First time 3-way speaker setup/crossover help.

[N10]

Hey guys,

I'm a first time builder looking for some help with designing a 3-way speaker system.

I've found the drivers i'd like to use, but I have no idea how compatible they are with one another and I also have no clue as to how to properly design a crossover. Any help would be appreciated!

The 3 drivers I have are as follows.

Tweeter: Dayton RS28A Aluminum Dome Tweeter
Mid: Dayton RS52AN-8 2" Dome Midrange
Woofer: Dayton ST305-8 12" Series II Woofer

They are all from Parts express and all the specs are listed there.

I'd really like to know if the setup I've picked out is something that would sound decent together. And more importantly, if the first part is true, then how would I go about making a crossover for it? Parts express had several prebuilt crossovers, but from what I've read, crossovers really need to be hand built for each specific setup, and that's where I get stuck.

Any help is much appreciated! Just be honest that's all I ask.
Thanks.

 

[Cal Weldon]

all the specs are listed there.

How about you provide us the links to save time.

 

[N10]

Links...sorry!

Here they are, sorry for not including them.

Tweeter: Dayton RS28A-4 1-1/8" Aluminum Dome Tweeter


Mid: Dayton RS52AN-8 2" Dome Midrange



Woofer: Dayton ST305-8 12" Series II Woofer

There they are linkwise. But to save more time I'll give you guys some specs for each, hopefully that'll save you from some time waste too.

Tweeter: 4 ohms impedance, frequency range 1600-20000 Hz.
Power handling 100 watts RMS/150 watts max.

Mid: 8 ohms impedance, Frequency range 500-7000 Hz.
Power handling 60 watts RMS/90 watts max.

Woofer: 8 ohms impedance, Frequency range 27-2000 Hz.
Power handling 275 watts RMS/380 watts max.

Those specs I wrote are probably too general, but I hope they help some, and if not, the links will point you to more detailed ones.

Here's the link to the crossover I was looking at as well, incase it was even worth looking at, but I'm pretty convinced i'll need to handbuild one now.

Crossover: Dayton XO3W-700/5.6K 3-Way Crossover 700/5,600 Hz

If there's anything else I need to include, let me know.

I do not have any cabinets built for this setup.

 

[MJL21193]

Hi,
You will get a bunch of "go with an established design" and "don't use a pre-made crossover" from others, so I won't go there.
The woofer looks ok, but you need to change the mid. The woofer will be best crossing well below 700Hz, and that mid you've picked doesn't go that low.

Have you done any enclosure modeling yet? I use Unibox for this and find the results to be accurate and dependable. Learning to use it properly can take some practice.
What are you thinking - vented or sealed. For that woofer, vented would probably be the best alignment.

Good luck with your project.

 

[Cal Weldon]

What he said.

 

[infinia]

Hi
If you already have the drivers you could shoot for an AR3 type of cloned design. Maybe use a smaller (non EBS) ported instead of sealed box. IMO could be really good sounding (not monitor quality) with the RS52 one the better mid domes out there.

edit> I think the woofer mid response looks shakey but it depends on the testing and your perspective, anyway FWIW a lot of people loved old school AR designs.

 

[N10]

What are you thinking - vented or sealed. For that woofer, vented would probably be the best alignment.

Good luck with your project.

Thanks for the feedback! I'll look for another mid and post back here...I'm glad the tweeter and woofer are compatible though...gives me somewhere to start.

As for enclosures, I was just sketching some things out, and I was planning on a vented one, although it's harder to do that way, I think I could manage it, just volume becomes more important then correct? Which prompts me to ask is it alright to use the manufacturers recommended volumes and just add them together for all 3 drivers to calculate the box volume?

 

[N10]

Other mid selections...

Here are some mids that would meet the below 700hz requirement.

1. Tang Band W3-1723SA coaxial midrange

2. Pioneer FB12EU14-51F midrange

3. Pyle Pro PDMR5

My only question about these is, does wattage really matter? The tang bend mid is only 10 watts RMS/20 watts max. The tweeter/woofer are each over 100 watts RMS. Should that be a problem? The other two are in a similar watt range so it's not an issue really there.

 

[MJL21193]

As for enclosures, I was just sketching some things out, and I was planning on a vented one, although it's harder to do that way, I think I could manage it, just volume becomes more important then correct? Which prompts me to ask is it alright to use the manufacturers recommended volumes and just add them together for all 3 drivers to calculate the box volume?

The mid will absolutely need to be in its own enclosure within the box, otherwise it will be (heavily ) influenced by the woofer.

The tweeter is sealed already and doesn't need this, or a volume to work in.

The mids you have picked still do not go low enough (also, the first one is a coax). You should be looking at a midwoofer that has good response down to 100Hz or less and up to ~5K. That woofer should cross around 300Hz.

 

[N10]

Alright...so something like the mids below would be optimal?

1. HiVi Mid/bass

2. Tang band midbass

3. 3" midrange


And again, is wattage something I should be considering as well?

If one of these will work then I know i'm on the right track as far as selections go, and I'll look into them more closely and make a final choice. Then it's just about the crossover. I'll scout around the forums more before I pester anyone more deeply for info on that.

Thanks for the insights! If it weren't for the feedback i'd have made several big mistakes!

 

[MJL21193]

The HiVi and TB look ok. Lower efficiency could work well if you use the woofers higher spl to get some baffle step compensation. Just to pad down the tweeter to match.

Power handling matters, but it's proportional. Half of the total power consumed is below 350Hz.
More important question is how powerful is the amp you have to drive these?

 

[N10]

It'd be a Harmon Kardon HK3490.

120w x2 channels.

Here's a link.

 

[MJL21193]

Here's a much better midrange for about the same price: Vifa P13

 

[N10]

Parts list....final i hope!

