Building your own three way speakers.

SPLaddict90

SPLaddict90

Audioholic Intern
for people who are are building their own speakers for their system, Have a few questions.
-what are you using for cross overs.
- are you using 3 way cross overs or individual hp filters,
- how are you wiring the 3/4 speakers to get an 8-6 ohm load.
- do you load ports off the wall?
- do you want driver and port on same plane,

any other tips would be nice, currently coming from a car audio background specifically SPL, my current build is going to be 2 tower speakers that are an old 3 way cabinet with a 12 inch woofer 5-1/4 mid and two spots for tweeters, I was planning on using parts express for the drivers looking into GRS and Dayton audio. the woofers are going to be cut at 80hz as I will be using two 15 inch subwoofer lpf at 80hz,
the center channel speaker I built is with 4 4-1/2 mid bass drivers and peerless tweeters
the surrounds are going to be old sony bookshelfs I have from an older hifi system from 2008
so just ideas really for the two tower speakers and how to integrate the 3/4 drivers best, also the receiver I will be using is a 7.2 and does have bi amping capabilities just not sure if I want to leave these two channels open for filling in areas not sure as I want it to be clear but I also like loud.


sorry for the ramble.
 
lovinthehd

lovinthehd

Audioholic Slumlord
First, more appropriate for the diy subforum here. Second, you're in way over your head already :) Putting together a speaker the way you're going about it will likely end up a mess (no offense, that's just the way it is), what might be called a frankenspeaker.

You're not planning on even designing your own box for the drivers' t/s parameters? I don't think you'll get any recommendations for an off-the-shelf crossover network here at all. You might consider going active crossover, tho. Overall I think you should study up on speaker design....something like Vance Dickason's Loudspeaker Design Cookbook.
 
ryanosaur

ryanosaur

Audioholic Ninja
Depending on your skill level, the four books I've seen on Speaker design, in order of accessibility:
Introduction to Loudspeaker Design, John Murphy
And:
Designing, Building and Testing Your Own Speaker System, David Weems
Then:
Speaker Building 201, Ray Alden
Then:
Loudspeaker Design Cookbook 7th Ed, Vance Dickason

The Alden and Dickason books really get into the meat of it all and can be dense without some foundation.

Beyond that, I agree with Lovin'. What you are talking about doing is a recipe for poor sounding speakers at best.

Dig into it and do it right! :)
 
SPLaddict90

SPLaddict90

Audioholic Intern
the woofer I am using is already matched to the internal box volume and the mid range and tweeters I am using are sealed back, as I took the measurements after my added bracing, the boxes I am using are really well built, and I have reinforced them and retuned them for the application. my question is really on how to cross them over the best. as far as the woofer it'll be in a 1.6 cube box with a 2-1/2 inch aero port tuned to have a flat response from 55 up to its cut off. according to my speakerbox app, like I said I am coming from a car audio background so im used to building highoutput enclosures for multiple woofers doing 155db and up at 35hz and below... so I know the approach is different with home audio.
 
SPLaddict90

SPLaddict90

Audioholic Intern
Depending on your skill level, the four books I've seen on Speaker design, in order of accessibility:
Introduction to Loudspeaker Design, John Murphy
And:
Designing, Building and Testing Your Own Speaker System, David Weems
Then:
Speaker Building 201, Ray Alden
Then:
Loudspeaker Design Cookbook 7th Ed, Vance Dickason

The Alden and Dickason books really get into the meat of it all and can be dense without some foundation.

Beyond that, I agree with Lovin'. What you are talking about doing is a recipe for poor sounding speakers at best.

Dig into it and do it right! :)
thanks for this information I will be reading this.
 
ryanosaur

ryanosaur

Audioholic Ninja
Please mind, I'm only still learning about this, myself.
Key things are that the individual drivers FRs overlap by a minimum of an octave... usually more depending on the type of roll-off you will employ (2nd order is -12dB per octave, 4th Order is -24dB per octave, for example).
You need your XO point to also be at least 1 Octave away from the drivers Break-up frequencies (more is better).

If your drivers are suitably matched, then you can begin designing the XO. Modeling programs are available for this, including the Bagby worksheet for Excel (which used to be free... may still be).

Without measurments, you are still whistling in the wind. Most drivers do not perform as shown in the spec sheets. Being able to test actual driver responses and T/S Parameters is necessary for good builds. These actual measurements will also effect the XO components.

