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Revel M16 repair help / suggestions

muslhead

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I bought a pair of the m16's just as they were clearing out remaining inventory at their dealers at a good price.
My desire was to use them in our outside patio room. Good price for good speaker ... what could go wrong.
Due to structural and WAF limitations i was forced to suspend them against the side wall, just below the ceiling (at about a 12 ft height).
I bought a solid mount that would handle the weight and work with my side wall. The mount requires you to attach a plate to the speaker so i drilled 4 holes into each speaker (glossy black mdf).
I mounted the speaker and was severely disappointed as it was boomy and absent of high end. I expected the boomy as it was near the wall so i plugged the port, added a sub and crossed over to the the m16's handle 80hz and up.
Result was just as disappointing no highend. I pulled a speaker down, plugged in a rear speaker from my video room (only other passive speaker i had) and found the high was fine. This told me it was the Revels. So I ran REW (for the Revels and my PSB imagine rear) and quickly discovered this

Revel & PSB FR sweep.png


The revels start to fade around 1k hz. So i reached out to the dealer who has since contacted revel with no response.
The first thing (and only thing) that came to mind beyond a defective speaker (not one but two? --- probably not) is my holes that i drilled. They were placed inbetween the port and posts. Looking at an internal pic there is nothing there as the xover sits on the bottom and the speakers are on the other side.
I needed a way to look inside but could not find a way to remove the woofer (or tweeter) so i removed the binding post which revealed ... nothing. The wires to both speakers from the cross over are held away from the rear speaker by insulation so i dont believe they were severed. I did feel (not see) that on both speakers one of my holes (out of 4) actually pierced the rear of the speaker creating an open hole to the back. The other 3 were not deep enough and did not pierce the rear mdf wall.
So, i am thinking (while revel picks their nose and my dealer does nothing as it is deferring to revel) they wont take them back because i drilled the holes and i caused the problem (which may be true). So i am likely stuck with a non functioning speaker due to my potential error. Viewing through the binding post access, and my limited visibility, the worst case it is only a disconnected or cut wire as i did not go anywhere near the individual drivers nor the xover. So i was thinking if i could pull the woofer and see what the problem was i could potentiall fix it if it or at least better understand the problem.

I am going to assume revel wont warrant them because of my drilling as they will say i breached the terms of the warranty so i have nothing to risk looking. If i can get at the internals via removing a driver. Sorry for the lengthy back story but bottom line is does anyone know if i am SoL or is there a way to remove individual drivers (there are no visible screws) for me to get a peek at what i may be up against.

As for my outdoor patio, I have already found a replacement and got them mounted and working but I want to keep the revels and will use them as f+r in my HT if i can get them back to functioning correctly

Any help here would be appreciated.
 
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muslhead

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Throwing all caution to the wind, i went for it. The ring around the woofer just pops out revealing a bunch of screws and two screws for the tweeter. I removed all screws and was able to get the woofer out which allowed me to get my hand inside the cabinet. I can see the one pilot hole i drilled touched nothing (there is nothing within 3-4 inches of my hole). I now have access to the xover if needed. The tweeter had a couple of wing nuts that i had to unscrew from within the cabinet. Once that was complete both drivers are free.
But where should i go next. Test the tweeter? the cross over? but how?
Suggestions would be appreciated since i have never done this.
TIA
 
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muslhead

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After removing the wires from the xover, i measure the resistance across the tweeter terminals with my multimeter and got OL.
I also measured the restance across the wires coming from the crossover which read ~ 95ohms

From this (OL) can i assume the tweeter is bad?
I did the xover measurement just to see what reading i would get and to confirm my mm is ok, but dont know if that is a reasonable reading.

Is there anything else i can do to confirm my mm reading other than apply a signal and listen? Touch the terminals to a 9v battery?
 

DonH56

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If the tweeter reads open with an ohmmeter chances are it is a bad tweeter. Which makes me wonder if you did it (easy to overdrive them in an outdoor setting) or it happened at the dealer's (were they open-box or new n box?) Either way you'll probably have to contact your dealer or Harman for replacement tweeters.
 

