Single Revel F208 with low midrange output

[restorer-john]

The op ran a test to verify the discrepancy and stated that there wasn't an obvious difference between the L/R speakers.
This thread is public and could lead to other Revel owners looking closer at their systems.

Not exactly a set of $100 Edifiers speakers here and owners would expect a decent response from them if a batch of caps started to fail in the field.

Failed cheap electrolytic caps are simply not good enough in expensive speakers. End of story.

 

[617]

Yes, I have.

Failed cheap electrolytic caps are simply not good enough in expensive speakers. End of story.

I have no problems with Electros in a crossover but I've also never experienced failure.

Have you ever seen a poly or film and foil cap fail like this?

 

[Thomas_A]

I have no problems with Electros in a crossover but I've also never experienced failure.

Have you ever seen a poly or film and foil cap fail like this?

The one I had was a bulged electrolytic, resulting in poor frequency response.

 

[restorer-john]

Have you ever seen a poly or film and foil cap fail like this?

Usually films are usually used as bypass for electros in crossovers, so even if they failed, you may not know.

 

[Vovgan]

First of all, "Hi." I'm a longtime lurker on the forum. I have a pair of Revel F208s, one of which seems to be outputting 5-10 fewer db in the midrange than its counterpart. I purchased this pair used a few months ago, and, up until now had assumed that the disparity I was seeing in my room measurements was due to room anomalies and not the speaker itself. It was not as obvious as you'd think during critical listening and Dirac on my SHD did a pretty good job of correcting for it. Nevertheless, something has always felt slightly "sub-optimal" about this setup, and it's been nagging at me for so long that I've decided I can't ignore it any longer.

Lo and behold, it's definitely the speaker. I've taken some measurements from my listening position of both speakers in the exact same location in the room. The difference in the midrange is pretty obvious, proving it's not the room or my associated equipment causing this. Seems to me it's either an issue with the midrange driver or the crossover network. Is there any way to determine which one based on the measurements I'm sharing? Could it possibly be caused by faulty or out-of-phase wiring in the offending speaker? Thanks in advance.

Similar problem occurred to me a few days ago: lower midrange level on one of my f208 speakers, but also lower treble and some audible distortion. Living in Russia there is no way of purchasing a single f208 or even a pair now, so this problem made me really sad… until I noticed that one of the bolts holding jumpers on the rear side of the speaker was loose. Tightened it and the speaker is as new! Phew…

 

[Mistletoe]

This old thread has really made me reconsider my capacitor choices for the speakers I build. I've read mountains of questionable data saying capacitor type in crossovers matter, and lots saying there is no way it could matter. Then I thought "Well Revel does double blind listening tests, surely they could solve the electrolytic vs. film capacitors in crossovers debate." I started looking, and indeed they do have lots of bipolar electrolytics in their speakers. But they seem to use film caps in their tweeter circuits, is that confirmation that capacitor type does matter for the highs?

Then I found this thread of the Revel midrange crossover electrolytic failing and tell myself "Why go to the trouble of using electrolytics at all?" I'm already in the speaker and Dayton film capacitors aren't that expensive, so might as well just put them in anyway. I'm not a business, a few cents or dollars extra for a cap has no impact on me. I find it funny that Parts Express didn't even use electrolytics in the crossover for the ultra budget but highly regarded C-note kit. It's 3 Dayton film caps, 2 air-core inductors, and a 10W resistor and the whole kit with cabinets and drivers used to be $100! I don't think I've ever heard of a film cap failing and I have encountered lots of electrolytics in my life failing, although usually in powered equipment and not speaker crossovers. I think I'll just start doing film everywhere.

 

[defec1]

Maybe Revel under estimated the max voltage that the capacitor in question would see causing it to fail over time if one likes it loud. just replace it with a higher voltage quality cap. it won't hurt the sound and it will be a lot harder for it to get stressed.

 

[fcracer]

First of all, "Hi." I'm a longtime lurker on the forum. I have a pair of Revel F208s, one of which seems to be outputting 5-10 fewer db in the midrange than its counterpart. I purchased this pair used a few months ago, and, up until now had assumed that the disparity I was seeing in my room measurements was due to room anomalies and not the speaker itself. It was not as obvious as you'd think during critical listening and Dirac on my SHD did a pretty good job of correcting for it. Nevertheless, something has always felt slightly "sub-optimal" about this setup, and it's been nagging at me for so long that I've decided I can't ignore it any longer.

Lo and behold, it's definitely the speaker. I've taken some measurements from my listening position of both speakers in the exact same location in the room. The difference in the midrange is pretty obvious, proving it's not the room or my associated equipment causing this. Seems to me it's either an issue with the midrange driver or the crossover network. Is there any way to determine which one based on the measurements I'm sharing? Could it possibly be caused by faulty or out-of-phase wiring in the offending speaker? Thanks in advance.

View attachment 180037

Glad to hear you figured out what was wrong and were able to repair the speaker. However it really bothers me that Revel didn’t appear to step up.

It baffles me that no Revel retailer reached out to help you. If I owned a hifi store and carried Revel, I’d offer to give you a speaker myself so that 1. You’d have a positive experience with a brand I carry and 2. My hifi shop would get enough free publicity to cover the wholesale cost of one speaker.

Seems like basic business, and common sense.