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8330 rattle noise and clipping (red LED). Quality issue?

laparn, modified 6 Years ago.

8330 rattle noise and clipping (red LED). Quality issue?

Padawan Posts: 39 Join Date: 6/20/15 Recent Posts
Hi!

I could (finally) spend some time with my beloved 8330:s today. Cranked up the volume somewhat when family is away. But, I noticed two "issues" that puzles me which I need to be advised upon.
Music from Spotify (High quality streaming) on a Macbook Pro (OS X 10.9.5) => M2Tech Hiface 2 => Benchmark DAC1 PRE (analogue out) => Vovox Sonorus XLR 2m => 8330SAM. Benchmark volume at approx 10 o'clock (30%), Macbook volume at approx. 90-95%.

1. When playing some tracks the red LED flash intermittently and rather frequent. Both speakers show same "symptom". No audible distortion or noise though, just red LED. No unusual tracks played (consumer pop) and neither extreme SPL. I measured 88dB @1.2m with iPhone app "Decibels" which at least fairly indicate in what dB region I play. I mean, not calibrated, but should still do a sufficient job. The fault tolerance can´t be that big.

Why does this occur? It´s not even close to "party volume" and far from the 104dB stated in the specifications.


2. When playing the VERY demanding track "Deviation" with Biosphere, an extremely strange noise come from one of the speakers. It appears to be channel dependant though, cause when shifting XLR:s, the noise moved to the other speaker. The "music" appears to be almost channel symmetrical but there could be "hidden" frequencies the 8330:s cannot play at audible SPL:s that can be noticed. There is a clear and loud rattling/crackling noise like something is really loose inside. SPL: 76dB @1.2m.
I know the frequencies in this track is more than low but the speakers should handle that anyway. Correct? I have previously played this track (from CD) at MUCH higher SPL:s on both Event Opal and Dynaudio Contour 1.3SE without any symptoms. The only sound/noise heard is bass reflex port "blow" noise due to heavy air movement. Even my cheapish Koss Porta Pro headphones plays this track without any noise and can also play the low(er) frequencies that I´d say the 8330:s can´t.

Any ideas? Are these correct behaviours?
If so, I must say I am a bit disappointed. This is professional equipment and since the SPL:s are so "low" I´d claim both symptoms must/should/can be categorised under "distortion". Or not? Still, I must say it doesn´t ooze quality which is one the top attributes I associate with Genelec.

Thanks!
laparn, modified 6 Years ago.

Re: 8330 rattle noise and clipping (red LED). Quality issue?

Padawan Posts: 39 Join Date: 6/20/15 Recent Posts
Did a retake on issue "1".

To result on the same SPL 88dB @1.2m, I lowered the Macbok volume to approx. 40% and increased the Benchmark volume to 2 o'clock (60%). No LED flashing! :?:

Is there a voltage out from Macbook/M2Tech Hiface 2 causing input overload to the speakers? Or what is happening? Please advise what I recommended volume setting is using analogue input to speakers.

Issue "2" still showed same noise even with volume settings mentioned above.

Thanks.
ilkka-rissanen, modified 4 Years ago.

Re: 8330 rattle noise and clipping (red LED). Quality issue?

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi,

1) My first question would be that why do you want to introduce additional DA/AD conversions while you could connect your speakers directly from the digital S/PDIF output of the M2Tech Hiface 2 and preserve highest quality possible? Why do you want to have the Benchmark DAC in between? :)

8330's analogue inputs can accept up to +24 dBu/~12 volts RMS level which is beyond what your signal source can output. Can you let me know more details about your test setup? A video clip would be great and explains more than many words! Which tracks you were playing? Does the "Decibels" have any frequency weighting options enabled, such as A weighting? Typically most microphones found in handheld devices can not record any low frequencies (below ~200 Hz) which makes them pretty useless as accurate SPL meters. You could easily have much higher SPL at low frequencies than the app shows. Also please notice that the SPL specification of our speakers are averaged between 100 Hz to 3 kHz. At low frequencies the output capability is much lower.

2) I analyzed the track with a spectrum analyzer to see what happens there. You can see the result below, it's a short clip (time stamps shown) showing the spectral content of left (upper) and right (lower) channels. You can see all the information is concentrated at low frequencies, there is very little content above 500 Hz. The right channel has higher level which would explain why only other channel is causing the problems. You can also see about 25 Hz tone in both channels. A track like this is very demanding for a small speakers as 8330 with limited low frequency output capability. Since there isn't any content beyond low frequencies, your ears are lead to believe that the SPL isn't high although the speakers are working really hard. Comparison to Event Opal is not very useful because it is a much larger speaker, equivalent to our 8x50. Dynaudio Contour 1.3SE is also a larger passive speaker which output can be much higher depending on the amplifier power available. A video clip of the event of this would be much helpful as well! I am quite sure the noise you are hearing is just the amplifier clip sound which is a result of high amplitude low frequency content in the material. 8330s are great speakers but one has to remember they are still small which means their low frequency output is quite limited. A subwoofer is much recommended if high SPL at low frequencies is needed.

laparn, modified 5 Years ago.