DVDdoug

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i measure the resistance across the tweeter terminals with my multimeter and got OL.
You should measure in the ballpark of 4-8 Ohms. The DC resistance isn't exactly the same as the impedance but it's close and maybe a little lower. "OL" means overload, higher than the meter-range can measure, or more-likely a completely-open connection... an open-blown voice coil (infinite resistance) or open connection to the voice coil.

I also measured the restance across the wires coming from the crossover which read ~ 95ohms
That's probably fine. I'd expect to measure open there too because there is usually a series capacitor, which will measure infinite DC resistance, but I don't know anything about the crossover design and it's probably OK.
 
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muslhead

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If the tweeter reads open with an ohmmeter chances are it is a bad tweeter. Which makes me wonder if you did it (easy to overdrive them in an outdoor setting) or it happened at the dealer's (were they open-box or new n box?) Either way you'll probably have to contact your dealer or Harman for replacement tweeters.
I thought the only way i could have done damage is if i had drilled into them. Upon my first power up (it was done at low volume on a 100 w amp), they sounded that way (no upper end). So, i doubt i blew them and thought i could have damaged them with my drilling (which i confirmed did not happen). What doesnt make sense is why both were bad. I very much doubt they came that way from harman so i am concerned it may have been the initial start up i did (but it was at low volume).
Does it appear that the xovers are still good based upon my readings or do i need to do some other test? I am concerned that if it was the start up and that blew a tweeter if it could have damaged the xover too? Or are the xovers not sensitive to volume?
I have contacted the dealer and asked for a new set of tweeters do i need to ask for xovers too?
Thanks for your help, Don
 
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muslhead

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You should measure in the ballpark of 4-8 Ohms. The DC resistance isn't exactly the same as the impedance but it's close and maybe a little lower. "OL" means overload, higher than the meter-range can measure, or more-likely a completely-open connection... an open-blown voice coil (infinite resistance) or open connection to the voice coil.


That's probably fine. I'd expect to measure open there too because there is usually a series capacitor, which will measure infinite DC resistance, but I don't know anything about the crossover design and it's probably OK.
Thanks, Doug
 

DonH56

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I thought the only way i could have done damage is if i had drilled into them. Upon my first power up (it was done at low volume on a 100 w amp), they sounded that way (no upper end). So, i doubt i blew them and thought i could have damaged them with my drilling (which i confirmed did not happen). What doesnt make sense is why both were bad. I very much doubt they came that way from harman so i am concerned it may have been the initial start up i did (but it was at low volume).
Does it appear that the xovers are still good based upon my readings or do i need to do some other test? I am concerned that if it was the start up and that blew a tweeter if it could have damaged the xover too? Or are the xovers not sensitive to volume?
I have contacted the dealer and asked for a new set of tweeters do i need to ask for xovers too?
Thanks for your help, Don
Crossover designs are of all sorts and without knowing the circuit I could not say if the readings are good or bad. But an open tweeter is almost certainly bad so I would start there. It is very strange that two would be bad like that. If you have the tweeter out you can visually inspect the connection at the terminals to the voice coil and see if the wires themselves from terminals to voice coil look OK.

You could look for damage on the wires to and from the crossover to see if somehow they got wrapped around the drill bit but based upon your description that seems unlikely.
 
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muslhead

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Crossover designs are of all sorts and without knowing the circuit I could not say if the readings are good or bad. But an open tweeter is almost certainly bad so I would start there. It is very strange that two would be bad like that. If you have the tweeter out you can visually inspect the connection at the terminals to the voice coil and see if the wires themselves from terminals to voice coil look OK.

You could look for damage on the wires to and from the crossover to see if somehow they got wrapped around the drill bit but based upon your description that seems unlikely.
All the wires from the xover look good ... no discoloration, well connected and either soldered or glued. I doubt there is anything wrong with the xover but i dont know what i dont know. The xover is about 6 in from the drill hole. The drill bit went into the cabinet no more than about a 1/4 inch on one hole. The cabinet is thick and my bit was short. I am 100% confident looking locations, distances and condition of components, the drilling was not the cause.
What now makes sense, because you mentioned and my intnernal visuals confirming it was not the drill, is it could have been blown on the startup. I dont see how (the amp power is less than max rating of speaker by 50%) but it seems like the best possibility ... even better than a harman defect.
The tweeter is incased within the plastic wave guide so i cant really see inside of it at the voicecoil. All that is visible (other than plastic casing) it terminal posts which look fine. I see nothing that appears non-normal.
IF the tweeters blew at intial power on, can a xover be damaged too? I know they are all different but if using passive components i would think not, no? Possible but not likely?
 

