Hello, I am a big fan of DIY audio, and am trying my best to build a great sound system for relatively cheap, with decent used equipment.
I have 2@ B&W 604 S2 speakers,
fed by 2@ NAD 218 THX amplifiers in mono-block mode/vertical bi-amped to the speakers' passive crossovers, 1 amp for each speaker,
fed by a Marantz SR7011 pre-amplifier in Stereo mode.
It was all working nicely, until my kid pulled out the Mini-RCA input cable from my iPod to the Marantz amp. That made the dreaded big POP noise; after that, both midrange tweeters are entirely dead. No scratching or humming, just 0 midrange. It sounds like the high tweeters and the low woofers are working, but at this point, I'd like to somehow test all woofers/tweeters on both speakers and each speaker's internal crossover, to make sure it's all working. Since the problem is on both speakers, I can't tell whether it's a 2-speaker problem, or my amp/s has a problem. I have basic electronics knowledge and am very willing to learn. I have documentation for each component, if anyone needs me to upload them.
Is it the speakers, the woofers, the crossovers? or both power amps? or the Marantz pre-amp? How do I test, how do I proceeed, what do I do, where do I start?
I have several NAD 214 amps, that I can use instead of the 218's, to test if it's the 218 power amps. My fear is that the POP killed something in the Marantz pre-amp.
For later:
-I have collected 6@ NAD 214 amplifiers, which I will assign 1 amp in mono-mode to each surround sound channel for a 5.2.4 Atmos setup. I have all the speakers, subs, amps, I just never set it all up. The 2@ NAD 218 THX will remain in mono for the front 2 channels. I know that is overdoing it. I wanted to make an all mono-amp setup for fun, for relatively cheap.
-I'm not sure if there's a way to make the SR7011 mono-amp its 9 amp channels into 1 amp channel full force; I was hoping to use 1 mono channel for Center channel, but I can't tell from reading the manual if there is a way to make it work in mono-mode at 125 watts RMS.
-Subwoofer is 2@ B&W ASW610XP. I quite like them.
-I have 5@ ButtKicker LFE for the 5 seats for watching movies, and 5@ old Crown amps to power 1 to each ButtKicker; they want 1,500 Watts RMS each.
-Just for fun, I no longer measure my Franken-stereo in watts, but in horsepower. As of today, we are at 9,675 watts RMS = 13HP. Huzzah! 3/4 of the total HP goes to the ButtKickers, so it doesn't really count towards the sound system.
I have 2@ B&W 604 S2 speakers,
fed by 2@ NAD 218 THX amplifiers in mono-block mode/vertical bi-amped to the speakers' passive crossovers, 1 amp for each speaker,
fed by a Marantz SR7011 pre-amplifier in Stereo mode.
It was all working nicely, until my kid pulled out the Mini-RCA input cable from my iPod to the Marantz amp. That made the dreaded big POP noise; after that, both midrange tweeters are entirely dead. No scratching or humming, just 0 midrange. It sounds like the high tweeters and the low woofers are working, but at this point, I'd like to somehow test all woofers/tweeters on both speakers and each speaker's internal crossover, to make sure it's all working. Since the problem is on both speakers, I can't tell whether it's a 2-speaker problem, or my amp/s has a problem. I have basic electronics knowledge and am very willing to learn. I have documentation for each component, if anyone needs me to upload them.
Is it the speakers, the woofers, the crossovers? or both power amps? or the Marantz pre-amp? How do I test, how do I proceeed, what do I do, where do I start?
I have several NAD 214 amps, that I can use instead of the 218's, to test if it's the 218 power amps. My fear is that the POP killed something in the Marantz pre-amp.
For later:
-I have collected 6@ NAD 214 amplifiers, which I will assign 1 amp in mono-mode to each surround sound channel for a 5.2.4 Atmos setup. I have all the speakers, subs, amps, I just never set it all up. The 2@ NAD 218 THX will remain in mono for the front 2 channels. I know that is overdoing it. I wanted to make an all mono-amp setup for fun, for relatively cheap.
-I'm not sure if there's a way to make the SR7011 mono-amp its 9 amp channels into 1 amp channel full force; I was hoping to use 1 mono channel for Center channel, but I can't tell from reading the manual if there is a way to make it work in mono-mode at 125 watts RMS.
-Subwoofer is 2@ B&W ASW610XP. I quite like them.
-I have 5@ ButtKicker LFE for the 5 seats for watching movies, and 5@ old Crown amps to power 1 to each ButtKicker; they want 1,500 Watts RMS each.
