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Equipping my home office with some Genelecs

semi, modified 12 Years ago.

Equipping my home office with some Genelecs

Youngling Posts: 5 Join Date: 9/25/09 Recent Posts
Hi

I currently connect my PC soundcard to my stereo amp and my pair of passive speakers to the amp. I'd like to replace the amp and the speakers with a pair of Genelec speakers, connected to the PC.

My application is games, movies and music. Far from professional use. It seems a surround set might make sense, but I think I'd rather get two awesome speakers than 5 great speakers.

My current setup is about the price of one 8240A and I'm hoping for improved sound quality, especially clearer voice dialogue.

room configuration

My home office is about 3m wide * 3m deep * 2.5m high.

The wall that I am facing is concrete, covered with painted fiber glass wallpaper. It is fully covered by an open bookshelf, with my PC display on a shelf in the middle, a floor-standing speaker on either side, and a stereo amplifier on a shelf above my display.

The wall on my left is painted concrete and has a 150cm x 140cm window, a 100cm x 50cm radiator below the window, and light full-height curtains.

The wall on my right is double plaster sheet with painted fiber glass wallpaper and has a 205cm x 65cm hollow wooden closet door and a 90cm x 120cm metal whiteboard.

The wall behind me is concrete with painted fiber glass wallpaper and has a 85cm x 205cm hollow wooden door in the right corner and the rest (180cm wide) is fully covered by a bookshelf similar to the one on front.

The ceiling is concrete with a coating that has very rough texture. The floor is plastic. There are no other furniture than the bookshelfs in front and back and my office chair.

The bookshelf is 29.5cm deep and there's 2cm between the wall and the back of the shelf so 31.5cm in total as the shelf is fully open. The shelves are 18mm thick varnished pine tree and can easily hold more than enough weight.

I calculated based on the width and depth of the 8250A that ((286 mm) * cos(30 degrees)) + ((278 mm) * sin(30 degrees)) = 38.7 centimeters based on the recommended angle for the speakers being 30 degrees. Protruding 2cm in the back and 7cm in the front, it would be 5cm forward from the middle position.

The same calculation for 8240A gives us ((237 mm) * cos(30 degrees)) + ((223 mm) * sin(30 degrees)) = 31.7 centimeters so it would be just about flush with the front of the shelves on its frontmost edge if touching the wall.

I'm leaning towards your DSP products because I can't really improve my room acoustics much and the automatic calibration by GLM could help. However I'd rather not get a subwoofer unit, so DSP SE products are a no-go.

the questions

Based on my calculations, it seems that if the Iso-Pod of the 8250A is at most 20cm deep, it would be able to fit securely on my shelves. Otherwise, the front of the Iso-Pod would start protruding from the front of the shelves, which seems bad. I didn't find the dimensions of the Iso-Pod, but even if it would fit, would the 8250A still be too large for the shelves, possibly because it could not be placed optimally from the audio quality (reflections etc) viewpoint?

What about the 8240A then? It clearly fits securely, but will I get acoustical problems?

How much space do I need to leave between the top of the speaker and the bottom of the shelf above? How about towards the books on either side? I suppose there's both an acoustical and a thermal viewpoint in this.

My head is about 1m from my display when gaming, less than that when working, and a bit more when watching movies. However the middle shelf is 1m wide, and there is a 3.5cm x 3.5cm vertical wooden support pillar in the front on either side. To obtain optimal listening angles, the speakers would have to go where the pillars are. But that's impossible, so the speakers need to be placed on the side shelves. That would mean a listening angle of 40-45 degrees instead of 30. Is that bad? How near can the speakers be to the front support pillar to avoid reflections and such?

On the other hand, a 6010A would fit between the support pillar and the PC display on either side (14cm wide spaces). They would have to be flush with the front of the shelves and the PC display surface. Then there would be some distance to the back wall. Would the distance to the wall or the large display area and the support pillar right next to it be a problem?
christophe-anet, modified 12 Years ago.

Re: Equipping my home office with some Genelecs

Jedi Knight Posts: 188 Join Date: 3/23/09 Recent Posts
Hello,

Thanks for your post and detailed description of your room setup. Most helpful.

