TLAHs with JVC 3x5s and 1016 piezos

[AndreasMergner]

These were really easy to build. I did a left and right in maybe 6 hours. Ok, so I used a CNC router to cut the baffles. I did that because I'm going to try some shorter ones with 4 woofers/tweeters for surrounds. It would have taken less time to just use a jigsaw!

I went with 8 of the JVCs, but then used 6 of the "pro" tweeter - they were cheaper ($2 vs 5-6) and more sensitive. They do need EQing, but I planned on doing that anyway.

I built the rectangular version and at 51" long to fit all of the JVCs. I have them standing up in my current room, but they will be hung on the wall at the ceiling in my future dedicated HT.

Cost was <$25 each including wood.

They sound great! ...and louder than I can stand (at least in my current 10x12 room) at nowhere near their max. 4V, which is 4 watts is really loud and 12V (36 watts) is painful.

I'm starting to build my THT now.

[Drey Chennells]

hey nice work Andreas, Ive thought about how this combo would sound myself. Could you describe the qualities a little more? Extension,detail,off-axis response..What, if any, speakers did these replace?

[Tom Smit]

Now, what was it that the others say?....oh yeah, where's the pics?

[AndreasMergner]

One mistake I made was that I probably put too much spacing between the woofers. I know it's a bigger deal with the high frequencies so I just went with it. I didn't want to post pics for that reason....but since you asked.

Pics and CNC video are on this thread:
http://www.avsforum.com/avs-vb/showthread.php?t=1252714

hey nice work Andreas, Ive thought about how this combo would sound myself. Could you describe the qualities a little more? Extension,detail,off-axis response..What, if any, speakers did these replace?

These speakers replaced computer speakers (Logitech 560). Mind you, these are "THX certified". They are actually really good for what they are.

The TLAHs are much better with the highs, which is obvious since they actually *have* tweeters. I am not an expert, but the sound and volume don't change as I walk around my small room. They seem detailed and vocals/dialog is clearer with these vs what I had. I just tested some sine waves and it seems to have decent output to 60 hz, but 80 is a bit stronger.

[chrapladm]

What did your TLAH's end up weighing?

[el_ingeniero]

And why have the long axis of the speakers vertical?

I would have oriented them horizontally, less space between the center to minimizes combing.

[Bill Fitzmaurice]

I would have oriented them horizontally, less space between the center to minimizes combing.

Vertically they have wider midrange dispersion, and there's no such thing as combing with vertical sources.

[el_ingeniero]

I would have oriented them horizontally, less space between the center to minimizes combing.

Vertically they have wider midrange dispersion, and there's no such thing as combing with vertical sources.

OK, I must not be understanding something. I thought there was some constraint dealing with the relationship the center to center distance between the drivers and the wavelength. I'll go back and reread my sources on line arrays, and see if I can get enlightenment.

[gilscales]

I would have oriented them horizontally, less space between the center to minimizes combing.

Vertically they have wider midrange dispersion, and there's no such thing as combing with vertical sources.

OK, I must not be understanding something. I thought there was some constraint dealing with the relationship the center to center distance between the drivers and the wavelength. I'll go back and reread my sources on line arrays, and see if I can get enlightenment.

I am confused on this one as well

[Sydney]

I thought there was some constraint dealing with the relationship the center to center distance between the drivers and the wavelength.

There is...
Multiple sources of sound emission cannot share the same physical space. The spatial offset difference means that there will be frequencies whose wavelengths are close to the offset spacing. Phase shift results
Summation of harmonic forces works in the same fashion in all domains.
A 1/2 wave relationship is a cancellation.
The pattern can be seen by looking a graph of comp filtering.
Since it's a phase wheel - the pattern repeat at multiples of the 1st cancellation frequency.
Bob McCarthy breaks down the summation into regions. Starting with full summation at near zero phase spatial offset, into the other zones as phase shift increases. ( See his work, especially Summation math )
In a line array with multiple sound sources: each element has a varied spatial ( and thus phase ) relationship with the other elements.
The aggregate dispersion pattern that results is determined by summing all the output of the elements ( see Mark Ureda and his sources )
Syd

[Bill Fitzmaurice]

I thought there was some constraint dealing with the relationship the center to center distance between the drivers and the wavelength. I'll go back and reread my sources on line arrays, and see if I can get enlightenment.

Beware sources that are so bound up in formulas that they fail to consider what matters: how it sounds. Center to center distances are critical when drivers are placed on the horizontal plane. When drivers are placed on the vertical plane, not so much.

[Sydney]

how it sounds...

That is a function of the human perception, because human ears are oriented and optimized in a horizontal plane.
Sound interaction is not bound to a particular axis.

Syd

[Bill Fitzmaurice]

Sound interaction is not bound to a particular axis.

Syd

When horizontally placed sources are too far apart you get combing on the horizontal plane, which causes the sound to change as you move across the sound field. The same will happen on the vertical plane with too widely spaced vertical sources, but the nature of listening areas and audience seating being what they are that tends to be at most a minor concern, so long as the driver spacing isn't extreme. Extensive testing of vertical arrays by JBL (for one) has shown that center to center driver spacing isn't nearly as important as the distance between the radiating planes of the individual drivers, and when that distance is held to 10-15% of the radiating plane dimension integration of the individual wave fronts is quite adequate at normal listening distances.

[Sydney]

The same will happen on the vertical plane with too widely spaced vertical sources,

Precisely

[Turntablist]

I would have oriented them horizontally, less space between the center to minimizes combing.

Vertically they have wider midrange dispersion, and there's no such thing as combing with vertical sources.

OK, I must not be understanding something. I thought there was some constraint dealing with the relationship the center to center distance between the drivers and the wavelength. I'll go back and reread my sources on line arrays, and see if I can get enlightenment.

Apart for the explanations done by Sydney and Bill you can google "ARF" or "Active Radiating Factor". You'll learn what effects irregularily shaped drivers have to the center-center spacing rule.