Alright, I'm going to take your advice on the mid there and stick with the original tweeter/woofer.

That means the final list will be

1. Tweeter
2. Mid (Vifa P13)
3. Woofer

Now, taking from your other posts, I should have a crossover point at 300 hz. for the woofer. I'm not sure how exactly you figured that out. Could you explain more?

Should the Tweeter cross over somewhere at 4000 hz? Is there overlap between the drivers that we're looking to get? Or is it driver dependent the amount of overlap?

Another question. What do the "orders" mean in the different types of crossovers... IE 1st order butterworth, 2nd order etc.... Should I choose one of these specifically, or is it a matter of personal preference?

Thanks for all the help, I hope I've not been to much of a pain with all these questions.

 

[MJL21193]

Well, looking at the response graph is semi-helpful, but these are usually not very accurate. I based that more on baffle step (look this up) where I'd assume for a 12" driver, you'd have a 15" wide baffle. This would correspond to ~300Hz baffle step.

Your mid-high crossover point for these drivers can be as high as 4K, but you may want to go a bit lower although I don't think I would.

Orders are the amount of attenuation per octave - 6db/octave, 12db/octave and so on. Butterworth, Bessel, Linkwitz Riley are alignments or types of crossover filters. Selection of the type and slope (order) is determined by the individual response of each driver and their combined response. This bears reading up on but like anything else in the realm of audio, the more you learn, the more ignorant you know you are. Generally, you can expect reasonable results from second order butterworth filters for these drivers.

Here's some light reading:
Baffle step

Here's a handy crossover calculator

 

[N10]

calculations.

Alright, now that i've got finalized parts, I put in the values for a crossover with your crossover calculator link. I may have input them wrong but here's what it spit out and what I put in to figure those things out.

Inputs: High pass impedance: 4 ohms
Low pass impedance: 8 ohms
Frequency: 300 Hz.

The outputs then were as follows.

C1: 93.75µF
L1: 3.001333333333333mH

C2: 46.875µF
L2: 6.002666666666666mH

Am I correct in that the "C1, C2" are referring to capacitors, and the "L1,L2" to inductors?

I wasn't sure if I should have input the frequency range of the woofer crossover (300 hz, like you suggested), that's where I thought I went wrong. And I may not have, I just don't know. Also it was only a 2-way crossover...is that the correct application for the 3-way speaker?

I downloaded Unibox and I have a few questions on how to use it.

Should I take the values for the woofer, tweeter and mid and add them to the Unibox database? Or should I only add one of them to the database?

Under Drive Unit configuration, should I select 3 drive unites in series or parallel? The program isn't very clear on some things, I don't exactly know where to start.

 

[djarchow]

The other poster said that he expected a lot of "don't do this" posts, but so far there aren't any. So here goes.

Designing a three way speaker (especially one that sounds good) is no small task for those with experience designing XOs and the tools and software to measure your own drivers frequency response in your enclosures. It sounds like you may be lacking on both of these counts. You will get much better results building an established design done by someone with the tools and design experience to get it right.

Second, XO calculuators like you linked to just don't work very well. They assume a resistive load instead of a loudspeaker which has a reactive load (changes with frequency). Not to mention that they don't take into account the drivers frequency response.

Here is the frequency response of a three way center channel design I did recently with well behaved paper drivers in red. Those same drivers with textbook values like the ones you were linking to are in blue. As you can see the frequency response of the textbook values system is terrible.

If you want to take up this hobby, start buying some books, software, tools etc as it is a great hobby. On the other hand, if you just want to build a speaker or two, you will be much better off using someone elses design.

Good luck,

Regards,

Dennis

PS Unibox is just for simulating the woofer or mid low frequency response in a box. It has nothing to do with XOs or tweeters

 

[MJL21193]

Re: calculations.

Under Drive Unit configuration, should I select 3 drive unites in series or parallel? The program isn't very clear on some things, I don't exactly know where to start.

First I need to apologize.I didn't notice that the tweeter is 4 ohm and you should think about getting an 8 ohm one.

Second, what are your expectations for this design? Like anything else, the more you know the better the results will be. As mentioned above, designing a good three way is not an easy task even for those that are well versed on this. You are starting to learn, so don't expect a masterpiece the first time. As for the established designs, you learn very little from doing one, you just end up with a facsimile of someone else's work. Will it sound good? Will it sound good to you?

On with the show.
You can do a pretty serviceable job with that calculator. No, it won't be perfect, but it will be a good start. You need to set 2 crossover points. One at 300 and one at 4k. The midrange will have a high-pass filter(above 300) and a low-pass filter(below 4k). The tweeter will have a high-pass only (4k) and the woofer will have a low-pass only(300).

Unibox will model the enclosure for the bass driver. That is it's purpose and it doesn't really handle the other two (although you could model an enclosure for the mid with it).
I will try to find time later to demonstrate it a bit.

 

[MJL21193]

Unibox.
First after you open the file is to enter the T/S specs of the bass driver you want to make a box for.
Resonant frequency - Fs, voice coil resistance - re, mechanical and electrical Q of the driver - Qms & Qes, cone area- Sd, equivalent volume of air that equals the suspension stiffness - VAS and linear excursion - Xmax.
I have put in the specs for the woofer you selected. In the middle column, you'll see some of the calculations that Unibox has done based on the T/S specs.
On the right you set the drive unit config box to single drive unit for a box with one woofer.

 

[MJL21193]

Here is an example of a vented box for this woofer. Box volume is 100 litres or about 3.6 cubic feet. This is a fairly large box, but it is nearly ideal for this driver. Response goes down to ~30Hz.

The vent would be a 4" pipe about 10" long.

This will easily handle the 120 watts that your receiver has without running out of Xmax - the cone movement is within it's normal range of back and forth motion.