123Toid has a series of YouTube vids on XO work. Maybe check those out and see what he's doing.
 
SPLaddict90

SPLaddict90

Audioholic Intern
thanks for the tip, yeah like I said I'm good with some of the box science its just obviously with subwoofers and in car audio were working with 1/4 wave theory and much more narrow band width and the crossovers come with the mids and highs so different world. but yes I plan on crossing drivers at 1 octave on 24db slope as that's how I have it set up in my currently found a pdf in the meantime of the loudspeaker cook book. thanks for the help guys the car audio forums are a lot more brutal and cut throat lol .
 
S

shadyJ

Speaker of the House
Home audio speaker design is very different than car audio speaker design. In car audio, you know exactly where the listening positions are, and they are all near-field but also spread out. Directivity control is not a concern with car audio. You can build a home audio speaker, and it can make sound, but you will be missing some important aspects of sound reproduction if you carry car audio loudspeaker design principles over into home audio.

I'm not saying to not do this, but I am saying don't expect your results to be on par with higher-fidelity designs. It will be a good experience to build a speaker though.
 
SPLaddict90

SPLaddict90

Audioholic Intern
I know they are completely different beasts which is why I asked for the material, but yes when it comes to Reflection and phasing that's where it starts getting new to me lol. but yeah hole point of using cheap no name drivers and an older cabinet is so I can experiment and see the differences. before I go in and building with good equipment. my first mistake in car audio was buying all the "best" name brand stuff then finding out there was better for my application.
 
everettT

everettT

Audioholic Ninja
I know they are completely different beasts which is why I asked for the material, but yes when it comes to Reflection and phasing that's where it starts getting new to me lol. but yeah hole point of using cheap no name drivers and an older cabinet is so I can experiment and see the differences. before I go in and building with good equipment. my first mistake in car audio was buying all the "best" name brand stuff then finding out there was better for my application.
Even though manufacturers provide the T/S parameters, they can vary (sometimes significantly) so if you get serious about doing your own designs, you will need a woofer tester to confirm measurements.

A measurement mic for test box

Software like BassBox Pro with crossover designer can aide greatly with design.

These are just some of the things needed along with the knowledge that's provided in the reading material to get started.
 
S

shadyJ

Speaker of the House
I know they are completely different beasts which is why I asked for the material, but yes when it comes to Reflection and phasing that's where it starts getting new to me lol. but yeah hole point of using cheap no name drivers and an older cabinet is so I can experiment and see the differences. before I go in and building with good equipment. my first mistake in car audio was buying all the "best" name brand stuff then finding out there was better for my application.
That's a good idea. You might want to start out experimenting with two-way designs instead of three-way designs as well. Much easier to model and assemble. Starting out with a three-way is very ambitious, unless you expect to fail.

A really good book that will show you good design goals is Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, 3rd Edition by Floyde Toole. One of the very best if not the very best books you can read if you are interested in High Fidelity Audio. I can't recommend this book enough. Audioholics did a review on it here.
 
ryanosaur

ryanosaur

Audioholic Ninja
A really good book that will show you good design goals is Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, 3rd Edition by Floyde Toole. One of the very best if not the very best books you can read if you are interested in High Fidelity Audio. I can't recommend this book enough. Audioholics did a review on it here.
Didn't know AH reviewed the book! I have it, but am still working my way through the Master Handbook of Acoustics 6th Ed. by Everest and Pohlmann. Eager to get into Toole.
Testing Loudspeakers by D'Appolito is after that.
 
Kingnoob

Kingnoob

Audioholic Chief
Home audio speaker design is very different than car audio speaker design. In car audio, you know exactly where the listening positions are, and they are all near-field but also spread out. Directivity control is not a concern with car audio. You can build a home audio speaker, and it can make sound, but you will be missing some important aspects of sound reproduction if you carry car audio loudspeaker design principles over into home audio.

I'm not saying to not do this, but I am saying don't expect your results to be on par with higher-fidelity designs. It will be a good experience to build a speaker though.
I can build a diy subwoofer but speaker design ehhh.. man it’s a really hard thing to do illl stick to buying speakers ...
Most I can do is replace the drivers in vintage speakers I don’t know how to recap or anything.\. ... could buy pre made x over but there too complex for me .
And when it comes to building the speaker .... too hard for my skills


Sent from my iPhone using Tapatalk
 
Pogre

Pogre

Audioholic Spartan
Hi SPL and welcome to the forums!

