Genelec 8351B Teardown (2nd Disassembled)

[richard12511]

Thanks a lot.
I guess the 8361A would be a fairer comparison to the 8C.

Honestly, I doubt it. Doesn't the 8361 only extend like 2Hz deeper than the 8351? Main advantage of 8361 seems to be volume, but I think the 8C's advantage is more of an extension thing.

 

[Sparky]

Cheapest solution for digital into Genelec monitors, with the bonus of simultaneous digital and analogue outputs, people here may be interested in the Dolby DP564.

$250 on Ebay, does 7.1 or 5.1 over optical which is more than most people need. If you have external bass management you could use the additional channels set to "large" to feed other woofers, and each channel can be volume adjusted. (I believe they have delay settings too.)

Sorry mate. Missed your post. I'll look into that one.

 

[Jason K]

Some Amp, DSP board pictures added.

 

[Jokerbre]

Thank you

 

[q3cpma]

Couldn't find any THD data on the IRS20957S, the datasheets just say "improved THD and noise", hmmm....

 

[Sparky]

Some Amp, DSP board pictures added.

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Love this!

 

[dfuller]

IRS20957S powering Fairchild/ON Semi FDD770N15A N-channel MOSFETs for the amps, for all channels... Looks like they're doing a single-rail design for the high voltage (relatively speaking) power supply, if I had to hazard a guess here. I'm probably wrong on this one but it's somewhat hard to tell.

How they're getting different output power for the woofers vs the tweeter and midrange I don't know, because I'm not seeing a multi-rail supply. Maybe stepping level down in the STM32 SoC?

 

[Jokerbre]

 

[Sebastiaan de Vries]

IRS20957S powering Fairchild/ON Semi FDD770N15A N-channel MOSFETs for the amps, for all channels... Looks like they're doing a single-rail design for the high voltage (relatively speaking) power supply, if I had to hazard a guess here. I'm probably wrong on this one but it's somewhat hard to tell.

How they're getting different output power for the woofers vs the tweeter and midrange I don't know, because I'm not seeing a multi-rail supply. Maybe stepping level down in the STM32 SoC?

IRS20957S powering Fairchild/ON Semi FDD770N15A N-channel MOSFETs for the amps, for all channels... Looks like they're doing a single-rail design for the high voltage (relatively speaking) power supply, if I had to hazard a guess here. I'm probably wrong on this one but it's somewhat hard to tell.

How they're getting different output power for the woofers vs the tweeter and midrange I don't know, because I'm not seeing a multi-rail supply. Maybe stepping level down in the STM32 SoC?

Most likely just a lower impedance for the woofer and midrange driver as opposed to the tweeter. One supply rail for all three amps. All three amps seem to be similar.

 

[Sparky]

With subwoofers, they have immense headroom. I hit peaks of 102 dB last night. I never used to listen this loud, but the Genelec's sound so "effortless" that I don't notice how loud it is until I measure.

I have never listened to them loud without subwoofers, but I believe the 8351B's need to be matched with subwoofers (and correction) to transform into a big system. They just sound bigger and punchier with the right subwoofers and tuning.

One critical note, I use a relatively unusual steep 8th order crossover @85Hz, which for sure increases the headroom. The reason is that in my acoustics 8th order @ 85Hz. Provides the punchiest, and most even response.

This is crucial information and will definitely help me make s decision. Although my budget doesn't stretch to the 8351's, the 8341's are in budget and I feel they would be fine also.

Thank you for the pic of the SPL too, that really solidifies things for me.

 

[Sparky]

I have addressed your SPL concerns in my previous reply. With suitable subwoofers and proper tuning, there isn't a concern at all regarding SPL and your listening distance.

With regards to your LFE question. In the new scenario with the mini DSP SHD pre-amp, the OPPO downmix does embed the LFE signal into your Left/Right mix if you set the L/R speakers to "large" in the menu. I have done this before, and I didn't see any downside on it; the mini DSP with DIRAC will direct all low frequencies, including LFE, to the subwoofers.

Thank you once again Sebastiaan. Absolutely perfect info.

 

[Sparky]

Thank you once again Sebastiaan. Absolutely perfect info.

You are quite right on this by the way @Sebastiaan de Vries. I have just gone into my settings on the OPPO and changed the speakers to LARGE and even turned off the subwoofer and I still get a good subwoofer response in movie scenes that I know very well contain strong LFE information.

In light of this, does this mean I can disconnect my analogue connections and replace them with an Optical to achieve the same result?

 

[MrOtto]

Paper cones? Ask JBL, they should know a thing or two about paper cones woofers. They have just been making those since 1946 and still uses them today in high end home and PA speakers. I can't imagine they would use paper cones in professional PA cinema audio for example if durability was poor, which sees hours and hours of use every day, all year. Or use paper cones in speakers selling for thousand of dollars for home high end hifi.
I imagine paper cones can be produced with incredible light weight/stiffness ratio for this purpose.
It's not better just because it's different or new. But this is what many customers believe, and producers must make esthetic changes to the speakers they make to persuade customers.

 

[Pearljam5000]

Paper cones? Ask JBL, they should know a thing or two about paper cones woofers. They have just been making those since 1946 and still uses them today in high end home and PA speakers. I can't imagine they would use paper cones in professional PA cinema audio for example if durability was poor, which sees hours and hours of use every day, all year. Or use paper cones in speakers selling for thousand of dollars for home high end hifi.
I imagine paper cones can be produced with incredible light weight/stiffness ratio for this purpose.
It's not better just because it's different or new. But this is what many customers believe, and producers must make esthetic changes to the speakers they make to persuade customers.

Psychologically it's hard to swallow because paper is the most fragile material there is

 

[MrOtto]

Why does it have to be strong, if this is what you mean by "not" fragile (its durability is certainly proven)? Don't confuse stiffness with strength. Two different abilities.

 

[Sparky]

Psychologically it's hard to swallow because paper is the most fragile material there is

I thought that when I first learned of paper cones. Couldn't wrap my tiny mind around it.

 

[somebodyelse]

Couldn't find any THD data on the IRS20957S, the datasheets just say "improved THD and noise", hmmm....

IRAUDAMP6 reference design uses it, and has AP test data.

 

[q3cpma]

IRAUDAMP6 reference design uses it, and has AP test data.

Looking quite good, but I find very strange that the 1 kHz test tone (page 10) has a spike that's not a multiple of it (~1.8 kHz).

 

[HooStat]

Psychologically it's hard to swallow because paper is the most fragile material there is

How about we call it "wood composite"? Would that make it better?

 

[voodooless]

Psychologically it's hard to swallow because paper is the most fragile material there is

You shouldn’t eat it . Paper it itself is obviously not stiff, but is does flex very well. By adding addetives you can get the paper fibers to become stiff and flexible enough to use as a cone, and it does not have a lot of resonances, so the HF is mostly gentle. SB Acoustics has done one better and went all Egyptian and used papyrus fibers instead of paper.

I bet you you’ll bend or dent an aluminum cone much faster and easier than a paper one.