Mission 782 - Bright Treble

[Thompsonuxb]

He should use thick speaker cables but the interconnects make no difference........ :O

You're catching on, finally.

I think you misunderstand, you say use thick speaker cables & yet interconnects make no difference. you see no problem with that statement.

So there is a difference between bell wire and a thick cable yet this does not tranasfer to interconnects.... somethings wrong with you mister.

Thin cables on a speaker cause voltage drop because of the low impedances involved, and the voltage drop is uneven across the audio band because the impedance of a speaker varies across the audio band. B&W specify a maximum resistance value of 0.1 ohm for speaker cables to ensure good fidelity. Interconnects have no such issue, because the input impedance of the typical amplifier is far higher than the cable resistance, or impedance if you prefer.

What?

So the 75ohm or something like that impedence on digital coax cables have no value?

anyone who knows the value can help me out here, thanks.

The characteristic impedance of a cable is only relevant at radio frequencies.

lol.... I tried using a standard interconnect, single leg once from my amp to my sub - it did not work.

but you do realise we are talking electrical signals across a conducter - the source is doing exactly the same thing to the amp that an amp is doing to a speaker - you understand this. the same laws apply from point A to point B across the conducters. You understand that?

Not really. Could you explain further?

I=V/R

Your argument makes no sense as you seem to only want to apply the established laws when it suits. Suggesting speaker cable's operate from a different law to interconnects when both are conducters transfering an electrical signal, then go on to imply only one of these can affect their application is stupid.

I give up.

to the op - pls ignore this distraction. I was off today and had time on my hands..............

 

[lindsayt]

Jumpingjackflash90, do you, by anyy chance, currently hve the speakers facing directly at your ears?

Have you tried adjusting the toe-in of the speakers and the position of the speakers within the room?

If you listen to the tweeters and midrange units off-axis you should get less treble than on-axis.

Pushing the speakers nearer or further from the walls will also change the tonal balance.

It's always worth experimenting with the position and angle of any speakers within any room to get the tonal balance that is most pleasing to you at your normal listening position.

 

[TrevC]

He should use thick speaker cables but the interconnects make no difference........ :O

You're catching on, finally.

I think you misunderstand, you say use thick speaker cables & yet interconnects make no difference. you see no problem with that statement.

So there is a difference between bell wire and a thick cable yet this does not tranasfer to interconnects.... somethings wrong with you mister.

Thin cables on a speaker cause voltage drop because of the low impedances involved, and the voltage drop is uneven across the audio band because the impedance of a speaker varies across the audio band. B&W specify a maximum resistance value of 0.1 ohm for speaker cables to ensure good fidelity. Interconnects have no such issue, because the input impedance of the typical amplifier is far higher than the cable resistance, or impedance if you prefer.

What?

So the 75ohm or something like that impedence on digital coax cables have no value?

anyone who knows the value can help me out here, thanks.

The characteristic impedance of a cable is only relevant at radio frequencies.

lol.... I tried using a standard interconnect, single leg once from my amp to my sub - it did not work.

but you do realise we are talking electrical signals across a conducter - the source is doing exactly the same thing to the amp that an amp is doing to a speaker - you understand this. the same laws apply from point A to point B across the conducters. You understand that?

Not really. Could you explain further?

I=V/R

Your argument makes no sense as you seem to only want to apply the established laws when it suits. Suggesting speaker cable's operate from a different law to interconnects when both are conducters transfering an electrical signal, then go on to imply only one of these can affect their application is stupid.

I give up.

to the op - pls ignore this distraction. I was off today and had time on my hands..............

Once again, from the top.

Thin cables on a speaker cause voltage drop because of the low impedances involved, and the voltage drop is uneven across the audio band because the impedance of a speaker varies across the audio band. B&W specify a maximum resistance value of 0.1 ohm for speaker cables to ensure good fidelity. Interconnects have no such issue, because the input impedance of the typical amplifier is far higher than the cable resistance, or impedance if you prefer

 

[altruistic.lemon]

Speaker change, that's the fix.