I think you're on the right track with the questions you're asking and reading your replies. I think at worst you will actually learn from this and probably do much better a second time around. It's refreshing to see someone pop in with a good attitude, open to advice and willing to learn. Good luck with your project!
 
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S

snakeeyes

Audioholic Ninja
There are also speaker kits you can build from places like Parts Express.
 
Swerd

Swerd

Audioholic Spartan
SPLaddict90, welcome to Audioholics.
My current build is going to be 2 tower speakers that are an old 3 way cabinet with a 12 inch woofer 5-1/4 mid and two spots for tweeters, I was planning on using parts express for the drivers looking into GRS and Dayton audio. the woofers are going to be cut at 80hz as I will be using two 15 inch subwoofer lpf at 80hz
Others (above) have already commented about your general plans. I agree with them, especially about the complexity of designing a crossover network for a 3-way speaker.

It might be worth the effort if you walk us through your thinking as you matched the 12" woofer to the cabinet you now have. Maybe you did it right and have nothing to worry about. And maybe not. I don't know how the car SPL guys design woofer boxes.

Once you're sure you have the cabinet right, you can begin to search for suitable mid range and tweeters. Pay close attention to the high frequency range for all your drivers. At what frequency does break up begin? Obviously, you want to avoid that. At what frequency do the woofer and mid range drivers loose off-axis loudness? When a driver's 45° off-axis performance drops 3 dB or more below the on-axis performance, the driver is said to begin beaming. This should be well below the driver's break up frequency. This is the frequency where you should consider making a crossover point. This is key to making a speaker have broad dispersion, and key to creating the impression of a 3 dimensional image of the musicians sitting in your room, not inside the speaker cabinet.

One last important point. Crossovers are best designed only after you have the drivers and measure their response vs. frequency AND impedance vs. frequency when mounted in their cabinet. Their impedance will vary across the frequency range. It is not a constant value. The crossover design software applications will take that measured data into account when coming up with a crossover. There are online calculators available, but most or all don't take variable impedance into the equation. They assume a constant impedance value, such as 8 or 4 ohms. Don't waste your time with them.

Your original post had several questions. You deserve some brief answers.
-what are you using for cross overs.
If you're asking about off-the-shelf vs. custom made crossovers, the answer is easy. Custom made is the only way to go.

You also mentioned a goal of 24 dB/octave crossover slopes. Learn (Google is your friend) about Linkwitz-Riley 4th order crossovers. LR4 crossovers will give the best chance of a flat frequency response (no dips, no peaks) across the crossover frequency range ±1 octave.
- are you using 3 way cross overs or individual hp filters,
Not sure what you're asking here. You should design individual high and low pass filters for each driver.
- how are you wiring the 3/4 speakers to get an 8-6 ohm load.
You mentioned one woofer, one mid range, and two tweeters, correct? Make your life easier, use only one tweeter. You gain little performance and lots of problems if you use two tweeters.

With 3 drivers, a woofer, mid range, and tweeter, questions of parallel or series wired drivers disappear.
- do you load ports off the wall?
Try to keep ports away from walls. In practice, this means keep a port at least as far away from a wall as the port diameter.
- do you want driver and port on same plane,
In my opinion, it works a bit better to have a port on the rear of the cabinet. A port on the front can work, but if it makes port noise (because the port diameter is too small), you'll notice it more if the port is on the front.
 
SPLaddict90

SPLaddict90

Audioholic Intern
thank you for the input on that and all the answers, the question with the crossovers is more because the crossovers we use in car audio are a lot different lol, as far as the box I used Bassbox pro for the driver and box and altered the internal dimensions by adding bracing until I had the freq response I wanted. but like you stated seems like the science is way different for home audio. so im not sure on what im gonna expect lol good thing the cabinets were free...
 
SPLaddict90

SPLaddict90

Audioholic Intern
Try to keep ports away from walls. In practice, this means keep a port at least as far away from a wall as the port diameter.
In my opinion, it works a bit better to have a port on the rear of the cabinet. A port on the front can work, but if it makes port noise (because the port diameter is too small), you'll notice it more if the port is on the front.
I tend to use areo ports and pretty sure port velocity laws are the same, I also was seaming to think of having the port on the separate plane would help with cancelation as well, when I was competing I gained 2.3db just from moving my port flare to the outside of the box separating the planes. now that im growing up I like stuff that sounds good and loud not just loud... but there is something about getting a good spl beating to the dome that ill never get sick of.
 

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