to take any measurements in his room yet or listen to any other F206s. However...

He did swap in his AVP from a different system and perform another Audyssey setup. I was able to listen to this EQ and see no reason to pursue any further troubleshooting except for academic reasons; I hear nothing subjectively off (in particular the treble is smoother and the "spread" of the center image is no longer noticeable) nor anything that might indicate a fault in his F206s on program, tone, or noise. He is also much happier with the way they sound.

I do not doubt that there a small difference in the way to the two F206 units will measure, but not anything that is outside of manufacturer tolerances.

At this point, I am attributing the symptoms to the Audyssey setup that was done with the AVR, or to a difference between the processing in the AVR and AVP. Both used the same amplifier (the AVR was acting as a preamp only). When time permits, he is going to put the AVR back in and run another Audyssey setup to A/B to the first one, as well as the AVP.

 

[Alice of Old Vincennes]

Audyssey is likely the problem.