just got 4 separate eastech 9" subwoofers and am getting into audio. Have never built anything before but want to get these puppies pumpin. Was thinking of two basic sealed boxes. Is it too much to put all 4 in one box? Is BB plywood the material to use? How thick? I guess I need the amp/crossover controls. Where should I get the parts from? Any suggestions on what gear? I don't want to spend too much on the amp/controls as it's my first project but I also don't want to put in junk. How many watts should I be looking at for each box, round 100 to 300? And most importantly where can I find plans so I know what measurements to cut out? Pretty overwhelming to be honest but I'm sure once I get going I'll be fine.
Cheers~
Cheers~
Hi,
I'll try and go right to the basics here, but forgive me if I cover some stuff you already know.
All loudspeaker drivers have a series of numbers associated with them called Thiele Small parameters. These parameters allow us to simulate a given loudspeaker in any cabinet. There's plenty of free software about to do this - I'd recommend WinISD Pro.
At this point, you don't need to understand exactly what each of the parameters mean, but it'd be useful to have the parameters of your drivers. Emailing the manufacturer would be your best bet. If that fails, perhaps there's someone nearby that can measure them for you. You could also post pictures of the drivers, to see if anyone recognises them - they might be a buyout from another manufacturer.
When it comes to subwoofers, heavier enclosures (ie, thick material, include bracing - see first picture) are best, as they have more inertia. This will help to prevent the cabinet vibrating along, which would lose some (though not much) LF energy.
18mm (or 25mm) BB ply is the right material to use, but it's also expensive. Measure twice, cut once.
Depending on your location, there are lots of suppliers people can recommend - tell us where you are in the world and you'll get more help.
If you're buying from Parts Express, take a look here
Subwoofer Amplifiers, Plate Amplifiers, Home Audio/Video Subwoofer Amplifiers, Powered Subwoofer Amplifiers Perfect for Building Your Own Powered Subwoofer.
I'd say go for around 500w total. That's ~125w per driver. You're unlikely to cook them with that much power, but there should be plenty of output.
Hope this has helped
Chris
I'll try and go right to the basics here, but forgive me if I cover some stuff you already know.
All loudspeaker drivers have a series of numbers associated with them called Thiele Small parameters. These parameters allow us to simulate a given loudspeaker in any cabinet. There's plenty of free software about to do this - I'd recommend WinISD Pro.
At this point, you don't need to understand exactly what each of the parameters mean, but it'd be useful to have the parameters of your drivers. Emailing the manufacturer would be your best bet. If that fails, perhaps there's someone nearby that can measure them for you. You could also post pictures of the drivers, to see if anyone recognises them - they might be a buyout from another manufacturer.
When it comes to subwoofers, heavier enclosures (ie, thick material, include bracing - see first picture) are best, as they have more inertia. This will help to prevent the cabinet vibrating along, which would lose some (though not much) LF energy.
18mm (or 25mm) BB ply is the right material to use, but it's also expensive. Measure twice, cut once.
Depending on your location, there are lots of suppliers people can recommend - tell us where you are in the world and you'll get more help.
If you're buying from Parts Express, take a look here
Subwoofer Amplifiers, Plate Amplifiers, Home Audio/Video Subwoofer Amplifiers, Powered Subwoofer Amplifiers Perfect for Building Your Own Powered Subwoofer.
I'd say go for around 500w total. That's ~125w per driver. You're unlikely to cook them with that much power, but there should be plenty of output.
Hope this has helped
Chris
Here's my take on the "blown" woofer thing.
Since you are new to the whole thing do yourself a favor and drop say a little money on a used woofer, quality is unimportant because your going to destroy it.
Hook it up to an amp and play some test tones through it.
60hz, 250hz, 500hz, and 1k are probably good, download a test tone app if you have a smartphone. Theres lots of test/setup cds as well, second hand stores have them cheap.
What you are listening for is called clipping, its where the nice round sine wave gets too big for the amp and the amp "clips" off the tops and bottoms of the signal.
These flat tops and bottoms sound different and are actually Direct Current being sent to your speakers.
SPEAKERS DONT LIKE DC!!!
It heats them up, melts the glue that holds the voicecoil together and destroys them.
So what you do is play the tones, get used to the sound they make as they clip and then you'll know when to stop with the volume knob.
Now, just for kicks, turn the volume up to clipping on this speaker and keep it there. As the DC warms the coil and the glue melts it will smell.
That smell will be etched into your brain forever.
Keep it going, the speaker will smoke and the sound may get jangley.
The voice coil has left the former and the speaker is blown.
You have just "blown" a speaker, and might have done it with less than 10 watts.
I've seen 1000 watt subwoofers destroyed this way on a 35watt stereo reciever, when we demoed that same sub on a confirmed 2300 watt output amp.
A good source for a spekaer for this test is a local car stereo install bay, ask them for any oem/stock speakers they pulled out to replace with aftermarket, i got 2 pair for free just by asking.
Oh ya, i reccomend doing the smoke demo outside, the smell lingers for days.
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Thanks guys. I was hoping not to get too technical and just work on the woodworking skills and just wanted to buy the amp/crossover thing and get some basic measurements n plans and get cutting. Not really ready for testing parameters etc. quite yet. The subs are used. I have two of each below.
Eastech
4 ohms, Nom: 35W
PSD823580-0401
A248
Eastech
4 ohms, Nom: 35W
PSD823580-0401
A302
Eastech
4 ohms, Nom: 35W
PSD823580-0401
A248
Eastech
4 ohms, Nom: 35W
PSD823580-0401
A302
wow cool thanks Dave! I think Jesse is off the island (Alert Bay) for a bit but I'll catch up with him soon. I sure got spooked when you addressed the email to me but then it clicked as Jesse mentioned you and I checked out the gorgeous bamboo speakers you made. When you have time send me an email to tonoadams@gmail.com
thanks again~
Tono
thanks again~
Tono
Chris made Jesse's speaker... R2D2 above. They are strikingly pretty aren't they.
I understand Tono has just moved to Alert Bay so will have seen the real things before he saw the picture. Drivers have been upgraded since these pictures.
He has 4 of the woofers you used in your son's subwoofer.
dave
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