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Loudspeaker design advice needed. Mini-array Viston FR10 drivers Answered

Hi all,

I'm about to get started on my first set of loudspeaker cabinets. Since quite some time I have 8 Visaton FR10 drivers lying on a shelf and I want to use those. After some research on diy loudspeaker cabinets I came up with the design in the attached drawing. Before I start building a pair of these, I'd like to have some advice on the design. I'd like to keep the costs as low as reasonably possible :).

Questions I have and some design considerations:
- Are the tubes correctly dimensioned? I used the "vented box calculator" over here to get the dimensions for a cabinet with one driver. I doubled the area of the tube and placed two of them in the cabinet.
- I plan to clad the inner walls and the backside of the drivers' frame with convoluted foam. Do I need to fill the inner volume with some kind of polyester wool as well?
- I want to use the speakers with my "Serious Amp". Will that work?
- I planning to build the speakers without a filter. Is that wise?

- The four drivers in each cabinet are in pairs series // parallel, to get a joint impedance of 8 Ohm.
- As I understand it from the various forums / websites, it's best to place the drivers in a vertical line. However, the cabinet becomes too tall to fit in my tiny livingroom. I just don't have the floorspace to place them. Am I going to regret that decision?

Your advice is appreciated!

Y.

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Downunder35m

2 years ago

Can't go into all of your design details but maybe some of them...
To save in height or width you can place the speakers either side of the box.
To keep the directional properties you can use "reflectors" or simply a box-in-a-box design.
I used this a few times for small desktop speakers but they used a tweeter, two mid range and one sub.
Only problem I found when combining speakers in an array is unwanted disturbance.
For this reason I prefer to use fully sealed speakers whenever possible only leaving the low frequncies to standard speakers and the problem of creating the righ enclosure for them.
No matter how you wire your speakers it wil be next to impossible to have them all do the exact same thing at the exact same time.
There was a slow motion video on Youtube showing this in a system with 8 speakers but I can't find the link anywhere, sorry.
Another problem I noticed when it comes to "the perfect sound" is the frequency in relation to the internal space of the enclosure.
Ok, too hard, let me try again:
Especially at low frequencies you can only produce a proper soundwave if the space allows for a full wave to build up.
For example at 10kHz you need little over 3cm to be able to fit the full wave into the enclosure.
But at just 100Hz you already need 340cm to do this.
That is where tubes and reflectors come into play to create a path that is long enough to support a full wave at the desired frequency.
To get the most out of four broadband speakers it might make sense to use a crossover and different frequencies for each.
This way you can use much smaller internal space for 3 of them and can use one for the low frequencies in a seperate internal enclosure to get the most "boom" out of it.
I know it means much more additional calculations and internal (fully closed) walls but I think you could still be able to shrink the overall size a bit like this.
Considering the power level I can't really recommend using the speakers as you suggest and without a crossover, at least not if good sound is prefered over just loudness.

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ynzeDownunder35m

Reply 2 years ago

Thanks for the clear advice! I like your idea of separate spaces into one enclosure. I'll do some testing with that and the use of one or more filters. To be continued...

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Downunder35mynze

Reply 2 years ago

Keep in mind that you can use the empty space behind and around the small enclosures too ;)
Meaning, to safew space you can mount the base speaker tin the back with the reflector tube going out the front.
Works great if the speaker is meant to be placd in a corner anyway.