 

[nima]

...Give Telluirum Q Blue speaker cable & interconnects a try. They will be a big step up (particularly over the Chord), and do have a subtle soothing effect on the upper mid/treble without sacrificing detail. I'm sure you would find a dealer with a loan set.

Disproportionate and pointlesss waste of resources.

The only disproportionate, boring and pointlesss thing here are your post.

Borrowing some cables costs nothing. (My advice to OP is to borrow some CDP while you're at it.)

 

[TrevC]

...Give Telluirum Q Blue speaker cable & interconnects a try. They will be a big step up (particularly over the Chord), and do have a subtle soothing effect on the upper mid/treble without sacrificing detail. I'm sure you would find a dealer with a loan set.

Disproportionate and pointlesss waste of resources.

The only disproportionate, boring and pointlesss thing here are your post.

Borrowing some cables costs nothing. (My advice to OP is to borrow some CDP while you're at it.)

If you borrow them, manage to convince yourself that they are somehow better than other wire, which they ain't, you then have to waste a huge and disproportionate amount of cash on buying the idiotic things. I find your semi-literate nonsense boring too, BTW.

 

[TrevC]

Speaker change, that's the fix.

Indeed. :dance:

 

[nima]

Thanks, still I bet I'm way more eloquent in your mother tongue than you are in mine though.

 

[bigfish786]

i had different missions to you, but i would definitely experiment with placement as has already been suggested. this did work for me. eventually.

 

[hammill]

...Give Telluirum Q Blue speaker cable & interconnects a try. They will be a big step up (particularly over the Chord), and do have a subtle soothing effect on the upper mid/treble without sacrificing detail. I'm sure you would find a dealer with a loan set.

Disproportionate and pointlesss waste of resources.

The only disproportionate, boring and pointlesss thing here are your post.

Borrowing some cables costs nothing. (My advice to OP is to borrow some CDP while you're at it.)

We have a different understanding of nothing.

Assuming the dealer will lend me some cables to try, I have to drive to the dealer, pay car parking ticket. Collect cables. Drive home. Listen to various cables. Decide on the cables I want (or not). Drive back. Pay car parking ticket. Pay for and/or return cables.Drive home. For me, the exercise costs £25 plus an afternoon (£50 minimum in my book) even if I don't buy any new cables. Sounds like an expensive waste of time to me.

 

[JumpingJackFlash90]

To all who have posted here - many thanks for your insightful and varied suggestions!

I will indeed experiment with placement and toe-in.

Re: Cabling - I can't say I've ever been too much of a believer in the difference made - whenever I have changed, I've always struggled to hear much difference - any perceived differences seem so slight (say, compared to the obvious change to the audio quality from new amp/speakers etc). However, that said - I haven't tried all the different cables in the world - and it stands to reason that the materials used to carry a signal path must have some effect on the physics of the signal/current etc

Coincidentally - I have today purchased at Musical Fidelity X-10D "valve stage buffer" to go between the CD and the Amp (had been thinking about getting one for years just as an experiment..not necessarily a knee-jerk reaction to any of the above suggestions). I'm wondering if this may tame the Marantz CD player a little...?

 

[JumpingJackFlash90]

To all who have posted here - many thanks for your insightful and varied suggestions!

I will indeed experiment with placement and toe-in.

Re: Cabling - I can't say I've ever been too much of a believer in the difference made - whenever I have changed, I've always struggled to hear much difference - any perceived differences seem so slight (say, compared to the obvious change to the audio quality from new amp/speakers etc). However, that said - I haven't tried all the different cables in the world - and it stands to reason that the materials used to carry a signal path must have some effect on the physics of the signal/current etc

Coincidentally - I have today purchased at Musical Fidelity X-10D "valve stage buffer" to go between the CD and the Amp (had been thinking about getting one for years just as an experiment..not necessarily a knee-jerk reaction to any of the above suggestions). I'm wondering if this may tame the Marantz CD player a little...

 

[nima]

We have a different understanding of nothing.

Assuming the dealer will lend me some cables to try, I have to drive to the dealer, pay car parking ticket. Collect cables. Drive home. Listen to various cables. Decide on the cables I want (or not). Drive back. Pay car parking ticket. Pay for and/or return cables.Drive home. For me, the exercise costs £25 plus an afternoon (£50 minimum in my book) even if I don't buy any new cables. Sounds like an expensive waste of time to me.