Re: 8330 rattle noise and clipping (red LED). Quality issue?

Padawan Posts: 39 Join Date: 6/20/15 Recent Posts
Hi,

1) My first question would be that why do you want to introduce additional DA/AD conversions while you could connect your speakers directly from the digital S/PDIF output of the M2Tech Hiface 2 and preserve highest quality possible? Why do you want to have the Benchmark DAC in between? :)

Digital connection is on the to-do list. ;) The reason of a DAC is dual minded. On one hand due to the multiple inputs (CD, computer, PS3 and streaming via optical) where the Benchmark is mainly working as a signal source switch. On the other hand, I used to have both Event Opals and 8030B:s, with analogue IN only where upsampling via the DAC made a huge difference. Also, I have recently added an F Two subwoofer that unfortenately do not offer digital processing. F Two?...due to livingroom estetics. :D Whenever you release an F Two SAM...I am first in line. ;)

8330's analogue inputs can accept up to +24 dBu/~12 volts RMS level which is beyond what your signal source can output. Can you let me know more details about your test setup? A video clip would be great and explains more than many words! Which tracks you were playing? Does the "Decibels" have any frequency weighting options enabled, such as A weighting? Typically most microphones found in handheld devices can not record any low frequencies (below ~200 Hz) which makes them pretty useless as accurate SPL meters. You could easily have much higher SPL at low frequencies than the app shows. Also please notice that the SPL specification of our speakers are averaged between 100 Hz to 3 kHz. At low frequencies the output capability is much lower.

No frequency weighing option. Only SPL "average". Do neither know if there are any frequency limitations. However, it was well within "decent" volumes and where, I´d say, a majority of the allround music consumer end up playing air guitar. As mentioned, when changing the volume "setting combination" between the iPhone and the Benchmark DAC1 Pre, with preserved SPL, the symptom disappeared. The red LED did not light when I lowered the iPhone volume to 40% and raised the Benchmark volume to 60%.
Still, even considering "Decibels" as non-reliable source for a similar "analysis", 88dB is still far from the specified 104db @1m. A specified figure must be possible to reach without distortion, otherwise I´d say it is irrelevant and false.
Tracks played when LED flashes red, iPhone volume @ 90-95%% / Benchmark volume @30%:
Talking Body (Gryffin Remix) - Tove Lo
Bank Rolls (Remix) - Tate Kobang
I´m gonna show you crazy - Bebe Rexha
Touch Me (edit) - Dolores Haze
Super 8 - Little Jinder
Flygplatsen - Amason
Röster - Djurparken


2) I analyzed the track with a spectrum analyzer to see what happens there. You can see the result below, it's a short clip (time stamps shown) showing the spectral content of left (upper) and right (lower) channels. You can see all the information is concentrated at low frequencies, there is very little content above 500 Hz. The right channel has higher level which would explain why only other channel is causing the problems. You can also see about 25 Hz tone in both channels. A track like this is very demanding for a small speakers as 8330 with limited low frequency output capability. Since there isn't any content beyond low frequencies, your ears are lead to believe that the SPL isn't high although the speakers are working really hard. Comparison to Event Opal is not very useful because it is a much larger speaker, equivalent to our 8x50. Dynaudio Contour 1.3SE is also a larger passive speaker which output can be much higher depending on the amplifier power available. A video clip of the event of this would be much helpful as well! I am quite sure the noise you are hearing is just the amplifier clip sound which is a result of high amplitude low frequency content in the material. 8330s are great speakers but one has to remember they are still small which means their low frequency output is quite limited. A subwoofer is much recommended if high SPL at low frequencies is needed.



This is sooo serious, Ilkka. Really, one of the things I love with Genelec. You take your customers importance to "another level". Taking effort into this concern in this way is MUCH appriciated! Thanks!!!

However. Yes, it is a demanding track indeed, and yes 8330:s are rather small. In general I praise music dynamics as it is made, hence I let quite songs play quite. Especially when playing in high quality gear, as the 8330:s for instance.
I have played this track many times and let the volume be as low I always set when playing this track. I.e. not unusual high volume. I even reduced the volume A LOT trying to eliminate the noise but it did not disappear even at very low volume knob position(s) as well as low in dB.
The app "Decibels" can record film and I ´ll sending one to you when I manage playing...without kids prefering to play Pippi Långstrump, Bamse and other top list music. :lol: