need crossover for first time 3.5way build.

[mrc6064]

ok so i built some speaker cabinets with 16mm thick MDF. screwed it all together and now i want to build/buy a crossover... the cabinets will have 1x vifa tweeter 6ohms, 1x 6.5inch peerless mid range 6 ohms and 2x 12inch DA woofers. i dont know the specs of the woofers. except that they are 8ohms each. i do have the model numbers of the tweeter and midrange. basically what i want to know is should i get a 3 way crossover and wire my woofers in parralel or get a 3.5way crossover. my amp can handle 4ohm loads also.

[mickeymoose]

"Multi Way" in the speakers forum above.

Having missmatching speaker impedances and little or no info on the drivers I would suggest using an active xover. Use your main power amp for the woofers (at 4 Ohm) and a second amp with passive xover for the mid and hi. E

[DavidL]

How NOT to build a speaker is how I see your attempt. You can't just buy several drivers, build a cabinet and throw in a premade crossover and make it sound good.
MAYBE the cabinet size will work with your woofers but then again you didn't measure any T/S parameters , you have no FRD or ZMA files for the drivers and probably no equipment to measure anything is my guess. Finding someone willing to design a workable crossover for you and hold your hand to make this "creature" sound good is more than most will want to do for you.
Have you read anything about what it takes to design a complete system? Why didn't you first build a speaker that's already been designed? There are plenty on the web that would meet your wants and needs. If this sounds harsh, I'm sorry but it's just the honest truth and I'm trying to save you from endless hours of "why doesn't this work?". Either be willing to learn what it takes to build a good speaker and be willing to invest in the measuring equipment or just build a proven design.

[tinitus]

I'm mostly worried about box being too small for two 12" woofers

but you could try and connect the woofers directly to amp first, without any Xover
woofers only, and no other drivers

[mickeymoose]

If the tweeter and mid have open backs make sure to build an enclosure inside the box for them. E

[Jay]

Originally Posted by mrc6064

ok so i built some speaker cabinets with 16mm thick MDF. screwed it all together and now i want to build/buy a crossover... the cabinets will have 1x vifa tweeter 6ohms, 1x 6.5inch peerless mid range 6 ohms and 2x 12inch DA woofers. i dont know the specs of the woofers. except that they are 8ohms each. i do have the model numbers of the tweeter and midrange. basically what i want to know is should i get a 3 way crossover and wire my woofers in parralel or get a 3.5way crossover. my amp can handle 4ohm loads also.

1) Search for speaker projects using drivers that you have. You can "learn" a bit from the sample crossovers (and boxes). Ready made crossover usually has a high cut-off for the mid (high pass). This is NOT GOOD as you will waste your good midrange (I assume your 6.5" Peerless is midwoofer). And usually the midrange has peaks that is not addresses by ready-made crossovers.

2) Using the drivers specs (mid and tweeter) you can search and/or ask for the FRD/ZMA files. Then anyone will be able to help you to design the crossover (I think somebody is offering such service on the net) as it is not that difficult (2-way sealed). The result without actually "hear" the crossover (only computer simulation) will not be magical, but it will work and be much much better than using a ready-made crossover.

3) The 2-way must be sealed if you want to integrate the woofers (and because you have decided the size of the mid enclosure before calculation). The lowest frequency roll off of the 2-way will be made 2nd order LR. Later the crossover for the woofer will be decided (active or passive 2nd order LR).

4) I can see that you have separate boxes for each of the woofers. They seems to have the same size, so it seems it is better if both of them work at the same frequency range (with 8 ohm it will be better in parallel), and make them sealed (as you don't have a calculated box size, unless you want to measure the driver, which seems impossible).

Will the enclosure work? The size looks too small, but it might work, depends on the woofer specs. Your woofers seem to be a "cheap" low wattage one with small magnet. This is good, as the chance to work with smaller enclosure is high. By pushing the cone actually you will be able to predict if it may work. "Soft" resistance means good.

5) After you calculate the 2nd order LR for the woofers, you can "hope" they will sound good. If they don't sound good, you can go active, or build bigger enclosure for the woofers.

6) You can increase the size of the woofer enclosures by adding extra depth to the box, and make openings behind woofers' enclosures. Another option is you can add extra enclosure for one woofer with double the size. But you will have to close one of the previous hole/openings as you will use the previous enclosures for one woofer only.

7) Speaker design is not an easy task that can be done by a newbie, but I have found that newbies do not have extreme quality requirements. Many have been satisfied even with ready-made crossovers. So don't worry

[DavidL]

4) I disagree, small magnets and cheap drivers usually means a high QT and a large sealed box.

7) That's being pretty rude.....I would think he wants quality and a premade crossover will never work with random drivers.

He's better off with a proven design, less fuss and headache.

[Jay]

Originally Posted by DavidL

4) I disagree, small magnets and cheap drivers usually means a high QT and a large sealed box.

Yes, you're right, may be my mistake. I was and am confused also hehe. I was not trying to say that "with high Qts it is better with small box than big box" but I was trying to say that "with high Qts and small box it is better with sealed than ported".

Or, with other logic, you have a small box, you have a high Qts woofer, then you will probably have less problem with sealed than ported

Anyway, with such a small box (and presumably high Qts woofer) it is better to try sealed, if there is too much a "boombox" sound, or if the bass cannot go low enough, then increase the box size (e.g. up to twice as suggested previously). If still has the same problem, and you don't want to increase box size too much, then make a hole and buy some ports. Experiment with various port lengths. Of course I'm not suggesting others to do this (but I can do that). What else can you do? Go active of course.

Originally Posted by DavidL

7) That's being pretty rude.....I would think he wants quality and a premade crossover will never work with random drivers. He's better off with a proven design, less fuss and headache.

But he has bought the drivers and built the box. Teaching him to measure the woofer and buy the tools and the software is not feasible. He might be able to build one and sell them to friends, then buy new drivers to build a proven design.

I was not being rude (I told him that even with my "crazy" method of building the speaker, the result will be much much better than using a ready-made crossover. Just don't expect a magical speaker). I was actually trying to be worse . What I mean is, not just those who has never built a speaker, but many do not have an extreme standard for speaker quality. Believe it or not.

Add/Edit: It is because this low standard (or inability to perceive sound quality), many people keep trying to use ready made crossover, keep trying to build "unproven" design, and confused with the so many designs out there. Many newbies in this forum ask for a good DIY design, after the expert suggest a wonderful design, they still cannot "understand" and build something else instead. They think all speakers sound the same!

[Moondog55]

Seeing as you have already built the boxes I am guessing you really need some help to make the best of what you have.

The Vifa tweeter (D26 ) is well known if not universally liked and most peerless drivers are OK to very good but that really isn't enough.
We can "Try" and help a little but we need you to give us links to the drivers you have chosen or ALL of the driver information you have on hand.
The advice to go active is really the best option with a cheap electronic divider ( Cheap?? Behringer BEHRINGER: CX2310 )

Then get a second amp for the top end and develop a passive crossover for the top at around 2500 / 3000

[PeteMcK]

I'd go 2.5 way unless you intend to play these at high levels, then I'd go 3 way.
What are the model numbers? & what is the internal volume of the box you made?