Go with a bike. Waste of time? I thought hifi was a hobby of WHF forum users. :?

 

[Thompsonuxb]

We have a different understanding of nothing.

Assuming the dealer will lend me some cables to try, I have to drive to the dealer, pay car parking ticket. Collect cables. Drive home. Listen to various cables. Decide on the cables I want (or not). Drive back. Pay car parking ticket. Pay for and/or return cables.Drive home. For me, the exercise costs £25 plus an afternoon (£50 minimum in my book) even if I don't buy any new cables. Sounds like an expensive waste of time to me.

Go with a bike. Waste of time? I thought hifi was a hobby of WHF forum users. :?

lol.... I was going to suggest a daysaver about 4quid the last time i used one.

 

[JunglistJut]

I too have a pair of mission 782, brought from ebay with a lispy treble that is winding me up. They sound lovely apart from the S and T in voices being over emphasised with a hiss at the end.

I'm driving them with an Arcam Avr 300, bi amped (4x100), so power should not be the issue. My main source is an Apple TV, fed from Itunes upstairs and leading optically to the DAC in the avr. Files are cd and vinyl rips. I have a Arcam Alpha 7se as backup, which presents the same problem so it should not be the source at fault.

I have made reasonable improvements to the sound by re-building the crossover with higher quality components. Plus re-arranging which amplifier drives which driver.

One of the crossovers had a burn mark on the rear where a resistor had burnt out on the band pass filter. So I started by ripping out the filters for treble and mid bass then bought some solen capacitors to provide a high pass on the tweeter, large hand wound inductors (1.25mm air core) for a low pass on the mid bass.

Since they are bi amped, I didn't bother cutting off the bottom of the mid bass and just allow them to mix with the woofer a little. This may not not be such a good idea with a single amp since it may cause some impedance spikes at the frequency where the two woofers mix. I quite liked the result though, so they'll stay like that for now.

The inductors brought a lot of harshness off the mids where the melted one was playing too high and mixing with the tweeter.

I originally attenuated the tweeter with a couple of 1 ohm resistors in series, but this made it worse :/

I've since replaced the series resistors with a -3db L-Pad and this has done the most to tame the tweeters. I did mock up a -6 db L-Pad quickly with the tweeter out of the box but it sounded too quiet. I've been sat with them for about 3 hours now and I'm tempted to try the -6db again.

I've found a Morel tweeter that will fit with minor modification. I'm tempted to buy a set, especially since Morel made the speakers in my friend's Green Mountain Audio speakers use Morel Tweerers and they sound amazing.

 

[JunglistJut]

I also tried another pair of tweeters from another pair of missions, same result ruling out a problem with the tweeters. All drivers cd resistance was in spec.

It's annoying really, reviews of this speaker said it had a smooth treble and the reviews on the tweeter itself say the same but that's not really my experience.

Perhaps listening to those Green Mountains has just spoilt me, but I'm determined to sort this since everything else about these speakers is very good indeed and I feel I'd have to spend a lot of money to find a superior speaker.

 

[hybridauth_Google_115561073878388351597]

Resistence values are not the best way to determine the problems with the Mid range drivers form Keraform.

Yes they will alter and increase to a point where they will just pop and loose continuity, but before that, the corrosion on the weldings will inflate and this will make the cone coil rub the walls of the magnet liner assembly. This creates drag and make the cone vibrate a lot less and produce a baffled sound... hence the bright trebles and Unbalanced feeling towards these otherwise brilliant speakers.

Solution is to replace by the superior but similar design AUDAX aerogel vented fixed pole drivers.

I'm studied the 782 flaw and brought a set exactly bacause of that flaw... they are completely undevalued as they WILL ALL fail due to the original Keraform drivers.

I brought them cheap and upgraded the drivers to AUDAX... of course in my case i had to do that sooner than later due to the shipping company damaging the drivers, catalizing the inevitable.

Full article and detailed instructions here : http://totaltechtalks.blogspot.com.es/2016/02/mission-782-repair.html

Hope this helps.