-Just for fun, I no longer measure my Franken-stereo in watts, but in horsepower. As of today, we are at 9,675 watts RMS = 13HP. Huzzah! 3/4 of the total HP goes to the ButtKickers, so it doesn't really count towards the sound system.
I would start by unscrewing a woven Kevlar bass/midrange driver, removing the connecting wires then measuring the DC resistance across its terminals using the low ohms scale on your multimeter.
If the driver has not been blown, you should expect to get a reading of somewhere around 4 to 6 ohms.
If you don't currently own a multimeter, rapidly connect and disconnect a 1.5 V battery across the driver's terminals to discover if any sound is produced.
Let's take it from there.
If the driver has not been blown, you should expect to get a reading of somewhere around 4 to 6 ohms.
If you don't currently own a multimeter, rapidly connect and disconnect a 1.5 V battery across the driver's terminals to discover if any sound is produced.
Let's take it from there.
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Your thread title talks about midrange woofers.
But in the text you talk about midrange tweeters.
So what is it?
What is dead?
Are you sure there is no overcurent protection in the crossover?
From B&W Specification Sheet:
DM604 S2 drive units
1 x 25mm metal dome high-frequency
1 x 180mm woven Kevlar® cone bass/midrange
2 x 180mm paper/Kevlar® cone bass
Note that the OP says "It sounds like the high tweeters and the low woofers are working."
DM604 S2 drive units
1 x 25mm metal dome high-frequency
1 x 180mm woven Kevlar® cone bass/midrange
2 x 180mm paper/Kevlar® cone bass
Note that the OP says "It sounds like the high tweeters and the low woofers are working."
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Thank you Galu, I will proceed as soon as I can, to check the resistance on the cones. If I wanted to check all other woofer cones and tweeters on these speakers, would resistance for each of them also be 4-6 ohm? How where do I learn what the resistance of each part should be when I check it?
Thank you Adason, you must excuse my lack of perfectly precise, accurate, specific, engineering language. The YELLOW midrange kevlar sound-making device (insert part name here) on both speakers give 0 sound. It is the midrange yellow kevlar cone, I don't know if it's called a tweeter or woofer or cone. The 2 black woofers on the bottom of both speakers give sound. The small shiny device at the top for treble gives sound. I'm trying to figure out why the YELLOW cones are 100% dead.
Thank you Adason, you must excuse my lack of perfectly precise, accurate, specific, engineering language. The YELLOW midrange kevlar sound-making device (insert part name here) on both speakers give 0 sound. It is the midrange yellow kevlar cone, I don't know if it's called a tweeter or woofer or cone. The 2 black woofers on the bottom of both speakers give sound. The small shiny device at the top for treble gives sound. I'm trying to figure out why the YELLOW cones are 100% dead.
You can check a tweeter and a woofer the same way as you would check the midrange - as I shall call the yellow woven Kevlar driver!
Note that 4 to 6 ohm is an estimate. What you don't want to see are the readings obtained when the multimeter probes are (a) touching each other, or (b) not touching each other.
Midbass for sure. Its a nice one, it would be pitty if they are gone. I would assume tweeters would be first to blow on impuls overload, but you never know.
Weekend update, I took apart both speakers and checked all woofers on both speakers, both yellow midrange woofers measure 4.6 ohm, and all 4 bass woofers measure 7.6 ohm. That's a big yay, my sweet speakers still work.
I also removed the 2@ mono-block NAD 218 power amps from the equation and tested both speakers on 2@ NAD 214 power amps in mono-block, same problem again, 0 sound at all from the yellow midrange woofer on both speakers. In my mind, that leaves only 2 possibilities:
-The internal crossover is messed up inside each speaker, which I really doubt, or
-There is something awry in the Marantz SR7011 pre-amp, which is my suspicion.
How do I proceed?
Thank you kindly for the help.
I also removed the 2@ mono-block NAD 218 power amps from the equation and tested both speakers on 2@ NAD 214 power amps in mono-block, same problem again, 0 sound at all from the yellow midrange woofer on both speakers. In my mind, that leaves only 2 possibilities:
-The internal crossover is messed up inside each speaker, which I really doubt, or
-There is something awry in the Marantz SR7011 pre-amp, which is my suspicion.
How do I proceed?
Thank you kindly for the help.
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You don't have a pair of working speakers, Just for trying...
P.s. regarding the possible faults, It could be a broken fuse. I doubt that it's in the crossover boards, needs ro be investigated..
P.s. regarding the possible faults, It could be a broken fuse. I doubt that it's in the crossover boards, needs ro be investigated..
