Need help! KEF R11 very subdued

[HarmonicTHD]

I am afraid that if you like your B&Ws you need to train your ear to the KEF sound. BTW, from the picture your stands seems so high (3 feet, maybe?), why?

Or apply EQ….

 

[PatentLawyer]

You don’t have any sort EQ / room correction profile on created using the B&Ws, right?

 

[HelloAJ]

You don’t have any sort EQ / room correction profile on created using the B&Ws, right?

No eq correction.

 

[tonycollinet]

The previous owner used the speakers with high -end McIntosh gear. Unfortunately before I picked up the speakers he had sold the amp, so couldn't test.

Sorry to say it - but I read that and immediatly thought it sounded sketchy as hell.

I think there is a significant chance he has blown the tweeters. And probably knew it.

 

[Koeitje]

Sounds like a blown tweeter. Can you measure the response?

 

[NTK]

May be OP can run a sweep using REW's generator from a computer. Play it at a reasonable level. Watch the sweep frequency being played, and see if the sound output goes away at an unreasonably low frequency.

 

[HelloAJ]

When I unLink the knobs and (set the woofers to off) I can still hear sound from the middle driver...is the above method best to test a blown tweeter?

 

[tonycollinet]

When I unLink the knobs and (set the woofers to off) I can still hear sound from the middle driver...is the above method best to test a blown tweeter?

Your crossover into the tweeter is at 2.9KHz. Try an online tone generator at 2KHz, and at 5Khz (Turn your volume way down, set the 2KHz, then turn the volume up until it is clearly audible but not too loud, then try the 5Khz)

If the tweeters are blown you'll be getting very little sound at 5Khz.

Try setting balance fully left and fully right to test each speaker in turn.

You might need to try some freqencies on either side of 5Khz (I'm deaf at 6KHz due to tinnitus). Also worth trying this with your other speakers first to hear what the two tones should sound like. Your ears are less sensitive at the higher frequency so it'll sound naturally less loud even at the same level.

Online tone generator

Online Tone Generator - generate pure tones of any frequency

www.szynalski.com

EDIT : To get a little more objective, get an SPL meter on your phone. Measure the output of the speaker with this at the two frequences. Repeat with your other speakers. (Keep the speaker to phone distance constant throughout)

 

[-Matt-]

@HelloAJ How did you get on with the various troubleshooting ideas suggested?

Were you able to establish if any of the drivers had failed?

Or was the problem more subtle, i.e. due to being used to brighter speakers?

One further idea... If you don't yet have any measurement gear you can probably use your B&Ws to learn the sound of a missing tweeter. Since those are 2 way, if you disconnect the high frequency terminals (and don't have links in place) you should get only the mid and low frequencies from the woofer. Does this give a similar sound to your R11s?

 

[HelloAJ]

Your crossover into the tweeter is at 2.9KHz. Try an online tone generator at 2KHz, and at 5Khz (Turn your volume way down, set the 2KHz, then turn the volume up until it is clearly audible but not too loud, then try the 5Khz)

If the tweeters are blown you'll be getting very little sound at 5Khz.

Try setting balance fully left and fully right to test each speaker in turn.

You might need to try some freqencies on either side of 5Khz (I'm deaf at 6KHz due to tinnitus). Also worth trying this with your other speakers first to hear what the two tones should sound like. Your ears are less sensitive at the higher frequency so it'll sound naturally less loud even at the same level.

Online tone generator

Online Tone Generator - generate pure tones of any frequency

www.szynalski.com

EDIT : To get a little more objective, get an SPL meter on your phone. Measure the output of the speaker with this at the two frequences. Repeat with your other speakers. (Keep the speaker to phone distance constant throughout)

Just did some (subjective) initial tests. At same volume level, 5k frequency is louder on 705s2 than the R11s. Is that to be expected? I have a Radioshack spl microphone so will do a more scientific, objective test tomorrow.

 

[tonycollinet]

Just did some (subjective) initial tests. At same volume level, 5k frequency is louder on 705s2 than the R11s. Is that to be expected? I have a Radioshack spl microphone so will do a more scientific, objective test tomorrow.

Your speakers may have different sensitivity. You need to check the difference in level on one speaker, compared with the difference on the other.

 

[-Matt-]

Just did some (subjective) initial tests. At same volume level, 5k frequency is louder on 705s2 than the R11s. Is that to be expected? I have a Radioshack spl microphone so will do a more scientific, objective test tomorrow.

I think the fact that you hear anything at all at 5kHz likely means that the tweeter isn't blown.

I could be wrong (others will confirm) but I think the typical failure mode is total failure - I.e. no sound above crossover, rather than attenuated output.

Maybe test one R11 speaker at a time to confirm that both tweeters are giving some sound at 5kHz.

 

[-Matt-]

Your speakers may have different sensitivity. You need to check the difference in level on one speaker, compared with the difference on the other.

Just to explain this a bit more in case it isn't clear...

Tony is saying that you should adjust the volume level on your amp or source so that the 2kHz tone plays at the same volume on each speaker. This might require two different volume levels as reported by the amplifier.

Eg: With the B&W speaker the volume knob may be at 12 O'clock position. To get the same volume with the 2kHz tone with the Kef speaker you might only need to be at 10 O'clock.

Once you know the two volume settings to use, you then try with the 5kHz tone and see if it is significantly louder or quieter with the Kef (when using the volume settings you just found).

Looking at the curves posted earler in the thread, they should be fairly close. You might hear a bigger difference at higher frequencies (i.e. 10kHz if you can hear that far up). Addiitionally this would be further from the mid-tweeter crossover and should therefore give a sharper contrast if the tweeter had failed.

Edit: When trying to adjust or compare levels, I'd probably do it with my ear close to the tweeter, rather than from your normal listening position. This will help to take the tweeter height and room acoustics out of the equation.

Honestly, I'd expect a blown tweeter to be absolutely obvious - but it is difficult to judge from your description how large of a difference you are hearing. This is why, around here, we like measurements!

 

[Battlebeast]

I said height wise as it is a multi driver array. Horizontally it's great, which is what you're saying, so we are both saying exactly the same thing.

I get a great sense of height as well. It’s a 3d like bubble. Really noticeable with HT content as the center channel gets in on it too. I’ve had or tried 4 different speakers for the center and none of them came close to being able to place the voices on the screen like the 650c. I can sit on the floor in front of the TV at around 2’ from the speaker and the voices still appear to come from the screen. It’s an 82” screen.

 

[raindance]

The troubleshooting ideas so far assume a passive crossover just removes frequencies from the speaker, which isn't correct. They simply attenuate them. So, this speaker, with a 2.9 kHz crossover point to the tweeter, will still play 5 kHz through the mid range driver, just at an attenuated level. It sounds like this may be what it is doing. It would be best to measure the frequency response to be sure.

Personally, I can hear a blown tweeter in seconds with a couple of test tracks containing delicate cymbal sounds I know well.

 

[Zapper]

The measurement techniques are great, but a blown tweater should be obvious when playing white noise at low volume and putting one's ear next to the tweeter. The presence or lack of a sharp hiss is easy to hear.