sony buyout

[nottaway]

Re: sony buyout

yep, about. I should check the wiring tho because 4 drivers parallel would give about 2 ohms and 3 sets should add up to roughly 6 ohms not 8.

Do you have a tweeter in mind or is it too soon since you havent measured response?

[r-carpenter]

Re: sony buyout

I have a few tweeters laying around. Played a bit with Vifa DX25 today. Have some ideas but it's too early. I'll need to lay the array horizontally and lift it up at list 4ft of the ground to get away from boundaries. Other wise the gating is laughably small. Also, remember guys, my array is an open back.

[XtremeRevolution]

Re: sony buyout

I have a few tweeters laying around. Played a bit with Vifa DX25 today. Have some ideas but it's too early. I'll need to lay the array horizontally and lift it up at list 4ft of the ground to get away from boundaries. Other wise the gating is laughably small. Also, remember guys, my array is an open back.

How will this change the frequency response measurement?

[r-carpenter]

Re: sony buyout

let me refer you to Music and Design

http://www.musicanddesign.com/tech.html

If I have enough time, I'll throw together MDF box to make a monopole speaker. You just need to decide on the volume.

[XtremeRevolution]

Re: sony buyout

let me refer you to Music and Design

http://www.musicanddesign.com/tech.html

If I have enough time, I'll throw together MDF box to make a monopole speaker. You just need to decide on the volume.

I was kind of hoping for a simple answer, not needing to spend a couple of hours learning the conceptual application of dipoles to answer the question myself, lol. Not that I don't need to, but the intention of my question was to figure out if what you do produce would be suitable for a closed box line array.

Any particular reason why you chose a dipole design?

[r-carpenter]

Re: sony buyout

I was kind of hoping for a simple answer, not needing to spend a couple of hours learning the conceptual application of dipoles to answer the question myself, lol. Not that I don't need to, but the intention of my question was to figure out if what you do produce would be suitable for a closed box line array.

Any particular reason why you chose a dipole design?

Qts of a driver is very high. In a small box it'll have a lumpy raised bottom end and with a general response roll off of a line array towards high frequency it'll be difficult to blend with the tweeter. Plus, I've played enough with "boxed" arrays and wanted to experiment with dipole.
In an acoustic suspension, you are choosing the volume behind the driver to adjust the roll off and control the bass extension as well as power handling/excursion. Not the same as dipole or open baffle. Look at the objective and capabilities of the Sony. I'd say if you can bring it to work nice through upper base in to mid range, fairly flat, great!
Model the Sony in any box modeling software package and see the roll off, the decide the volume.
At this point I am pretty confident, I can make it sound quite nice. Not nearly the same as my XJ92 line array but never the less, nice. And with all "life size like" benefits of line array.

[XtremeRevolution]

Re: sony buyout

Qts of a driver is very high. In a small box it'll have a lumpy raised bottom end and with a general response roll off of a line array towards high frequency it'll be difficult to blend with the tweeter. Plus, I've played enough with "boxed" arrays and wanted to experiment with dipole.
In an acoustic suspension, you are choosing the volume behind the driver to adjust the roll off and control the bass extension as well as power handling/excursion. Not the same as dipole or open baffle. Look at the objective and capabilities of the Sony. I'd say if you can bring it to work nice through upper base in to mid range, fairly flat, great!
Model the Sony in any box modeling software package and see the roll off, the decide the volume.
At this point I am pretty confident, I can make it sound quite nice. Not nearly the same as my XJ92 line array but never the less, nice. And with all "life size like" benefits of line array.

Can you get the same midbass bass response out of a dipole array? That's my only concern really. I need to be able to cross these with a sub and nothing else. If so, I might as well just scrap the idea of using a boxed array and run a dipole instead like you. Given the difficulties in modeling this properly, it might very well be my best bet. I'm having enough fun making a TM or TMW out of these.

Would you be able to produce a .frd file that can be used for modeling this dipole line array with my own tweeter? I'm also interested in the fact that a dipole setup will be significantly cheaper to build, as I'll be using an 8 foot plank of pine or oak for this setup. My days of finishing MDF are over.

[r-carpenter]

Re: sony buyout

How low would you want this array to go?
I can produce Frd file as we talked about it but again, tweeters are measured standard 1m which is not far enough for an array. So, you'll need to make corrections to a tweeter SPL.
I'll post a series of FR measurements from .5 meters to say 3meters in 50cm increases, to shed a bit more lite on arrays FR.

[XtremeRevolution]

Re: sony buyout

How low would you want this array to go?
I can produce Frd file as we talked about it but again, tweeters are measured standard 1m which is not far enough for an array. So, you'll need to make corrections to a tweeter SPL.
I'll post a series of FR measurements from .5 meters to say 3meters in 50cm increases, to shed a bit more lite on arrays FR.

I'd like to get into the 80s if at all possible, 90s at least. Past that and I may potentially have problems crossing over to the sub, which will be down firing. Is this possible?

Would this be easier if I just mailed you one of my tweeters? I do happen to have about...8 pairs of them right now. I'm otherwise not sure how I could get this modeled. Of course, I could just play around with padding resistors till I get it right.

What kind of corrections would you suggest? Sorry for all the questions, I'm learning a lot here.

[zobsky]

Re: sony buyout

It shouldn't be an issue getting down below 100 Hz.

