Need suggestions for my DIY project.

[arhantd]

I am looking to make my first DIY speaker.
Its going to be a 3 way open baffle speaker.

Drivers:

10'' woofer from Criterion 100b speakers. its 8 ohm, 40w.
I had these lying around, really old, they work very well.

I have got a pair of Peerless - 25mm Fabric Dome Tweeter - SR10DT
and a pair of Peerless - 5.25" High fidelity 8 Ohm woofer - SKO130
I ordered these and also pre-made 3 way crossover from DIYAudioCart.

Crossover:

3-way-5 inductor crossover - 900hz and 4000hz crossover points.

I still need to test whether everything works together nicely.

But i need help in deciding the most suitable open baffle design for this project. So anybody with some experience and knowledge can guide me here.

Also if you can suggest which material to use for the construction. MDF or Plywood and thickness?

I had thought of these two designs. One of them is fairly simple and the other one is better looking aesthetically. But i want build something that sounds good so need inputs.

Thanks for looking.

 

[Sumanta]

I have used mdf and am happy with it.
I will be following your thread from now on.

 

[arhantd]

Thanks. Even i am planning to you MDF ut just wanted suggestions whether something that is better for open baffle is easily available?

Also i am leaning towards the simpler design, just because its simple, but incase there is another suggestion or design that seems more appropriate please do chip in.
I still have a couple of days before i begin.

 

[bibin3210]

Using MDF alone for the first design is not advisable. Over a period of time MDF bends if it doesn't have proper support. You need to give some sort of bracing from back side. A minimum thickness of 1.5 inches will be good for the baffle.

May be you can try a combination of MDF and Plywood, 19mm MDF and 19mm Plywood where the MDF layer can be kept in front so that it will be easy to make the flush mounts.

Thanks,
Bibin

 

[soundnovice]

i have tried using 1" MDF for OB with 15" heavy woofer and its good. see if u can go for waterproof version which comparatively bit more heavy and denser than normal MDF.

 

[arhantd]

thanks a lot for your suggestions.

I have found a 6x4 19mm plywood board lying at my place. So i am thinking of using that.
no point buying another one.

As for design choice i will go with a modification of the first.
I want to give it a slight tilt but if i cant ill just build it straight.
Posting the two options below.

Should start with it today.

I hope its okay to build this with Plywood?

Thanks for the help.

 

[Sumanta]

My OB baffle of MDF is just 24inch made with 2 X 12 inch pasted together and it has one 15 inch and one 12 inch and is working fine for last 6 months or so....
Plywood works if it does not have blank spaces in between its plates.

I think your first post's 2nd option will work and look good with tapered upper end. Wider baffle reaching ground will increase SPL for low frequencies.

 

[arhantd]

Sorry for the late report.

The project is well underway.

I am attaching a few images and will look forward to suggestions. This is the first time
I am building a speaker so i dont expect it be that great but still its a fun project.
And hopefully i can improve it with some suggestions.

First off i experimented with the 10" driver from the old 100b speakers in Open baffle design.
I think they did quite well as full rangers themselves. I had read that on another froum about them so i gave it a try.

Back

This was purely an experiment. But the sound was quite nice and warm.

Later when my box was semi-finished.
I fitted all the three drivers and the crossover. Soldered the connections and gave it a spin.

I am using a vintage sansui au-222 amp to drive these. 40 w/ch.

Back

Well first i wanted to see if even it works, luckily sound did come out loud and clear from all three drivers.
So atleast that was nice.

But to my ears it was quite bright and it felt as if most of the sound was coming from the Tweeter.
Personally, i think i preferred the 10" driver in Full Range mode.

So i want suggestions on how to improve this?
Is it because the mid-woofer and tweeter are brand new and need break-in?
Hence they might mellow-down on their own?

Or is it something of a design issue that i can address?

Please help me out on this.

I plan to finish this in the next few days with a small pedestal, a bracing in the back, pretty much like the design on the paint image posted before. Then follow it up with laminate finish and some form of spikes/feet to rest on.


Thanks for looking.

 

[arhantd]

Somebody, any help please???

What i have done so far is to increase the width of the speaker by adding 4 inch (width) pieces from the bottom to a little over where the 10" woofer ends. This i have done on either side(kind of like wings), So hopefully that gives little weight to the lows.

Also i am planning on doing a couple of things to dampen the tweeter.
Use some material to stuff the sides of the tweeter and also the back?

Is that a good idea? I really need ideas to lessen the brightness of the tweeter and get a more balanced sound!
It still feels like majority of the sound is coming from the tweeter.
So someone please help.

The other thing i am planning to experiment with is screwing the Tweeter from the inside instead of outside.
Will that affect it in any way?

Thanks

 

[kapvin]

Somebody, any help please???

What i have done so far is to increase the width of the speaker by adding 4 inch (width) pieces from the bottom to a little over where the 10" woofer ends. This i have done on either side(kind of like wings), So hopefully that gives little weight to the lows.

Also i am planning on doing a couple of things to dampen the tweeter.
Use some material to stuff the sides of the tweeter and also the back?

Is that a good idea? I really need ideas to lessen the brightness of the tweeter and get a more balanced sound!
It still feels like majority of the sound is coming from the tweeter.
So someone please help.

The other thing i am planning to experiment with is screwing the Tweeter from the inside instead of outside.
Will that affect it in any way?

Thanks

firstly, congrats on your efforts. I have never had the guts to do an OB. so full points for courage!!

secondly, you need to read up a bit more. try diy audio. and read up on h frames and U frames.

there could be any number of reasons for your problems, could be different efficiencies of various speakers, miswiring, or simpy the the bass rolloff that the OB causes.

if all the rest is well and checked. you could look at doing a U frame to get a bit more extension.

the mid can handle a lot lower, so you could cross it over at say 200hz (in a u frame) or 300hz and then simply enclose your woofer. you get eh OB sound from 300hz on, and still have some bass..

but these suggestions are directional. please read; and feel free to ask.

 

[arhantd]

Sorry for the delay.

I have finally almost completed my speakers.

I say almost because i need to do some tweaks to get better bass. Its a little dry at the moment.

The overall sound is nice and clean. Much better than i had initially thought i would get.
I am running these with an Sansui au-222. Played around a bit with tone controls on it and am finally getting a really nice sound. the bass is a little dry and i am going to try a few modifications to improve that.

I am planning to try two things.

1) Insulate and Enclose the 10" driver. Luckily due to my frame design i can try that easily and i have some insulation material available. So will try that soon.

2) To add hinged planks on wither side of the 10" driver. I dont know how much difference will it make but might as well try.

Other than that i am very happy with the mids and highs and the vocals also sound good.
Atleast to my novice ears they seem to do alright for a first un-calculated attempt.

Sansui outputs 40 w/ch and its driving these speakers quite well and loud. Hosted a small outdoor party with these and they worked pretty well.
Currently i don't think they are good for critical listening but for casual listening and a party they do the job well.

 

[acoustics]

There is nothing as such a pre-built crossover or an off the shelf crossover.
Designs like yours require smartly designed crossovers. Just the look of that crossover tells that it has a bad design . Have a look at the inductor placement.
the inductors are so close to each other and their orientations are all the same.

measure an inductor
Re-measure it with just a screw besides it
Re measure it once again with another inductor besides it hyeah:

There is something called inductive coupling my friend

Your first step : Get rid of that crossover

I have seen a lot of people making speakers that just want to look like some real expensive ones, and i believe thats not the case here.
Who so ever put that crossover together lacks the very basic knowledge of crossovers.