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Anyone integrated Genelec 8030 + SVS SB-1000 Pro subwoofer - without an external crossover/DSP?

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Zeeb

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You can use a splitter cable and use two different calibration presents, one for each room. The MiniDSP offers room correction but each preset is for one set of speakers in one room. The way to do multiroom is to use a set of synchronized streamers of your choice and separate room correction devices.
I didn't realise I could have just split the output (would have to check the load of both inputs to make sure, I just read). But balanced for the long wire-run to the second room is much preferable, while RCA for the subwoofer gives me more sub options - so I think the track I'm on with my DAC is ok. I'm not picky about the second room... As long as the main living room with sub is fairly accurate I don't mind if the second room is a bit whacky and there won't be a sub out there. Synchronised streamers - never heard of that one:)

I've attempted to model the Genelec 8030 low-frequency response using VituixCAD. To get the response corresponding as closely as possible to that with the "Bass Roll-Off" option activated, I needed to use a 2nd-order high-pass filter with Q=0.53 and set to a frequency of 53Hz. The match then seemed quite reasonable.

I've also added a model of the SVS SB-1000 Pro subwoofer to the simulations. To get a reasonable blending with the "Bass Roll-Off" option active on the Genelec 8030, I needed to use a 3rd-order (18dB/octave) Butterworth low-pass filter set to 70Hz on the subwoofer. The polarity of the subwoofer needed to be negative. The resulting frequency response functions are shown below.

Note that the filtering is far from optimal, as there is a very broad region of overlap between the subwoofer and the main speaker, and the individual responses are not very complementary (in the filter sense of the word). The reason for that is related to the fact that we are trying to use the "Bass Roll-Off" option as a pseudo-high-pass filter for bass management purposes, and its shape was not designed for that task.
View attachment 184278
Awesome information, thanks! The green line looks like a match. I will try those settings on the SB-1000 Pro (hopefully in a couple of weeks). Will have to read up about polarity. Maybe with the SB-1000 Pro's PEQ and the Genelec's other DIP switches I can flatten it somehow... sounds like room effects might overwhelm the 3dB wave anyway. Good to have a starting point though.
 
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witwald

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I will try those settings on the SB-1000 Pro (hopefully in a couple of weeks). Will have to read up about polarity. Maybe with the SB-1000 Pro's PEQ and the Genelec's other DIP switches I can flatten it somehow... sounds like room effects might overwhelm the 3dB wave anyway. Good to have a starting point though.
Here's a simulation with two sets of PEQ added. The results are much better.

The SVS PEQ specifications are:

Frequency: 31.5, 35, 40, 46, 50, 56, 63, 70, 80, 90, 100, 112, and 125Hz
Q (filter bandwidth): 2.0, 2.4, 2.9, 3.6, 4.8, 5.7, 7.2, 9.6 and 14.4

Hence, the PEQ values that I used (see below) appear to be usable.

PEQ1 = 50Hz, +1.9dB, Q=2.0.
PEQ2 = 90Hz, –3.2dB, Q=2.0.
1644054567368.png
 
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Walter

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I personally think that when it comes to bass, all the theorizing in the world won't mean squat when it comes to the actual response in your room. In most cases, that is so uneven without EQ that a calibrated mic + REW will outweigh any theoretically better slope and phase matching. I'm definitely interested in what you determine. I'm considering the exact same combo, or maybe the 8020D since my use is nearfield in a small room.
 

witwald

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Granted that the room response will place its imprint on the bass response of a loudspeaker system, theorising can still prove helpful as it permits the development of an understanding of what is going on behind the scenes. In some cases it can help avoid poor choices that might otherwise be made. Genelec have clearly added the "Bass Roll-Off" option to adjust some sort of loudspeaker–room interaction condition. The present potential application is to try to use it as a low-pass filter for subwoofer–loudspeaker bass management, and the theoretical plots indicate that it isn't as well-suited to that task. With the addition of a modest amount of PEQ, the blending results can be improved. The above were just some examples that can be used to, hopefully, provide some guidance prior to set up and in-room measurement and adjustment.
 
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Zeeb

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Here's a simulation with two sets of PEQ added. The results are much better.

The SVS PEQ specifications are:

Frequency: 31.5, 35, 40, 46, 50, 56, 63, 70, 80, 90, 100, 112, and 125Hz
Q (filter bandwidth): 2.0, 2.4, 2.9, 3.6, 4.8, 5.7, 7.2, 9.6 and 14.4

Hence, the PEQ values that I used (see below) appear to be usable.

PEQ1 = 50Hz, +1.9dB, Q=2.0.
PEQ2 = 90Hz, –3.2dB, Q=2.0.
View attachment 184340
That looks great; I will set this as a custom preset. Even if I was never to measure, this pseudo-high-pass filter as you called it with these tweaks could well be better than no high-pass; allowing a bit more volume without distortion at a higher crossover point.

I personally think that when it comes to bass, all the theorizing in the world won't mean squat when it comes to the actual response in your room. In most cases, that is so uneven without EQ that a calibrated mic + REW will outweigh any theoretically better slope and phase matching.
It means more than squat if you factor it in, but yes I've seen some example room responses that show huge bass over-boost, nulls etc., so I'm ready for that when I set up my first sub.

That's what these DIP switches on studio monitors are for after all - an EQ option, that for example with internal subwoofer EQ can be an adequate solution for many.

Note this poster https://www.audiosciencereview.com/...dio-monitor-review.14795/page-59#post-1071134
is satisfied with his pairing of the Genelec 8030Cs with a Genelec 7040A subwoofer - without external EQ using only a UMIK. Granted it's a designed Genelec pair, but he had to use:
- the default 7040A subwoofer 85Hz high-pass
- the 8030C Bass Roll-Off we've been discussing
- the -4dB Bass Tilt as well

It goes to show the bigitude of room effects but also that you don't always need external EQ.

