Mate digital main speakers (Genelec 8341a) with analog subwoofer (KEF KC62)?

[seattle-michael]

Source device is an iMac Pro with USB-A and USB-C ports.

I already own a KEF KC62 subwoofer that has stereo line-level (analog) RCA output jacks to high-pass the signal to main amplifier and speakers. I'm on the verge of buying a pair of Genelec 8341a. I noticed the 8341a has a digital output and is designed to work with Genelec subwoofers. I haven't yet seen any provision for third-party subwoofers.

If I want to use my existing KEF subwoofer, would it make more sense to run the 8341s with analog inputs? Would this approach be incompatible with the GLM software?

 

[seattle-michael]

OK, I found this in the manual:
"The AES/EBU input supports two channels of audio in a single cable. The DIGITAL OUT male XLR connector carries an unaltered copy of the digital input signal. This enables daisy- chaining of up to four monitors."

So it seems the sub could run off this daisy chain with some kind of AES to analog converter. But it seems inelegant to have a DAC just for a subwoofer.

 

[stevenswall]

GLM will work with the 8341 with analog inputs. It's controlled via Ethernet cable and doesn't require digital input unless you have a genelec woofer that you want to manage the bass on some monitors like the 7271 that only does digital.

 

[seattle-michael]

GLM will work with the 8341 with analog inputs. It's controlled via Ethernet cable and doesn't require digital input unless you have a genelec woofer that you want to manage the bass on some monitors like the 7271 that only does digital.

OK, that helps.

I wonder if I'm the only one who would try to use a non-Genelec subwoofer with GLM-managed main speakers. It's not clear to me whether the unmanaged subwoofer should be switched on when the GLM runs its frequency sweep calibrations. Any opinion on that?

I'm thinking I might also use a lower-than usual crossover frequency to stay out of the way of the speakers that are already calibrated?

 

[stevenswall]

OK, that helps.

I wonder if I'm the only one who would try to use a non-Genelec subwoofer with GLM-managed main speakers. It's not clear to me whether the unmanaged subwoofer should be switched on when the GLM runs its frequency sweep calibrations. Any opinion on that?

Genelec speaker calibration does not require having and input/source connected over xlr since the tone is generated from the glm unit and sent to the speakers over an ethernet cable.

 

[seattle-michael]

Genelec speaker calibration does not require having and input/source connected over xlr since the tone is generated from the glm unit and sent to the speakers over an ethernet cable.

Oh I see -- that's how they isolate the speakers during the calibration tone sweeps. So the third-party sub won't make a sound during calibration whether or not it's on.

I speculate that using the KEF sub might be detrimental to the whole set up unless it's crossed at such a low frequency that it could not interfere with the 8341 sound.

 

[stevenswall]

Oh I see -- that's how they isolate the speakers during the calibration tone sweeps. So the third-party sub won't make a sound during calibration whether or not it's on.

I speculate that using the KEF sub might be detrimental to the whole set up unless it's crossed at such a low frequency that it could not interfere with the 8341 sound.

Might be okay for filling the lowest frequencies. I've tried dual PSA subs, quad SWARM subs, and found a single GLM capable sub to sound by far the best, with the least effort. Spent a couple of hours for days playing with the other setups and REW and autoEQ and such on a DSP. Maybe DIRAC would be better, perhaps the new Dirac Live Bass Control software can do it, but the price for a unit with that is $4000, so instead I bought a $2500 used Genelec subwoofer and a demo GLM unit and mic and have $1500 in my pocket.

 

[Cortes]

I have the same doubts. I own some 8331s, and I'm think of buying a small subwoofer. The logic option looks like a Genelec one, where I can use my GLM kit. However, the smallest Gen subwoofer that suppots GLM is huge for my room. I want a small subwoofer like the Kef KC62.

I want to setup all with the GLM kit. The only think the GLM can do is to vary the parameters of the 8331s, but can't touch the KC62. BTW, since I have all digital AES, the XLR out from the 8331 to the KC62 (with a XLR->RCA adapter) will transform into analogue?. I don't see how 8331 can communicate with the subwoofer, it should be setup in the GLM, but not sure if possible.

 

[seattle-michael]

I don't have my Genelec speakers yet, but everything I've found suggests my KC62 has the two disadvantages you listed:

1. Can't be controlled by GLM. A workaround may be to use Room EQ Wizard. (I haven't yet learned whether that can also calibrate phase?)
2. Analog input only.

So maybe I wouldn't have bought the KC62 if I'd known I was going with Genelec mains. On the other hand it's amazing how little mechanical vibration the KC62 transmits to the surface it's resting on, I guess due to the horizontally opposed drivers. This is a plus for me in an apartment.

 

[hege]

I speculate that using the KEF sub might be detrimental to the whole set up unless it's crossed at such a low frequency that it could not interfere with the 8341 sound.

Wrong. You can independently set 50-100hz highpass filters to any Genelec-speaker with GLM.

Of course it requires quite a bit of tweaking and measuring if you want the best results, tuning both Kef's lowpass and GLM highpass for good summing. I believe all GLM filters are very steep 48dB/oct, and Kef probably is much less, so results might be hit and miss. Also proper delay settings might be hard to achieve as only the GLM mains can be delayed. Usually it's just easier to get some miniDSP box to handle everything if you don't know what you are doing (but the point of this forum is to push to learn right?).

