I have 4 Dayton ND91-8 speakers. Can someone design me a box or something

[The Torrent]

Hi, i have 4 Dayton ND91-8 speakers. Wouldn't mind turning them into some sort of sound bar type thing or something, dont really know.

 

Can someone design me a box? I attempted to use simulators and calculate stuff but it was a bit complicated .

 

The design i got in my mind is something like this:

 

Ill prolly them full range, and might install my own battery inside/alongside it or just use mains 12v (i have a bunch of 12v speaker amps i can use for them).

 

But no idea if i should be adding passive radiators or how big the box needs to be etc.... ? 

 

 

Thanks.

[Ahoy Hoy]

For the best sound the box will be infinite big.


https://www.diyaudioandvideo.com/Calculator/SpeakerBoxVolume/

[The Torrent]

On 3/31/2023 at 8:37 PM, Ahoy Hoy said:

For the best sound the box will be infinite big.


https://www.diyaudioandvideo.com/Calculator/SpeakerBoxVolume/

i want 1 box with 4 speakers in it.

 

say i made it like a center channel type thing box, with 2 of the speakers left channel and 2 right. 

do i need to put a spacer internally in the box to seperate left and right?

should i put anything inside the box like foam or cotton for dampening?

does shape of the box matter?

these r the type of questions i have, not neccecarily volume.

 

I have also heard that cube boxes are bad and the driver should be different distances from each corner of a box. idk how this works or what i should do with this information.

[cmndr]

TLDR: Don't design a speaker from scratch your first time making one. Don't design a super complex speaker your first time DESIGNING one. Don't build a speaker yourself if you think you'll come out saving money or having better sound - after you factor in time and resale value, you won't (you'd be better off buying a GREAT speaker, used off craigslist and flipping it for the same price later)

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Do you mean speakers or drivers? Those are drivers and they're only one part of a speaker. 

 

I would probably make TWO bookshelf speakers and space them reasonably far apart. This would be 2 drivers and the other 2 would go unused (unless you want to go the surround sound route and have 4 speakers total).

I would NOT try to create a crazy "sound bar" it'd have atrocious comb filtering. At a ton of different frequencies each of the drivers would be working against each other and canceling out the others' sound waves. The issues with "center channels" - which are not as bad as what you'd have - are listed here - 

https://www.youtube.com/watch?v=GZrdsxrcpBw&t=664s

If you want to simulate why 4 sources is a bad idea: 

https://www.falstad.com/ripple/

 

 

As far as making speakers... 

I'd try to find a commercial design with a single 3.5" driver and just copy it. For a first project, you'd probably want to do a sealed box instead of fiddling with port design. Unfortunately, in practice, at the same price you usually end up WORSE going the DIY route unless you're buying a kit (and even then those can be hit or miss). Commercial designs from manufacturers can get away with putting in $100,000+ worth of engineering into their designed and they get their parts cheaper than consumers. The average person doesn't have a strong physics/electrical engineering background, doesn't know how to design an enclosure and for multi-driver set ups, they don't know how to design a cross over network (I don't). There's a reason why DIY designs take FOREVER to sell on craigslist. 

If you can't find an existing design you can copy somewhere online, I'd GUESS (pulling this out of my rear) you'd want something like x 4" x 6" x5" as a box size. It need to be wide enough to fit the driver and generally NOT be a cube. 
 

12 hours ago, The Torrent said:

i want 1 box with 4 speakers in it.

WHY? No seriously, why do you want 4 drivers in a box? This is NOT a case where more drivers = more better. This is a case where more drivers = more problems. It's MUCH easier to make something with serious design issues. 

 

12 hours ago, The Torrent said:

I have also heard that cube boxes are bad and the driver should be different distances from each corner of a box. idk how this works or what i should do with this information.

I want to say, a cube with a single (or otherwise symmetrical array) driver would have multiple frequency reflections all coincide. You'd run into the risk of REALLY bad resonances/noise cancelations. At least this is what happens on the other end of things with bass (cubic rooms are bad)

I'm outside of my area of expertise, I decided I wasn't going to buy $50,000 worth of tools, $100k of software + throw hundreds of hours of time to try to save some (but not that much) cash on speakers. Same reason why people don't go the DIY route on satellites or CPUs (but much less extreme). Using the time and money saved I'm tossing it into a career doing machine learning. 

 

Quote

do i need to put a spacer internally in the box to seperate left and right?

should i put anything inside the box like foam or cotton for dampening?

does shape of the box matter?

these r the type of questions i have, not neccecarily volume.

If you care about sound quality - buy a kit if you're asking questions like this and insist on building. It can be a fun project if you have most of the potential downfalls taken care of for you. Great way to learn and gain experience. Someone else did the engineering (probably mimicking an existing, not bad design). 

https://www.daytonaudio.com/category/25/speaker-kits

 

 

 

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If you INSIST on going down the route you're going...

https://www.diyaudioandvideo.com/Guide/BuildSpeakerBox/

Note that they're assuming you do a 2 way design with a tweeter and a mid-woofer. You've got a tiny "full range" driver which is sorta like a low quality midwoofer that can do high frequencies as well. 

Here's a deeper guide... 
https://sound-au.com/articles/enclosures.htm

 

[geo3]

This is a bad idea, period. A full range driver, like a tweeter, should play by itself. Combining multiple will sound like crap.  Only when the driver is significantly smaller than the wavelength of the sound it's playing does it make sense to have more than one. 

 

The exception is when your are making a line source speaker, but you need a dozen or so per side for that to start to make sense. 

 

If I were you I would make 4 individual surrounds using those. 

[cmndr]

So NOT a perfect simulation but... this is kind of what happens if you have 4 woofers in a room.
You'll notice that there's places where it's EXTRA bright from the waves combining. There's also places where it's randomly dark from the waves canceling each other out. 

In this case there's not really a good place to go where you don't have a bunch of random cancelations. Moving just a little (and you have two ears) exposes you to a cancelation. 
This is JUST one frequency though. 

 

Here's the same thing with another frequency - Also bad. Also different locations are less bad. 

 

 

 

 

This is what you get with a single point source - yes there's reflections off the wall but if you're kind of near the center of the speaker, the sound will still be even and consistent instead of a jumbled mess. It'll also (not shown) be even and consistent at a wide range of frequencies, instead of being uneven in crazy different ways at slightly different frequencies. 

 

 

To add to that - there's benefits when it comes to doing stereo. You can tell WHERE a sound is left/right and front/back which is nice. You can't really get that with a single, bastardized mono speaker.