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Giovanni Militano    Canada Flag     To email Gio, type out the email address.

Page 1: Introduction, Background, Driver, Design
Page 2: Construction, Sound


There is little I can add about the enclosure construction as it was completed by a friend (Andrea with help from her dad) at what I like to call the Minnedosa speaker factory. I can't thank them enough because if it was up to my carpentry skills, the drivers would still be in their cardboard boxes. The enclosure was constructed from birch plywood and put together using an air nailer and glue.

BD-Pipes Enclosure - Baltic Birch Plywood
Photograph 01: BD-Pipes Birch Plywood Enclosure

To give the drivers some room to breath, I made a chamfer behind the driver using a coarse wood file. A router would have been cleaner, but you can make a lot more room behind the driver with a file.

Chamfer Behind Driver
Photograph 02: Chamfer Behind Driver

I had a few problems trying to find suitable damping material. I ended up buying furniture upholster felt and it seems to have worked quite well. Each driver is connected to a separate pair of binding posts. This provides me with a lot of flexibility. Using one amp, I can easily connect the drivers in series for a 16 ohm load or in parallel for a 4 ohm load. The separate pair of binding posts also allows me to easily bi-amp the speakers using one amp for the front driver and a separate amp for the rear facing driver. The dual binding post speaker plate was purchased from Radio Shack.

Damping Material - Upholsters Felt
Photograph 03: Damping Material - Upholsters Felt

Currently, the speakers do not have a finish. I think they look pretty good with no finish, but the plan is to put some sort of finish on them.

Unfinished BD-Pipes DIY Loudspeaker
Photograph 04: Unfinished BD-Pipe Speakers

Total costs for this project was about $140CDN as I got the Radio Shack drivers at a very good price. If you are planning to build this project with new Fostex drivers, expect to spend about double that amount.


To the most important part! How do they sound? In one word ... Great! Starting with the obvious, being full-range and thus providing point source sound combined with no crossover to mess with the phase you get great imaging, a wide soundstage and good depth. Most surprising about this speaker is the bass response, which is much better than I was expecting considering that the drivers are only 4". The midrange is the strength of these speakers and the treble is fairly extended. While the treble is extended, a Radio Shack 40-1310 Super Tweeter provides some air and sparkle at the top end. With their big magnets, the drivers are fast and the single drivers provide that coherency which multi-driver speakers often lack. My only criticism is that the upper end is a little forward and can get muddy at moderate SPL. Hard rock music does not sound very good on these speakers.

In playing around with different amplifiers, I found that the midrange of the BD-Pipes improves significantly when they are driven by an amp that does not have extended bass response. I experimented a little more and found that using a tube amp which has limited output below about 100 Hz and mating the BD-Pipes with a subwoofer, the midrange improved significantly and the sub helped fill in the bottom end. I suspect that putting bass through these drivers affects cone control and the midrange suffers.

Overall, I am still very pleased with the performance of the speakers. I use these speakers as part of a bi-amped two channel system through a NAD 1020 preamplifier. The BD-Pipes are driven with my S-5 Electronics Tube Amplifier and the Radio Shack 40-1310 Super Tweeters are driven using a small SE 50EH5 Tube Amplifier.

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Introduction, Background, Driver, Design
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