 

[Cortes]

Wrong. You can independently set 50-100hz highpass filters to any Genelec-speaker with GLM.

Of course it requires quite a bit of tweaking and measuring if you want the best results, tuning both Kef's lowpass and GLM highpass for good summing. I believe all GLM filters are very steep 48dB/oct, and Kef probably is much less, so results might be hit and miss. Also proper delay settings might be hard to achieve as only the GLM mains can be delayed. Usually it's just easier to get some miniDSP box to handle everything if you don't know what you are doing (but the point of this forum is to push to learn right?).

If only Genelec would sell smal subs GLM ready all would be super easy.

 

[q3cpma]

If only Genelec would sell smal subs GLM ready all would be super easy.

That's what the 7350A is, no? Unless it isn't small enough, which would be strange.

 

[Cortes]

I don't have my Genelec speakers yet, but everything I've found suggests my KC62 has the two disadvantages you listed:

1. Can't be controlled by GLM. A workaround may be to use Room EQ Wizard. (I haven't yet learned whether that can also calibrate phase?)
2. Analog input only.

So maybe I wouldn't have bought the KC62 if I'd known I was going with Genelec mains. On the other hand it's amazing how little mechanical vibration the KC62 transmits to the surface it's resting on, I guess due to the horizontally opposed drivers. This is a plus for me in an apartment.

looks like the KC62 is high tech. The thing I don't get is that from video looks very easy to integrate the KC62 with speakers, why should be more complicated with Genelecs?

 

[Cortes]

That's what the 7350A is, no? Unless it isn't small enough, which would be strange.

7350A is perfect in normal cases, but for my particular application is huge.

 

[seattle-michael]

Wrong. You can independently set 50-100hz highpass filters to any Genelec-speaker with GLM.

Of course it requires quite a bit of tweaking and measuring if you want the best results, tuning both Kef's lowpass and GLM highpass for good summing. I believe all GLM filters are very steep 48dB/oct, and Kef probably is much less, so results might be hit and miss. Also proper delay settings might be hard to achieve as only the GLM mains can be delayed. Usually it's just easier to get some miniDSP box to handle everything if you don't know what you are doing (but the point of this forum is to push to learn right?).

That helps. Kiitos.

Yes, for me the learning is the real point of all this. So it could be fun to try to make it work.

Regarding getting the phase alignment right despite the inability to delay the KEF subwoofer, maybe I could delay the GLM mains far enough to be in phase with the KEF again? Or maybe it will turn out to be unnecessary anyway?

 

[seattle-michael]

looks like the KC62 is high tech. The thing I don't get is that from video looks very easy to integrate the KC62 with speakers, why should be more complicated with Genelecs?

I watched that YouTube video and then downvoted it. The Zero Fidelity guy probably shouldn't be reviewing equipment. He has no evidence for most of the beliefs he states with 100% confidence. God, I wish people would stop doing this.

While this may be similarly irresponsible, I tried measuring the KC62 in my untreated home office. It is not positioned ideally -- it's on a 21" (53cm) shelf so my daughters won't kick it by mistake. Also note my mic is not calibrated, and I'm just an amateur at taking these measurements. I'd be happy to drop the thing off with Amir if he wants to test it properly.

Something I haven't seen any reviewer mention about the KC62: It has RCA jacks for line-level stereo output on the other side of its adjustable high-pass filter. Yay! BUT when it detects a signal and powers itself on, it sends a loud thump and a fraction of a second of static noise to my amplifier and main speakers downstream. When the KC62 turns itself on, I see the woofers of my SuperZeros moving farther than I realized they could. So I will not be using that feature if my Genelec mains ever get here. It makes more sense to let the GLM manage the high pass as hege suggested.

 

[seattle-michael]

Now I've got a pair of Genelec 8341a and my KC62 on the shelf between them. I set the KC62 to the lowest crossover setting available.

In this graph the green line is the KC62, the purple line is both 8341a, and the red line is with everything on. The Genelecs have been calibrated with GLM and I think I managed to enable a house curve.

The KC62 has a phase inversion switch (0º or 180º), but that's it.

How would you proceed from here?

 

[Cortes]

@seattle-michael, how did you connect the 8341s to the KC62?

 

[seattle-michael]

I just used an 1/8" stereo Y adapter from my iMac's headphone port to send the same analog signal to both of them. I'm sure this will offend most audiophiles, but I wonder if they'd be able to hear any difference between the iMac Pro's built-in DAC and an outboard one. I tried the Apple dongle (which outperformed many DACs except for not reaching 2V), but it would send annoying clicks in the computer's sleep/wake cycle.

 

[Cortes]

I just used an 1/8" stereo Y adapter from my iMac's headphone port to send the same analog signal to both of them. I'm sure this will offend most audiophiles, but I wonder if they'd be able to hear any difference between the iMac Pro's built-in DAC and an outboard one. I tried the Apple dongle (which outperformed many DACs except for not reaching 2V), but it would send annoying clicks in the computer's sleep/wake cycle.

How can you control the volume of KF and Gennis in a syncronized way?. I only see via playback software.