Abyss Bookshelf speakers

[Minkeyman]

This is the first project I built so I decided to use pre-made enclosures instead of making my own. I used the Dayton .50 cu ft enclosures, a Dayton crossover at 2,500 Hz, the HiVi SD 1.1 tweeter and the HiVi M6N driver. I love the sound of these. The highs are crisp and clear and the M6's offer good bass. I used a 4" long by 1" port, which tunes it to around 52 Hz. The mids can get just a tad harsh when played loud but that's only on certain songs. Overall I love 'em and will definitely be using HiVi again!

[spasticteapot]

Re: Abyss Bookshelf speakers

This is the first project I built so I decided to use pre-made enclosures instead of making my own. I used the Dayton .50 cu ft enclosures, a Dayton crossover at 2,500 Hz, the HiVi SD 1.1 tweeter and the HiVi M6N driver. I love the sound of these. The highs are crisp and clear and the M6's offer good bass. I used a 4" long by 1" port, which tunes it to around 52 Hz. The mids can get just a tad harsh when played loud but that's only on certain songs. Overall I love 'em and will definitely be using HiVi again!

You really need an appropriate crossover. I'm not much good at PCD, but there's plenty of folks who can help you finagle something appropriate.

[johnlinvell]

Re: Abyss Bookshelf speakers

They look very nice....The first one is well you know as i'm sure your feeling it.

[Chris Roemer]

Re: Abyss Bookshelf speakers

This is the first project I built so I decided to use pre-made enclosures instead of making my own. I used the Dayton .50 cu ft enclosures, a Dayton crossover at 2,500 Hz, the HiVi SD 1.1 tweeter and the HiVi M6N driver. I love the sound of these. The highs are crisp and clear and the M6's offer good bass. I used a 4" long by 1" port, which tunes it to around 52 Hz. The mids can get just a tad harsh when played loud but that's only on certain songs. Overall I love 'em and will definitely be using HiVi again!

A 0.50cf box, and a 1"dia. x 4" vent, don't jive with a box tuning of 52Hz.

For a 0.50cf box, a TWO INCH dia. x 4" vent tunes the box to 56Hz, which is high for that combo.

A 1"d x 4" vent tunes the box to 30Hz, which is actually killing the bass.

A 1.5"d x 4" vent will tune the box to 43Hz, which should play down to about 50 cycles. That's what I'd use in THAT box.

But, I'd have gone with the 0.75cf box, probably, using a 2"d x 5" vent, tuning the box to 42Hz, and netting an F3 near 40.

A metal coned driver like that, usually "rings" higher up, where you don't want to hear it, THAT one rings at 4k, and is likely not being attenuated by your stock XO. This is probably your "harsh" mids you're hearing sometimes. A Zobel and notch filter could help. Also, that tweeter is +3dB louder than that woofer, so, typically a series resistor or an L-pad would be used to cut it down by about 6dB.

If you can tell me exactly what parts (caps, coils, (& resistors - if any)) are on that XO, I could look at it for you.

Chris

[Minkeyman]

Re: Abyss Bookshelf speakers

Thanks guys. I have a 3 ohm resistor on the tweets that keeps them tamed down. The crossover is this one: http://www.parts-express.com/pe/show...number=260-142

[Minkeyman]

Re: Abyss Bookshelf speakers

Where are you getting the formulas for these calculations? I used the formulas and charts I have in a speaker building book and apparently it didn't give me the correct answers. Do you guys have any recommendations on books with the formulas in them or formula lists so I can calculate this without relying on those stinkin' charts? lol. Thanks for the input guys!

[Paul Carmody]

Re: Abyss Bookshelf speakers

Well, if you "get" what the books are talking about, then the giant quantum leap forward is to use computer simulation. There are lots of programs out there to help you do this. One of the best and cheapest (free!) ones is Jeff Bagby's Passive Crossover Designer. By playing with values, you can instantly see the change in Frequency Response.

http://audio.claub.net/software/jbabgy/jbagby.html

You will need to bring in the Frequency Response and Impedance measurements of your drivers to these programs, though. Thankfully, HiVi's graphs are very accurate and you can trace them and get very high-quality results.
More info on that here

https://sites.google.com/site/undefinition/simulated-measurements

Also, I hate to be a stinker, but your port diameter is too small for that size woofer.

