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Understanding the Genelec Ones design

Jimshoe

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There has been much discussion here (and elsewhere!) about the Genelec ones.

They are extraordinary - indeed, I've just ordered a pair!

Looking at them I can understand the logic and benefits for the coaxial mid and tweeter but what is the rationale for tucking the woofers behind the front baffle? Is it so they don't impinge on the smooth front surface and wave guide?

Or is there another reason? I've not read any discussion of this design feature. I wondered if it was some kind of dipole effect (like the slots in the sides of the Dutch & Dutch 8cs)?

Also, are there downsides to woofers only 'seeing' the world through slots in the speaker wall. It's not a common design feature.

Finally, I've read speculation on the size of the racetrack woofers in comparison to conventional cone drivers - some saying they are equivalent to 8in (or even 10in) ones. Looking at them though they appear much smaller in total cone area - is there some characteristic of this shape driver that makes them behave like larger cone ones? I'm curious.

I know loudspeaker design is quite an art and I'd love to hear the thoughts of the knowledgeable folk here.

Doug
 

Tangband

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There has been much discussion here (and elsewhere!) about the Genelec ones.

They are extraordinary - indeed, I've just ordered a pair!

Looking at them I can understand the logic and benefits for the coaxial mid and tweeter but what is the rationale for tucking the woofers behind the front baffle? Is it so they don't impinge on the smooth front surface and wave guide?

Or is there another reason? I've not read any discussion of this design feature. I wondered if it was some kind of dipole effect (like the slots in the sides of the Dutch & Dutch 8cs)?

Also, are there downsides to woofers only 'seeing' the world through slots in the speaker wall. It's not a common design feature.

Finally, I've read speculation on the size of the racetrack woofers in comparison to conventional cone drivers - some saying they are equivalent to 8in (or even 10in) ones. Looking at them though they appear much smaller in total cone area - is there some characteristic of this shape driver that makes them behave like larger cone ones? I'm curious.

I know loudspeaker design is quite an art and I'd love to hear the thoughts of the knowledgeable folk here.

Doug
Loudspeaker construction is mostly about physics.

The ones does many things right :

1. Crossover at 400 or 500 Hz is minimizing IMD distortion from midrange/tweeter .

2. The whole baffle is a waveguide

3. Using slots for the bass frequencies is not gonna compromise the sound quality .
 
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TurtlePaul

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Genelec claims that the reasoning is to not interupt the waveguide. This makes sense as they would need a much larger cabinet to have an uninterrupted baffle. However, I do wonder is they are effectively using the slot to create a bandpass alignment which would allow for more bass with less cone excursion.
 

Tangband

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Genelec claims that the reasoning is to not interupt the waveguide. This makes sense as they would need a much larger cabinet to have an uninterrupted baffle. However, I do wonder is they are effectively using the slot to create a bandpass alignment which would allow for more bass with less cone excursion.
I dont know exactly how they have managed to get such a deep bass , but a metal cabinet certainly helps . That - and clever dsp with a HP filter below the tuning frequency of the port , helps protect the drivers from going into distortion.
This is one big advantage with active dsp crossover that simply not can be done in a passive loudspeaker.
 

q3cpma

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Must read:
* AudioXpress review for the slot/waveguide patent: https://audioxpress.com/article/patent-review-loudspeaker-with-a-wave-guide
* Genelec's own whitepaper: https://downloads.ctfassets.net/4zj...l_Loudspeakers_with_Integrated_Waveguides.pdf

The basic concept is like a d'Appolito MTM, you get cancellation outside the two woofers which is engineered to match the directivity control of the waveguide. The slots are both a consequence of the waveguide being big enough to control directivity low enough (thus covering the woofers) and to make the effective woofer radiation sources further apart, lowering the cancellation frequency a bit.
 
