Line array test

[mazeroth]

Thought of a way today to see how I liked the overwhelming sound of a line array and to test what size I should make. Took (2) 2x6s that are 8 feet long and mounted 12 of the $0.69 cent Pioneer drivers from Parts Express between them. Ran them 3 in series and then the 4 series in parallel to get a 6 ohm load for the woofers. Hooked up (6) of the closeout Onkyo $0.48 tweeters, 2 in series then the 3 series parallel to achieve a 2.66 ohm load to the tweeters. I did this so the tweeters get more power because the double amount of drivers would overwhelm them. I would have liked to have done the whole line of tweeters but I was running out of time and anxious to hear them. I also placed them dead center to where my ears are standing up. The woofers run from about 8" off the floor to almost 6 feet tall. I'm using a car Infinity Kappa 2-way crossover for now just to test.

The sound is HUGE! Without much power (even though my amp does 400w RMS @4ohms per channel) these speakers SCREAM! Unreal to say the least. What I have in the picture is roughly $12 and that's just insane. The "speaker" is about 8" from the wall and it's leaning on a cheap DCI powered subwoofer. I "think" I heard the hollowness you guys were talking about so a threw another 2x6 behind the speaker and got it as close to the woofers as I could. I doubt this is doing anything because I really can't tell a difference.

As far as this being an open baffle, is it really since there are air holes between each speaker? Will doing this the right way (cutting each hole out so the speaker fits snug) make this sound a lot better? Will placing a full tweeter line help a lot, even if I am listening level height to the middle of the tweeters?

Listening to rock I am overwhelmed by the sound, but the quality can't touch my Polk LSis. When listening to my fiancee's Norah Jones the sound was just awesome. Less stress on the speakers compared to rock made them sound a lot better. If this is a good representation of how they're going to sound when finished I'm not as pumped as I used to be. Another thing is I'm not sure if open baffle will work well because in my townhouse in my listening room (that is my living room) I pretty much have to put the speakers close to the wall because the rooms are kinda small. Might have to go sealed with these.

I was running the DCI sub at the top 160hz crossover point to help with the low end. It helped.

Oh well, not too bad for $12, I guess. Please, any help and encouragement is greatly appreciated. I've never built a speaker in my life and reading through these threads gets pretty confusing for a newb like me.

Show me the light! LoL!

Thanks!

[Fenris]

Check out this thread:

Finished the line array

AJ and I have both recently finished line arrays with these woofers. You're definitely open baffle, but with not an ideal baffle.

[mazeroth]

Fenris, I'm the guy in your thread that asked you to post a few more pictures. I'm still in awe over them. VERY SWEET!

As I stated before I am a HUGE speaker building newb. I installed car stereos at Circuit City for a few years in college and built a bunch of sub boxes etc. I always preferred the sound of a sealed box with the subs and was wondering how these 69 cent wonders would sound in a sealed line array? What do you think? I think, from the specs, they take about 1/10th of a cubic foot each, so to do this I'd probably use a wider front baffle and mount the 4" and the tweeters to it, and build the other 3 sides of the sealed enclosure just behind the 4" woofers. Heck, I could even go ported and get a lower hz, allowing a powered sub to be crossed over sooner, and even sounding better without a sub. Gah, I don't know! I get chest pains thinking of how much work I have ahead of me and all that I need to learn. I'm in no rush to build these and I know it's going to be a heck of a project!

Sealed?

[johninCR]

With baffle gaps that big, you are probably losing alot of the midbass. That xover isn't helping, especially with different impedances. While you have it set up, try without the tweets and let the 4's go full range with the understanding that the top end will be missing. Give the tweets a listen alone too, but with at least a cap to protect them from over excursion, they probably aren't worth much effort.

[mazeroth]

"That xover isn't helping, especially with different impedances."

I thought the varience in impedances just meant the tweeters were getting more power than the woofers, allowing them to play a little louder than they would to help compensate for their lack in numbers? The woofers are 86db @1w while the tweeters are 85db @ 1w.

"Give the tweets a listen alone too, but with at least a cap to protect them from over excursion, they probably aren't worth much effort."

What do you mean by, "they probably aren't worth much effort"? You mean it's not worth my time to cut the excess plastic off and their use in my line array?

Thanks!

[johninCR]

That xover was designed for specific impedances. Connecting different impedances to it will make it function incorrectly.

I've never heard those tweeters. You should listen to them to see if they have strong points that an array can take advantage of. At low levels do they provide good clear detail? Can you clearly distinguish the cymbals and other high end detail? If not, putting a bunch of them in an array won't make them sound any better and you shouldn't waste your time.

Cheap 4" drivers can sound very good with their limitations usually being power handling and max good output, so putting them in an array can eliminate their weaknesses by having them do very little work individually. You need to figure out in what frequency range those 4's sound good to determine your XO point. Looking at their FR graph, it looks like it should be at 6Khz or below due to the peak at 7K.

[mazeroth]

Thanks for the input so far.

Listening to jazz-style music is just awesome, even with this 1 hour setup. I can distinguish between the cymbals and every instrument with ease. I tested this array playing at volumes that made my ears hurt at ~15 feet distance and it was still extremely clean sounding. I have no doubt that 2 of these, with more drivers, are going to sound fantastic. I just can't decide if I should go with 12 or 16 4" drivers due to the SAF and whether to go open baffle or sealed. Plugging this driver into WinISD it has an EBP of 116.7, which means port, but when I see the response graph there is a nasty 2db peak at 54hz, then a -1db at 73, then it goes pretty flat after that. I've always like the sound of a sealed speaker but have never really had the chance to do a sealed vs OB.

The car crossover runs a set of Infinity Kappa components that are 4 ohm nominal. Should I wire the tweeters and woofers up for 4 ohms so the crossover will function the best that it can? I know this setup is doing my final project no justice but I'm just using this to give myself an idea of what woofer height I'd like to go as well as tweeter height and number.

Thanks again everyone! Keep the feedback coming. I can't read enough of this stuff!

[johninCR]

Yes wire them both for 4ohms. Keep in mind that XO point is probably much lower than you'll want. To compare OB to a box just connect your Polk to the left channel and compare. The OB is
going to give you clearer dialogue and more natural vocals.

Regarding the number of drivers, more is better (less work for each). However it will sound bigger and since you have a TV, not a projector, the sound size may dwarf your image.

Everything will sound like you are on the front row, but the sound image size will vary. For example, with my 12 4" driver array Barry White recordings give me the image that his head is 3 or 4 feet in diameter. Of course that is the extreme, but something to consider.

[mazeroth]

I do have a dedicated theater in my basement, but didn't feel like carrying this down AND my ceilings are only 7 feet tall down there. Living in a townhouse for the time being until my fiancee and I move and get a house of our own, which should happen in 6-12 months.

In the basement is an 80" 16:9 screen with an Infocus X1. Seating varies from 13 to 18 feet, depending on what mood I'm in. I don't have rear speakers, just a 2 channel setup because I'm not going to put a lot of work into this theater for it will be gone in 6-12 months.

I should mention this as well. This project is for me to learn how to build speakers, get an understanding for how crossovers work, and get an experience with line arrays. These arrays will be going to my brothers, one set each, and maybe some for my father. My final arrays will consist of higher quality drivers and nice tweeters. I do want to get the best bang for the buck out of these, and would like a decent crossover. Seeing how all the drivers for the pair will be under $50 it's hard to swallow making a crossover that costs that much. Anyhow, time will tell...

Thanks again guys! I love the feedback and get excited every time I see a reply