[Minkeyman]

Re: Abyss Bookshelf speakers

Ok thanks. I get what It's talking about but don't have any software to do the measurements and calcs for me so I was relying on the book's method. Thanks for the links! That'll help a lot! yeah someone else said that so I think its time to put the 1.5" diameter in. I used the book to get the port diameter and that's where I got the error again I think.

[Chris Roemer]

Re: Abyss Bookshelf speakers

Where are you getting the formulas for these calculations? I used the formulas and charts I have in a speaker building book and apparently it didn't give me the correct answers. Do you guys have any recommendations on books with the formulas in them or formula lists so I can calculate this without relying on those stinkin' charts? lol. Thanks for the input guys!

You can model a woofer/box response using the free WinISD from www.linearteam.org . Start off with the "beta" (non-Pro) version.

For XO design, software is used that uses your drivers' actual response (.frd) and impedance (.zma) profiles.

This plot shows a raw M6N, showing the metal cone "ringing" at 4kHz.

The red plot is your current response using your stock "textbook" low pass filter with the 1mH series coil and 4uF of shunt cap. Notice how the woofer is rolling off (-6dB) at 4.6k, NOT at your XO's advertised 2.5kHz. That stock XO WOULD roll off (cross over) near 2.5k IF your drivers had "flat" impedance curves (which moving coil transducers do NOT have) AND if their response curves were flat, which most drivers also do not have.

By simply adding a tiny 1.0uF cap (you COULD use a cheap npe cap, but use Dayton's 027-410 "poly" cap instead), we can force that breakup down so it's not as noticeable. This value needs to be pretty much spot on 'cause we're creating an impedance spike at 5kHz that will "kill" that 4k resonance, giving you the much better behaved orange curve. This cap goes in parallel with the 1mH coil on the woofer's circuit.

Chris

[Wolf]

Re: Abyss Bookshelf speakers

You can model a woofer/box response using the free WinISD from www.linearteam.org . Start off with the "beta" (non-Pro) version.

For XO design, software is used that uses your drivers' actual response (.frd) and impedance (.zma) profiles.

This plot shows a raw M6N, showing the metal cone "ringing" at 4kHz.

The red plot is your current response using your stock "textbook" low pass filter with the 1mH series coil and 4uF of shunt cap. Notice how the woofer is rolling off (-6dB) at 4.6k, NOT at your XO's advertised 2.5kHz. That stock XO WOULD roll off (cross over) near 2.5k IF your drivers had "flat" impedance curves (which moving coil transducers do NOT have) AND if their response curves were flat, which most drivers also do not have.

By simply adding a tiny 1.0uF cap (you COULD use a cheap npe cap, but use Dayton's 027-410 "poly" cap instead), we can force that breakup down so it's not as noticeable. This value needs to be pretty much spot on 'cause we're creating an impedance spike at 5kHz that will "kill" that 4k resonance, giving you the much better behaved orange curve. This cap goes in parallel with the 1mH coil on the woofer's circuit.

Chris

Don't forget a 4 ohm resistor in series with that 1.0uF cap, Chris! This is to avoid impedance shorts at ultrasonic frequencies.
Later,
Wolf

[Chris Roemer]

Re: Abyss Bookshelf speakers

Don't forget a 4 ohm resistor in series with that 1.0uF cap, Chris! This is to avoid impedance shorts at ultrasonic frequencies.
Later,
Wolf

Ben, would a 5w be OK? I wouldn;t want to break a budget ;-)

[Wolf]

Re: Abyss Bookshelf speakers

Ben, would a 5w be OK? I wouldn;t want to break a budget ;-)

I think I would go for a 10W, being function and placement is probably going to run some current.
Later,
Wolf

[Minkeyman]

Re: Abyss Bookshelf speakers

Thanks for the help guys. These programs are going to be super helpful on my next design. Now I've gotta try to learn how to use them between homework and classes. Will WinISD or any of the others help with box design for a box with 2 drivers?

[Chris Roemer]

Re: Abyss Bookshelf speakers

Thanks for the help guys. These programs are going to be super helpful on my next design. Now I've gotta try to learn how to use them between homework and classes. Will WinISD or any of the others help with box design for a box with 2 drivers?

ya

[Minkeyman]

Re: Abyss Bookshelf speakers

Cool. Thanks man