I'm definitely interested in what you determine. I'm considering the exact same combo, or maybe the 8020D since my use is nearfield in a small room.
Hmm yeah I guess the 8020D might need an external crossover for a higher crossover point. Unfortunately it will probably be while before I get the sub, learn to use the mic etc. but I will report my experiences here. I might even rearrange my main speaker positions, and I should also learn the basics of acoustic treatment somewhere in there.
 
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Walter

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It means more than squat if you factor it in
Yeah, not saying to totally disregard recommended best practices as a starting point, but in-room response may mean that you eventually end up with settings that would not at first seem very optimal.
That's what these DIP switches on studio monitors are for after all - an EQ option, that for example with internal subwoofer EQ can be an adequate solution for many.
Yeah. Those are designed to correct "more or less" for less than ideal placement, but no reason not to use them if they also help integrate the sub.
Note this poster https://www.audiosciencereview.com/...dio-monitor-review.14795/page-59#post-1071134
is satisfied with his pairing of the Genelec 8030Cs with a Genelec 7040A subwoofer - without external EQ using only a UMIK. Granted it's a designed Genelec pair, but he had to use:
- the default 7040A subwoofer 85Hz high-pass
- the 8030C Bass Roll-Off we've been discussing
- the -4dB Bass Tilt as well

It goes to show the bigitude of room effects but also that you don't always need external EQ.
Yes, as you say, in combination with a mic and something like REW just to read the results, in some situations the built in tools may provide enough EQ in themselves that a separate EQ program or device is not needed except for displaying the measurement results.
 
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Zeeb

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I've also added a model of the SVS SB-1000 Pro subwoofer to the simulations. To get a reasonable blending with the "Bass Roll-Off" option active on the Genelec 8030, I needed to use a 3rd-order (18dB/octave) Butterworth low-pass filter set to 70Hz on the subwoofer. The polarity of the subwoofer needed to be negative.

Looking at the SVS manual, in the crossover settings it looks like you can only set the crossover point and slope... There doesn't seem to be a way to set Butterworth type in that section.

If I set the slope to 18dB, is that the same thing?

I'm confused because from my amateur reading 18dB is an 'odd-order' Linkwitz-Riley filter slope, not a Butterworth.

(I know LR and Butterworth are related somehow but I thought they had different -dBs at the crossover point and a different q-factor bend...
This might need too much technical knowledge for me to understand. All I really want to know is can I put the above suggested low-pass crossover setting into the SVS SB-1000 Pro?)

PS. I ordered the SB-1000 Pro.
 

witwald

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Looking at the SVS manual, in the crossover settings it looks like you can only set the crossover point and slope... There doesn't seem to be a way to set Butterworth type in that section.
That's correct. I believe that the SVS only uses Butterworth lowpass filters, and has no provision for using a Linkwitz–Riley filter type.
If I set the slope to 18dB, is that the same thing?
Yes, an 18dB slope setting is equivalent to a 3rd-order filter response function.
I'm confused because from my amateur reading 18dB is an 'odd-order' Linkwitz-Riley filter slope, not a Butterworth.
Linkwitz–Riley filter topologies are 'even-order' designs (e.g., 2nd, 4th, 6th etc.). The Butterworth filters are the ones that can be even-order or odd-order.
(I know LR and Butterworth are related somehow but I thought they had different -dBs at the crossover point and a different q-factor bend...
A Linkwitz–Riley filter is –6dB at its nominated cut-off frequency (the crossover point). Butterworth filters are –3dB at their nominated cut-off frequency.

There is a relationship between Butterworth filters and Linkwitz–Riley filters, which is relatively straightforward. Linkwitz–Riley filters are made up of two cascaded Butterworth filters. For example, a 2nd-order Linkwitz–Riley filter is made from two cascaded 1st-order Butterworth filters. They create a combined –6dB response from the two individual –3dB cut-offs caused by the Butterworth filters. A 4th-order Linkwitz–Riley filter is made from two 2nd-order Butterworth filters, and so on.

As you've mentioned, the Linkwitz–Riley filter has a much softer knee than the Butterworth filter of the same order. The Butterworth filters are known as 'maximally-flat', as they have a smooth response in their passband with a relatively sharp knee in the transition region.
This might need too much technical knowledge for me to understand. All I really want to know is can I put the above suggested low-pass crossover setting into the SVS SB-1000 Pro?)
You should be able to do just that. Good luck and let us know how it goes.
 
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Zeeb

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I see, LR filters are even-order but Butterworth can be either. Thanks for explaining:)
 

Tangband

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One must remember that all closed box standmount speakers or bass reflex loaded such has a natural rolloff of aprox. 12/dB oct ( closed ) and 24 dB/oct ( bass reflex ) below the resonance frequency.

What does this mean ? Well , you always listen to the combination of the acoustical AND electrical crossover from the speakers.

A typical closed box standmount loudspeaker with a HP electrical crossover at 80 Hz and 12 dB/oct , in reality has a acoustical roll off about 24 dB/oct . The walls also has some gain so this complicates everything further.

This is why a THX crossover has crossover slopes of 12 dB/oct HP filter for the closed box main speaker and 24 db/oct for the subwoofer.

The acoustical result will be close to 24dB/ oct both LP and HP = good result.

Further complications:

The Genelec 8030 has a electrical HP filter just below the bass reflex tuning point, making it fall off more than 24 dB/oct below the resonance freq. Its more close to 36 dB/oct acoustical.

Conclusion - Its very hard to integrate a 8030c with a random subwoofer without a proper HP crossover for the 8030.
A correct crossover for 8030 is available in Genelec 7050/7060 making perfect integration.
 
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