[FredT300B]

These are called the FrugalArrays because they cost only a bit more than $100/pr to build. Each speaker includes twelve Parts Express 5.12" Sony buyout woofers with a single Vifa DX25 tweeter. The woofers run full range; the tweeter uses a 3rd order crossover. The 3/4" mdf baffles are 6' tall by 16" wide.

So how do they sound? Much better than what 95% of the people I know listen to. My musician friends will think they are wonderful. My audiophile friends will acknowledge they sound very good for what they are. Both groups will be correct based on their reference for good sound.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-012

http://fredt300b.smugmug.com/Hobbies/Speakers/132721_kcDVmw#1512196823_37hRx64

[Russell Dawkins]

I like this sort of design - huge bang for buck, and I love certain characteristics of line arrays. I think they make outstanding PA speakers.

[FredT300B]

I've posted some FrugalArray in room frequency response measurements on the AudioRoundTable forum. The four in-room frequency response measurements are 1) A single point source Sony buyout driver installed in the 16" wide baffle and measured at one meter, 2) The 12 driver array at one meter, 3) The array at three meters, which is the actual distance from the listening position in my room, and 4) The full FrugalArray including the tweeter, measured at three meters.

It's interesting to see how an array of drivers measures differently from a single point source driver, and also how an array measures differently as you increase the distance to the listening position. In this design comb filtering begins to effect the measured response at a surprisingly low frequency. Scroll down this thread for the measurements:

http://audioroundtable.com/forum/index.php?t=msg&th=16614&start=0&

[FredT300B]

I like this sort of design - huge bang for buck, and I love certain characteristics of line arrays. I think they make outstanding PA speakers.

Russell, Bose has reached the same conclusion about line arrays as PA speakers, and their L1 has been very successful for live performances in small venues. http://www.sweetwater.com/store/detail/L1m1B1/

In the high end audio arena some of the most impressive speakers I've heard have been line arrays. The comb filter effect can produce some unwanted consequences, and a serious like array (unlike my fun project) requires some creative crossover tweaking to get the sound right without overloading the room with bass. http://fredt300b.smugmug.com/Hobbies/Speakers/132721_kcDVmw#27073926_S4zvX

[Ric Schultz]

Fred,
Does the 5K peak smooth out when used together in a line array?  I see you measured them.....do you have a graph?  I bet they sound good.  You should felt around all the drivers and seriously brace the baffle (of course making the baffle three thicknesses thick with Green Glue would be over the top).  Then the sound will be mucho better.

[SteveRB]

that project looks like a lot of fun -- can you share a wiring diagram?

[FredT300B]

... can you share a wiring diagram?

The woofer array is wired for six ohms nominal impedance, with four groups of three drivers per group wired in series.

[SteveRB]

now i'm curious:

what happens to the character of the array if you low pass crossover one of the groups of three? any gain in bass response?

[Ric Schultz]

oops, I see that you posted the frequency response.  Very nice!

[Æ]

now i'm curious:

what happens to the character of the array if you low pass crossover one of the groups of three? any gain in bass response?

Not my thread, not my build, but my 2 cents. No matter how hard you try, no matter how much baffle step correction or equalization you apply, you're never going to get any real bass from those small Sony drivers. They were never designed for bass. Look at the specs, fs is 81Hz. They just aren't capable of it. Years ago PartsExpress had their similar 69 cent wonders on sale. I listened to a very large ported array using them. Plenty of dynamics, but NO BASS.
http://ratch-h.com/farm.html

[FredT300B]

...you're never going to get any real bass from those small Sony drivers. They were never designed for bass.

You are correct. Using 1khz as a reference point they are down 3dB at about 60hz. About the same bass response as many mini-monitors using a 5.25" midwoofer. But this begs the question of whether deep powerful bass response is a "must have" or a "would like to have", especially in a speaker that cost less than $150.

For me there are two absolute requirements for any speaker, and no matter how well it does anything else, if it can't do these two things I don't want it in my listening room. Those two things are 1) It must have reasonably accurate frequency response from about 100hz and up with no large peaks and nulls, and 2) It must be able to play at room-filling levels with no audible distortion. The FrugalArrays do ok with these two tests.

There are also several characteristics I would "like" to hear in a speaker, and the first is deep powerful bass. The Frugalarrays fail this test, but they don't sound anemic. In most of the music I listen to there is enough fundamental and harmonic frequency information above 60hz to provide some illusion of bass. For many people, deep powerful bass into the low 40's is a "need" rather than a "want", and these people would not like the FrugalArrays without a subwoofer.

[FredT300B]

now i'm curious:

what happens to the character of the array if you low pass crossover one of the groups of three? any gain in bass response?

Ratch is right. These 69 cent miracles have some limitations, and I suspect anything you do to get deeper or more powerful bass will have an unacceptable negative effect on some other area of their performance. The solution to the need for more bass is to add a subwoofer.