My DIY Active 3-Way Floorstander!

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This is an Active 3-way floorstander using cylinders to mount the drivers.

I have used the following drivers for the project.

Brand: Peerless Fabrikkerne(I) Ltd.

1" Fabric Dome Tweeter: SR10DT x 1
5.25" Coated Paper Cone Mid-Range: M13NH x 2
10" Paper Cone Woofer: SB25NP x 1
Per channel.
The Cylinders are of HDPE (High-density polyethylene) Pipe.
Cuts are made with Metal Lathe.
Frame made with two pieces of 1/2" MDF sticked together to form 1" thickness.
Mainly intended for Tri-Amping.
Dimension: 4.2ft (H), 1.3ft (W), 10" (D)

Link provided below you can find images of all the major steps for this DIY Floorstander.

https://picasaweb.google.com/104550501856680949171/Active3WayFloorstanderProjIII
 

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Just another Moderator
Joined 2003
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Unusual design! and an interesting way to achieve time alignment. Have you any measurements of the finished product, and listening impressions? The link to the picassa album is not working.

I'm curious how the asymetry of the design affects diffraction.

Tony.
 
Does the sharp edges of each tube cause audible diffraction problems .
I see many designs with drivers sticking out and wonder about diffraction issues. There was an article ( or a thread ?) where the effect of sharp edges on the driver causing ripples in the response was shown. Flush mounted vs protruding mounting.
Interesting arrangement . A bit like Anthony Gallo ?

Beautifully built !
 
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Does the sharp edges of each tube cause audible diffraction problems .
I see many designs with drivers sticking out and wonder about diffraction issues. There was an article ( or a thread ?) where the effect of sharp edges on the driver causing ripples in the response was shown. Flush mounted vs protruding mounting.
You might be thinking of the seminal results of Harry F.Olson. I have quoted the relevant findings. Anyone seriously interested in the effects of enclosure shape and driver mounting on the performance of loudspeaker systems, must read this article.

An AES Paper
Presented
October 27, 1950 Direct Radiator
Loudspeaker Enclosures
HARRY F. OLSON
A comprehensive analysis of the effect of cabinet configuration
on the sound distribution pattern and overall response-frequency
characteristics of loudspeakers.



Cylinder
“The axial response-frequency characteristic of the loudspeaker mechanism of Fig. 1 mounted in the center of one end of the cylinder of (C), Fig. 2 is shown in Fig. 8. The sharp boundary at the intersection of the plane and cylindrical surface introduces a strongly diffracted wave. “

“It is also interesting to note that the variations in response are very great, being of the order of 10 dB. “


Conclusions
“The response-frequency characteristics, which depict the performance of a direct-radiator loudspeaker mechanism in various enclosures of fundamental shapes, show that the outside configuration plays an important part in determining the response as a function of frequency. For example, in some of the enclosures the variation in response produced by diffraction exceeds 10 db. “

“The response of a loudspeaker in an enclosure will be modified by the directivity pattern of the mechanism, because the diffraction effects are influenced by the direction of flow of sound energy
from the diaphragm.”

“The experiments described in this paper show that the deleterious effects of diffraction can be reduced by eliminating all sharp boundaries on the front portion of the enclosure upon which the mechanism is mounted, so that the amplitude of the diffracted waves will be reduced in amplitude and by making the distances from the mechanism to the diffracting edges varied so that there will be a random phase relationship between the primary and diffracted sound “
 
It's actually a cylinder shape in "free space" that causes "diffraction ripples"(Because the baffle edge is equidistant from the driver's center for a full 360 degrees) Rounding the edge of the cylinder won't help much for this, but placing them in a half baffle configuration like you did will alleviate a lot of the "ripple" problem.
Beautiful take on the Gallo design..
 
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The active configuration might be as follow:

1. Jean Hiraga Pure Class-A 8+8W RMS AMP for - Tweeters
2. Jean Hiraga Pure Class-A 8+8W RMS AMP for - Mid-Ranges
3. Goldmound Mimesis 120+120W RMS Class-AB AMP for - Woofers

Active Crossover Config. is below:

Voltage Gain: Unity
Frequency response: Within ±1dB from 10Hz to 20kHz
Filter attenuation slope: 24dB/octave
Total harmonic distortion Typically: .003% at 1V RMS
Signal to noise ratio: -94dB unweighted (22Hz to 22kHz) with respect to 1V RMS
Separation between channels Typically better than -100dB from 10Hz to 20kHz
Input impedance 47kΩ
Output impedance: less than 200Ω

Active X-over part is over. Now concentrating on the the AMP building (cabinet design, power supply, amp assembling etc etc..., hope can complete that within a month.
 
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