The individual drivers may have tested OK, but there is still a fault within your speaker enclosures.
We have to suspect the crossover, so post photographs of the crossover board(s) in one of the speakers.
I do know that there's no mention in the DM 604 S2 User Manual of fuses or other protection devices.
(Note that a preamp fault would not affect the midrange drivers without affecting the other drivers.)
If we can't spot the problem with the crossovers there is a Service Manual for this speaker, but it costs $30 to purchase: https://www.emanualonline.com/elect...s2-600-series2-service-manual-emo-376711.html
EDIT: The link includes the statement: "This manual is suitable for Windows XP, Vista, 7, 8, and Mac".
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I seriously doubt its preamp. There is no logical way preamp could cause mid in 3way speaker to be silent.
Everything points to the component in mid crossover.
Progress, gentlemen.
You are completely correct, adason, well done! I found a burned resistor in the crossover:
R2 RR02992 resistor 1R5 11W Bennic
according to the parts manual for the speaker. It is melted black under the resistor, and 1 of its wires is completely broken off the circuit board.
Two other resistors are still attached, but slightly black/melted into a neighboring component.
Should I replace all resistors, or just the broken one?
Leave everything else alone on the crossover?
I suspect it will be a PITA to disconnect all 12 wires and extract the crossover, but I am quite excited with the discovery and ready to proceed. Thanks for helping me. I have been eager to fix these speakers ever since they popped, but didn't know where to start. This is great.
What brand resistor should I buy? Bennic?
Can you send me a link? What website should I buy from? I'm in Denmark and have no idea what store to order from, nor what resistor is good quality for a speaker.
You are completely correct, adason, well done! I found a burned resistor in the crossover:
R2 RR02992 resistor 1R5 11W Bennic
according to the parts manual for the speaker. It is melted black under the resistor, and 1 of its wires is completely broken off the circuit board.
Two other resistors are still attached, but slightly black/melted into a neighboring component.
Should I replace all resistors, or just the broken one?
Leave everything else alone on the crossover?
I suspect it will be a PITA to disconnect all 12 wires and extract the crossover, but I am quite excited with the discovery and ready to proceed. Thanks for helping me. I have been eager to fix these speakers ever since they popped, but didn't know where to start. This is great.
What brand resistor should I buy? Bennic?
Can you send me a link? What website should I buy from? I'm in Denmark and have no idea what store to order from, nor what resistor is good quality for a speaker.
Attachments
There's :
https://elektronik-lavpris.dk/p148300/ax9w-6k8-resistor-9w-5-6k8/
The only real importance with those resistors - is the size, type, resistance and power rating. So it needs to be physically there, needs to be ceramic to take some heat, and then the number on top, showing the right resistance and power.
Sorry - had to edit, since I started going into repair mode - before I found out that you included the actual schematic 😊
Absolutely measure the rest - just to be sure. But since both the double woofers and the little shiny tweeter works - like you already tested - then the filter should be fine. It can never hurt to be sure and make some control measurements and see if any values have changed way too much though.
https://elektronik-lavpris.dk/p148300/ax9w-6k8-resistor-9w-5-6k8/
The only real importance with those resistors - is the size, type, resistance and power rating. So it needs to be physically there, needs to be ceramic to take some heat, and then the number on top, showing the right resistance and power.
Sorry - had to edit, since I started going into repair mode - before I found out that you included the actual schematic 😊
Absolutely measure the rest - just to be sure. But since both the double woofers and the little shiny tweeter works - like you already tested - then the filter should be fine. It can never hurt to be sure and make some control measurements and see if any values have changed way too much though.
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Just extract it somehow and replace the component. Ah, you meant from the speakers...yes, that's a fuss! See if it's there some allowance...
Seems like the filter is just held in place by 4 small plastic clips. Squeezing them on each side with some "pointy" tongs, usually with a bit of wiggle - can let them go of the hole in the filter board, and then you should be able to lift the filter out quite a bit, to be able to work with it
Could be a bit of a fiddle - PITA - but it is definitely worth soldering those components properly, rather than finding out it go loose after you put everything back together.
Could be a bit of a fiddle - PITA - but it is definitely worth soldering those components properly, rather than finding out it go loose after you put everything back together.
It is possible that other components in the mid frequency (MF) crossover section have been damaged, e.g., inductor L3 in series with burned resistor R2.
I would regard all four components in the MF section with suspicion.
To measure L3, L4 and C2 you require a multimeter capable of measuring both inductance and capacitance.