DonH56

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I was thinking of the wires on the back of the tweeter from terminals to voice coil. I've not had my Revel tweeters out so do not know what they look like from the back but would not have expected the waveguide to cover the back.

Yes, a crossover could be damaged, but in general I have seen very few blown crossovers and many blown tweeters. Bearing in mind that I am not a speaker designer and am many years from my tech days, the ones I recall had fairly obvious visible damage like burned resistors or coils and bulging capacitors. That said a component could die after a surge without much external evidence. Since both speakers are bad the usual suggestion to measure and compare the two is invalidated, alas.

I would not be too quick to point at the amp as my memory may be faulty, but I seem to remember it being discussed on AVS or some other audio forum. Like you, it just seems odd you would have received two speakers with bad tweeters.
 
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muslhead

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I was thinking of the wires on the back of the tweeter from terminals to voice coil. I've not had my Revel tweeters out so do not know what they look like from the back but would not have expected the waveguide to cover the back.

Yes, a crossover could be damaged, but in general I have seen very few blown crossovers and many blown tweeters. Bearing in mind that I am not a speaker designer and am many years from my tech days, the ones I recall had fairly obvious visible damage like burned resistors or coils and bulging capacitors. That said a component could die after a surge without much external evidence. Since both speakers are bad the usual suggestion to measure and compare the two is invalidated, alas.

I would not be too quick to point at the amp as my memory may be faulty, but I seem to remember it being discussed on AVS or some other audio forum. Like you, it just seems odd you would have received two speakers with bad tweeters.


Thanks for your thoughts. At this point, since they are brand new, i just want them fixed.

Here are a coupla pics of the rear of the tweeter
No wires., Nada, just plastic and terminal posts
IMG_20220522_113534.jpg
IMG_20220522_113530.jpg
 

phoenixdogfan

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At one time I considered Revel, but after reading a couple of experiences regarding customer support and service, I don't think I'll ever spend a nickel on a Revel speaker.
 
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muslhead

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In my case the dealer is working (or not) with revel. As of last Friday, I have only gotten the chirping of crickets for on my inquiry for help.
Not sure where the breakdown is but i am not impressed up til now
 

AnalogSteph

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Service aspects aside, this is an opportunity to study how well the woofer breakup modes are suppressed in these... which is not overly, by the looks of it. I wonder whether you can readily hear the peak a little over 5 kHz, it sure falls well short of the desired 20 dB suppression.
 
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muslhead

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Service aspects aside, this is an opportunity to study how well the woofer breakup modes are suppressed in these... which is not overly, by the looks of it. I wonder whether you can readily hear the peak a little over 5 kHz, it sure falls well short of the desired 20 dB suppression.
no, i heard nothing coming from either Revel driver at that frequency.
 

wwenze

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Does it appear that the xovers are still good based upon my readings

No idea man but tweeter xovers usually either measure open-circuit to DC or you get a value that is the value of another parallel path. Sometimes (personal experience) it can find a path from the resistors from the woofer side, not magic here because in this case if you study the schematic it will make sense and if you cut the loop and measure the individual components they will make sense too.

OTOH I have also encountered blown tweeter series cap. Blown meaning altered capacitance value and can conduct DC.

If you have the ability to solder/desolder stuff, I would test both xover's capacitors out-of-circuit and confirm if they are blown or not. If these are blown, nothing protects the tweeters from DC and they will blow too. It is possible that a large spike or prolonged DC can blow the capacitors and tweeters in one shot.
 
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muslhead

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Quick updates --- I eventually received two new tweeters (thanks Revel - great customer service) and installed them. That fixed the problem. The xovers were not damaged, only the tweeters so i now have a repaired set and my brand new backup pair sitting in unopened boxes on my closet shelf, i purchased in case the damaged ones were unfixable.
 
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