First, some comments about your room. Having identical width and depth is of course not the best from an acoustical point of view (identical standing waves and minimas and maximas horizontally in the room). So, you are right that our DSP solutions will provide very good results that are more difficult - if not impossible - to achieve with analog monitors.

The placement of the monitors against the wall is a very good position - no more acoustical cancellation from the wall behind the monitor at low frequencies. Our DSP systems will automatically calibrate each monitor for this type of radiation load (hemispherical loading = against a wall). Now, of course the monitors need to physically sit and rest properly on the shelve or - even better acoustically - on separate floor stands.

As you describe your setup the 8240A can fit perfectly your room. The critical dimension you have not mentioned is the listening distance. I would guess that it will be around 1.2 meter (?) and hence the 8240A are matching well your setup. The 8250A may be slightly too big and over-powerful for such a short listening distance. Of course, it is all your choice.

How much space do I need to leave between the top of the speaker and the bottom of the shelf above? How about towards the books on either side? I suppose there's both an acoustical and a thermal viewpoint in this.


There is no need to leave much space above the monitor as long as enough air can flow towards the back of the monitor to provide sufficient cooling. As a preventive measure you can leave 5 cm, that will be enough. For the books on the side, they can be placed very close to the monitors, no problem there.

Depending on your listening distance - average 1.2 m ? - the monitors will have to be placed on either side of the structure of the bookshelf to form a perfect equilateral triangle with your head. Then, you could move your setup so that the distance between the monitors (once on either side of the bookshelf) match the distance to your ears. That will give you the perfect 60 degree stereo opening between L an R monitors.

Now, to achieve proper stereo imaging and especially a sharp phantom mono image, the L/R angle should not exceed say 70 degree. Beyond this angle your brain starts to loose the mono image.

Concerning the 6010A setup, yes it would fit on the bookshelf. The distance to the PC display is not a problem as the 6010A features a DCW waveguide which controls the sound directivity. As a general rule the distance to the back wall should be minimized, but with a typical bookshelf such as the one you describe (29.5 cm depth) such remaining distance will not be a problem acoustically.

Hope this is helpful.
Best regards,
semi, modified 12 Years ago.

Re: Equipping my home office with some Genelecs

Youngling Posts: 5 Join Date: 9/25/09 Recent Posts
Hi and thank you for a fast, informative reply.

While the room depth and width might differ by 10-20cm or so from each other, this is something I can't change. To maximize shelf space for books and ease floor cleaning, can't use floor stands either.

When I specified the bookshelves, I did not pay attention to the placement of the speakers - it seems the support pillars between the middle and side shelves are exactly where I should place the speakers to obtain a perfect equilateral triangle between my head and the speakers. This is mainly dictated by my preferred viewing distance to my PC display, the surface of which is flush with the front of the shelves.

A horizontal slice through the shelves: wide side shelf | 3.5cm support pillar | 14cm free space | 69cm PC display | 14cm free space | 3.5cm support pillar | wide side shelf.

I calculated that by placing a pair of 6010A to the free space between the display and support pillars I would get 85cm for listening distance, which would translate to about 70cm viewing distance for the display. However I wasn't really planning to get just 6010A...

On the other hand, the 8240A would have to be placed on the side shelves, which would give me at least 1.28m listening distance or more depending on how far from the support pillar the speakers really are. This would translate to a viewing distance of 1.1m or more.

My preferred viewing distance is 70cm-90cm to the display. It seems this would be perfect for the 6010A setup. Instead the 8240A setup would put my listening angle between 70 and 84 degrees instead of the optimal 60 degrees. So I would still be within the 70 that you gave as a limit, when leaning back, but would start to lose the phantom image when leaning forward.

Should have figured this thing out before building the shelves. One way to solve this would be to bring the PC display and my footrest outwards from the shelves, which is not trivial either. Or reconfigure the widths of the shelves between the pillars.

I guess I don't have any questions for the time being. Need to figure out what do to with the shelves so I can purchase. Thanks.