Monday, June 1, 2015

Bottleneck Meet - May 2015

We met at Steve's house again. John (2wo) came down with me in my Mini Coachman that was loaded to the gills with my stuff. The time goes much faster when you have somebody to talk to. The photos are blurry but you will get the idea.

A year or so ago, I bought a couple of the high QTS Goldwood 18 inch speakers that I tried in an H frame based on Martin J King's article. I soon had orders to remove them from our living room and so I disassembled them and the plywood sides of the H frame (16" x 21") have been used as top plates for my latest amplifiers.

At our last meet, Roscoe brought along his version of the JE Labs open baffle that uses these same speakers. I was very impressed by the quality and amount of low bass so I built my own version using laminated cherry flooring from Lowes. Instead of using a standard crossover, I used a PLLXO and bi amped with a digital amp for the bass and my Cat Vomit 6C33C amp on top.

I tried a few different speakers on top but eventually preferred the old 99 cent Parts Express speakers that were well received over a decade ago. I also brought along an array of these same speakers, 9 per side, mounted on a piece of polycarbonate (4' x 1').

The 99 cent speakers are the ones that PE sold initially, not the different 99 cent speakers they sold later that did not sound near as good.

To be honest, I was disappointed in how the arrays sounded, no where near as good as what I achieve at home. Room dependence may be one of the problems with open baffle arrays. Still, they didn't sound all that bad and in fact were pretty good.

And of course, I was stunned that both channels of my amp worked. I think the reason is that the plywood top plate flexes less than the polycarbonate I have been using for years. I don't like using metal since I invariably cut myself when I use metal.

We tried to get the Bottlehead DAC to work with my Dell netbook but had problems with the driver. John remembered that the instructions said that something special needed to be done but couldn't remember what since he uses a Linux server. We had listened to the B'head DAC earlier and it sounded very good but we couldn't do the ODAC / B'head DAC comparison as we had hoped. There is always next time. John also has the ODAC and says that the B'head DAC is much superior once it has broken in.

Steve then brought out his foam speakers powered by Dayton exciters. I was prepared to be underwhelmed, but to be honest, combined with the 18" woofers, this produced some of the best sound I have heard in Steve's room.

We were all amazed.

The exciter which is currently out of stock at PE. It now costs $18.50. Note the cryogenically treated ultra pure silver cables.

I thought the panels improved when they were raised up on the chairs. We discussed possible diffent ways of suspending the panels.

We were all so impressed that we are going to hold a competition in October where your entry has to be a pair of panels driven by this exciter. I will bring along the same woofer open baffles so that we all just have to bring along our foam panels.

This is worth playing with. It's not perfect, but these panels produce better than decent sound and should be fun. Steve is going to send me some links to various discussions about these exciters and I will include them in the blog.

Very blurry photo of the electronics. The 6C33C amp is supposed to deliver 14 watts and it easily handled the foam boards.

Tony and Steve each had a pair of old Wharfdale speakers so they stacked them and we played them for a while. Earlier in the day, they had tried some other vintage speakers. All I can say is that the Wharfedales were nowhere near as good as the foam panels / 18" woofer combo. The treble seemed to be missing and there was not much bass.

We then tried a pair of old Radio Shack speakers and they sounded a lot better than the Wharfedales.

The other odd thing about this meet was that since we used my laptop as the music server, we listened mostly to music that I chose. Most of it was music we have listened to before but there was some new stuff, including some by Shirley Rumsey. Her voice is stunning.

We also listened briefly to Tony's Koss Electrostatic headphones. I loved the sound and they were very light and comfortable. Although I am not a headphone fan, I think I could live with these.

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