Active modular 3 way shared design?

[webby]

Is anyone else looking for their 1st active project?
How about a Modular 3 way shared design. What I mean is a system with the same tweeter and mid combined with a bass module depending on the size of room / requirements.
going active is daunting, and I want to remove as many of the mistakes as possible.
A shared design & configuration would remove a lot of the guesswork.

I don't have the overall budget for something like John K's Nao Note sleakers, otherwise that would be my first choice.

I am following the Freedsp 2 thread, and its very near finished and begging for a project. Hopefully it will cost a lot less that the mini DSP 8 channel. It uses Sigma studio, I had a quick look and Sigma appears more complicated than MiniDSP? I have a UMIK-1 measurement mic and have just started using REW.

Having a low cost design with the same amps, psu, speaker system would be very appealing. . A baseline crossover config to load would be a huge benefit, then use the room correction or REW to measure and adjust for each users room. We could share measurements and configs and design changes etc.

If we set a budget of up to $50ish per driver, up to $200 per speaker, should give a wide choice.*
An example might be;

Open Baffle for Tweeter & Mid, sat on top of Z baffle bass unit.

Amps could be TD3251d2; 1 chip in 4 x se for mid & tweeter and 1 chip for bass.

Or 3 x TDTPA3116D2 etc.
SMPS PSU.

Use best suited Ohm drivers for amp output

What about Dayton ND tweeter, this one has a wave guide;
Dayton Audio ND25FW-4 1" Soft Dome Neodymium Tweeter with Waveguide 4 Ohm *$20 x2 = $40

Or an AMT / Ribbon on top of the Vifa etc.

Vifa mid
Tymphany TG9FD-10-04 3-1/2" Glass Fiber Cone Full Range *$20 x2 = $40

GRS 15” woofer x 4 $100
GRS 15PF-8 15" Paper Cone Foam Surround Woofer

Drivers $180 ish

Anyone interested in a project like this?
This is the direction I am hoping to go in.

Ian.

 

[ewollowe]

Good idea, not sure if something like it exists already?

I'm interested in going active eventually but probably more of a FAST arrangement.

Curious to see how you go.

I'm off to investigate freedsp 2 now

 

[webby]

I did look before posting, there are some projects, but a shared group design i couldn't find.
I have no design skills, just a couple of speaker and amp builds to my name.
But the knowledge on this site is incredible, imagine what could be done as a group.
A well thought out design using reasonable cost drivers and Class D amps could make for great performance, flexible and tuned for each individual environment.

Just in case you missed the Freedsp 2 thread;
http://www.diyaudio.com/forums/digi...reedsp-v2-0-adau1452-developement-thread.html

Cheers
Ian

 

[Charles Darwin]

With twin 15 woofers I'd prefer a larger midrange then 3.5".

This one is cheap&cheerful, a bit more than the Vifa but still within budget I think:
FaitalPRO 5FE120 8ohm 5 80watt PA Speaker

They are a bit more expensive in North America though.
FaitalPRO 5FE120 5" Professional Midbass Midrange Woofer 8 Ohm

Also there is the identical looking model 5FE100 for a pound less but it loses the demodulation and the published FR gets a bit ragged roughly where you'd want cross it to the tweeter.

 

[LineSource]

Matches your goals: (White 2-cabinet TM-W)

10" Woofer FloorStander 3-way
3 - SB Acoustics drivers =$250
SB Acoustics :: 1.15" SB29RDC-C000-4 $52
SB Acoustics :: 6" SB17NRXC35-8 $58
SB Acoustics :: 10'' SB29NRX75-6 $140

Sealed SB17NRXC35-8 6" midbass has Qtc~0.7 in ~0.5cuft with F3~70Hz, and works well with a 1600-1800Hz crossover. (use LR4 with active). If customer desires ported option, they can start with a 0.82cuft ported cabinet tuned to 38Hz (2" dia, 6" long), and later put in a port plug which reduces the internal volume to ~ 0.5cuft.

There are passive TM crossovers available for SB29RDC + SB17NRXC35 if only 2-amplifier channels are available, and the active Xover is used mainly for complex room-bass-equalization.

---
Sealed SB29NRX75-6 10" woofer has Qtc~0.7 in 1.3cuft with F3~43Hs. A Linkwitz Transform can push this to F3~20Hz with modest power boost. A sealed woofer both sounds best, and is easiest to compensate for room effects. In a ported 2.3cuft cabinet(3" dia. 13.2" long), the SB29NRX75-6 produces Fs~24Hz deep bass.

---If you feel the urge to Build BIG..
Peavey 18" LoRider woofers are $200 each and very musical...
but now you need a 12" midbass to keep up...
but now you need a horn tweeter to keep up...
but now you have a different thread

 

[ActiveLin]

I'd be interested -> do requirements match?

I consider building a compact 3way dual purpose speaker for high end stereo+home cinema Fronts. Size about 16in. high, 9 in. wide and 12 in. deep, closed box for maximum control.

My supposed price range malmost matches yours , personal requirements:
- Digital crossover
- All cheap electronics, ready made products, no soldering, e.g. DCX crossover, low cost 4ch PA amps (600$ total)
- explosive speed in all frequency areas
- all chassis shall have similar properties concerning quality, sound radiation, speed, design.
- maximum feasible control and minimum feasible distortion
- wide radiation, so even 5 people watching a movie will be good positioned
- loud enough to support even the most demanding action movies (target: 110 db, sensitivity approx. 90db+)
- exceptional P/V, sound quality at a level where 3x the budget would be required to improve it. Chassis budget approx. 500$ (R+L)
- exceptional design, radically oriented at "form follows function". Clear shape &lines. Material & shape at discretion of each owner.
- very fast response, control over deep bass : rigid membrane for all chassis
- modular design, 3way box until 80Hz only, any deeper would require subwoofer modules (to skip for those who already have)

A possible combination:
- 1'' metal or ceramic tweeter
- 2'' metal dome mid driver, e.g. dayton RS 52 AN
- 8'' glass fiber/carbon/kevlar bass, e.e.g. scan speak

 

[webby]

Thanks for the replies.
I think simple construction should be a goal, to make the project more accessible. I have built open baffles and H frames in the past. You can get away with my level of woodworking, poor!
I like the look of the Troels designs, the cabinets look serious and require more skills / equipment then I have.
Open Baffle for Tweeter & Mid, small triangular baffle with two driver holes should be easy for most people.
Z baffle bass unit, I haven't built one, looks like slightly more difficult H frame. Adding a Karlson aperture could be done to aid dispersion, would add a little more work.
I don't want to aim for target specs, as it gets expensive. I would like to see good budget drivers, used to their best and tuned for each users home. I think the sound quality could be a lot better than most people (including me) are used to.
What do you think?

Cheers
Ian