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Jimshoe

Jimshoe

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Thanks guys, really interesting. Section 4.5 onward in the Genelec paper is really interesting.
 

fluid

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Now that's an idea I hadn't thought of. Would be cool.
It does create a bandpass having the woofer fire into a front chamber but it is not to allow more bass, you can see some simulations of the effect here. It creates an acoustic low pass filter.

https://www.audiosciencereview.com/...nalysis-screws-in-waveguide.22985/post-771454

The distance between the sources is what sets the directivity, the slot allows that to be modified relative to the woofer location. In the ones this affects the vertical directivity of the arrayed woofers.

The woofers are race track shaped to have them fit in the enclosure and work nicely with the overall design.
 

fluid

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judging by Amir's plot it doesn't realy seam to have any effect where the woofers play, or am I not seeing it?
The distance between the slots has a pronounced effect on the vertical directivity, the crossover is at 320Hz in the 8361A which is why there is an obvious change.

8361A Vert.png


Because of the low crossover point the bandpass peak is well out of the passband. In my simulation there were four sources so the horizontal and vertical were the same, there is only a vertical offset in the Ones so the effect is only on the vertical directivity.
 

dasdoing

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The distance between the slots has a pronounced effect on the vertical directivity, the crossover is at 320Hz in the 8361A which is why there is an obvious change.

View attachment 170603

Because of the low crossover point the bandpass peak is well out of the passband. In my simulation there were four sources so the horizontal and vertical were the same, there is only a vertical offset in the Ones so the effect is only on the vertical directivity.


comparing the 2 5"ers I prefer the vertical of the "traditional"....other than that narrowing at 2Khz-ish obviously


index.php


index.php
 

abdo123

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The distance between the slots has a pronounced effect on the vertical directivity, the crossover is at 320Hz in the 8361A which is why there is an obvious change.

View attachment 170603

Because of the low crossover point the bandpass peak is well out of the passband. In my simulation there were four sources so the horizontal and vertical were the same, there is only a vertical offset in the Ones so the effect is only on the vertical directivity.

I wonder what would happen if the crossover frequency is exactly at the baffle step at 450Hz. Would that increase the directivity of the speaker?
 

Pearljam5000

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There has been much discussion here (and elsewhere!) about the Genelec ones.

They are extraordinary - indeed, I've just ordered a pair!

Looking at them I can understand the logic and benefits for the coaxial mid and tweeter but what is the rationale for tucking the woofers behind the front baffle? Is it so they don't impinge on the smooth front surface and wave guide?

Or is there another reason? I've not read any discussion of this design feature. I wondered if it was some kind of dipole effect (like the slots in the sides of the Dutch & Dutch 8cs)?

Also, are there downsides to woofers only 'seeing' the world through slots in the speaker wall. It's not a common design feature.

Finally, I've read speculation on the size of the racetrack woofers in comparison to conventional cone drivers - some saying they are equivalent to 8in (or even 10in) ones. Looking at them though they appear much smaller in total cone area - is there some characteristic of this shape driver that makes them behave like larger cone ones? I'm curious.

I know loudspeaker design is quite an art and I'd love to hear the thoughts of the knowledgeable folk here.

Doug
Which Ones did you order?
 

Tangband

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The distance between the slots has a pronounced effect on the vertical directivity, the crossover is at 320Hz in the 8361A which is why there is an obvious change.

View attachment 170603

Because of the low crossover point the bandpass peak is well out of the passband. In my simulation there were four sources so the horizontal and vertical were the same, there is only a vertical offset in the Ones so the effect is only on the vertical directivity.
Having the crossover as low as 320 Hz in 8361 is touching the shroeder frequency , bringing almost the same advantage that Grimm audio has in their loudspeakers. The result is very good directivity. This cant be done in the same way in the smaller Genelecs because the baffle is to small.
 

Pearljam5000

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A pair of white 8361A

Have got a pair of 8050s on loan till the 8361s arrive - also gobsmackingly good.

Rapidly becoming a Genelec fanboy here!
Would love a comparison between the two because very few people heard them side by side and it's a hugh price jump so I'm wondering if it's worth it, thanks ;)
 
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