In an open backed array (U baffle) I built a while ago with drivers having similar T-S specs, I got response into the 60's and even a whimper at 50 Hz.

IIRC, the dimensions of that design with 9 woofers per channel:

http://img128.imageshack.us/img128/1998/baffleuik8.jpg

1. around 6 ft tall
2. 1 ft wide with U baffle wings at each side, parallel to each other. This was a laziness compromise. Ideally, the wings would not be parallel to each other, rather splayed a few degrees apart
2. the wings starting around 8" at the bottom and tapering down, to I think 4" at the top of the array. Not really necessary to do this but I wanted the option to seal the rear and keep the top open creating a quasi TL in case I wanted to extract the most bass out of the design while controlling boom and flattening the impedance curve

[michiganpat]

Re: sony buyout

Can you get the same midbass bass response out of a dipole array? That's my only concern really. I need to be able to cross these with a sub and nothing else. If so, I might as well just scrap the idea of using a boxed array and run a dipole instead like you. Given the difficulties in modeling this properly, it might very well be my best bet. I'm having enough fun making a TM or TMW out of these.

Would you be able to produce a .frd file that can be used for modeling this dipole line array with my own tweeter? I'm also interested in the fact that a dipole setup will be significantly cheaper to build, as I'll be using an 8 foot plank of pine or oak for this setup. My days of finishing MDF are over.

dumb idea regarding your TM version, but do you have any frequency response measurements off axis?

take a look at the Acoustic Research Holographic imaging series from the early 90's. they have the woofer angled up at a near 30 degree angle, with the tweeter in a baffle below angled back at like 5 degrees. the tweeter was crossed over at 3500 hz with a 2nd order electrical filter, and the woofer was run wide open. the off-axis mounting gave a mechanical high pass basically, and also helped with spaciousness in the sound

might be a cheap, easy way to address that big response spike at 5khz...
for the TMM, not sure how this would work, unless you made it a 2.5 way, with the 2nd woofer low passed at ~500hz...

[XtremeRevolution]

Re: sony buyout

dumb idea regarding your TM version, but do you have any frequency response measurements off axis?

take a look at the Acoustic Research Holographic imaging series from the early 90's. they have the woofer angled up at a near 30 degree angle, with the tweeter in a baffle below angled back at like 5 degrees. the tweeter was crossed over at 3500 hz with a 2nd order electrical filter, and the woofer was run wide open. the off-axis mounting gave a mechanical high pass basically, and also helped with spaciousness in the sound

might be a cheap, easy way to address that big response spike at 5khz...
for the TMM, not sure how this would work, unless you made it a 2.5 way, with the 2nd woofer low passed at ~500hz...

The thing is, I can't predict where these will be placed, and they certainly won't be used in a specific listening room. A lot of these will be gifts, so I can just run the woofer wide open and off axis expecting someone to not place them on a small coffee table in a corner, because the moment they stand up, it all changes.

I also don't have any frequency response measurements off-axis. I'm using only what r-carpenter measured.

[michiganpat]

Re: sony buyout

of course, once you get into room reflections, and listener positioning, even the most ruler flat on axis speaker can have audible bass nulls and 10-20db midrange suckouts depending on listener position....

[r-carpenter]

Re: sony buyout

I'd like to get into the 80s if at all possible, 90s at least. Past that and I may potentially have problems crossing over to the sub, which will be down firing. Is this possible?

Would this be easier if I just mailed you one of my tweeters? I do happen to have about...8 pairs of them right now. I'm otherwise not sure how I could get this modeled. Of course, I could just play around with padding resistors till I get it right.

What kind of corrections would you suggest? Sorry for all the questions, I'm learning a lot here.

Sure, you can send me the tweeter.
I am going to work on this array next weekend, so let me do FR measurements at different distances and then you'll see yourself.
I am guessing, you can get in to a 100hz area with Sony but why? What kind of bass driver or a sub are you using?

BTW, U-pole very good idea. Thanks Zobsky.

dumb idea regarding your TM version, but do you have any frequency response measurements off axis?

off axis response in the semi point source will directly relate to the size of the cone, 5k-6k resonance will not disappear off axis and even with natural array roll off will have to be notched anyways.

My suggestion is not to get involved in to TM, TMM or MTM with this driver. Sensitivity is low, distortions are highish, motor is weakish.

[XtremeRevolution]

Re: sony buyout

Sure, you can send me the tweeter.
I am going to work on this array next weekend, so let me do FR measurements at different distances and then you'll see yourself.
I am guessing, you can get in to a 100hz area with Sony but why? What kind of bass driver or a sub are you using?

BTW, U-pole very good idea. Thanks Zobsky.



off axis response in the semi point source will directly relate to the size of the cone, 5k-6k resonance will not disappear off axis and even with natural array roll off will have to be notched anyways.

My suggestion is not to get involved in to TM, TMM or MTM with this driver. Sensitivity is low, distortions are highish, motor is weakish.

Can you send me your address to ship the tweeter?

I'm currently using two 10" subs sealed. I am planning to bring in a 15" ported sub. I just thought it would be a better idea to cross lower than 100hz.

I guess I'm building two line arrays then. That should use up all of the drivers I have and give me a nice bit of sound. How would placing two of these line arrays sound next to each other? How about two tweeters and 24 drivers per baffle?