New project underway: Fostex and Pyle Pro

[Fast1one]

One thing I forgot to mention is that the Pyles have motor/mechanical noise, pretty average or slightly louder than average with my experience. Not to big of a deal, not audible to my ears when playing music at the listening position.

I lowered the crossover point on the FF85s today. Went all the way down to 200hz and they weren't to strained at all only moving a fraction of a mm while playing Radiohead (did very well with complicated tracks), the Doors, or the Beatles. Still didn't want to take a chance, nor did I want to strain them more than they needed to be. Currently they are crossed over at 300hz and they barely move at all with pretty much everything I throw at them. Obviously wasn't playing them at live levels, but they were plenty loud, probably around 100db average in my 12 x 15 foot room.

So on that note, I think a 12db/octave crossover at 300hz is just fine and dandy for most applications playing music open baffle. Unless of course you are trying to fill a massive living room. In that case the 400hz would be better suited, better yet a bigger driver.


Also, I have found a new problem moving so much air in a tiny room. EVERYTHING buzzes, from picture frames to the doors themselves

Cheers!

[seanzozo]

Your XO at 300hz and 140hz sims well. The only--minor--problem about running the FF85 that low is that the dipole hump centered at about 600hz of ~2db is not reduced as much by the lowered crossover.

Sean

[Fast1one]

Originally posted by seanzozo
Your XO at 300hz and 140hz sims well. The only--minor--problem about running the FF85 that low is that the dipole hump centered at about 600hz of ~2db is not reduced as much by the lowered crossover.

Sean

Yeah I haven't really noticed anything sticking out like a sore thumb. Everything is very smooth and balanced.

Playing some Jazz now. Glorious! I guess I COULD add some equalization and more power for the low end. But I ask myself, why? I think it sounds beautiful as is. I will probably do some light modifications to the woofers, but they will be purely mechanical. I have been looking into removing the dust cap and some basket modifications.

I am very happy with the results. Can't thank Dave enough for the baby Fostexs. Every time I play something new I am impressed all over again. I would also like to thank Martin King for his fabulous OB articles. They were a lot of help.

Last but certainly not least, you, seanzozo! Great help from beginning to end, can not thank you enough!

[lazenna]

Don't forget to take pic's of the mods so we can all have a look, and let us know how they sound.

[Fast1one]

UPDATE

First off, I upgraded to two Dayton plate amps, which do 170 watts at 8 ohms and 240w at 4 ohms. I spent a couple hours doing some minor modifications to the bass drivers. I did two things:

1.) I added some Cascade Audio engineering VBMAX sound deadening to the frames. A car audio vibration dampener Being stamped steal, they had a significant amount of ringing to them. I added some to all the spokes and added some around the perimeter where the magnet joins the frame. Just knocking it with my fist I could I already tell it was going to make a big difference; Very solid and no ringing whatsoever. I started playing music and WOW. What a difference, the upper response (150hz+) of the drivers was cleaned up quite a bit to my ears. Was surprised at how significant it was. DEFINITELY recommend it! This should be the very first thing you should do before you even play them. But this was only part of the equation. I turned off the music and did the following.

2.) I added 10 ohms (two 20 ohm 20 watt resisters in parallel) in series with each driver. To raise QES, and therefore QTS.

All I can say is, WOW. HUGE difference. Before since there as a rising response, it really brought out the worse of the Pyles, particularly when crossed over high as previously mentioned. Now that the bass is more full and extended (easily to ~40hz to my ear), the pyles sound MUCH better and are now crossed over higher at about 160-170hz with no issues. Interestingly enough, I found my self pushing them a lot less, mechanically, since the presence of the low end allowed me to turn the gain down. Not to mention the amplifiers are now running a at 8 ohms, so they run cooler.

WONDERFUL macro and micro dynamics , dear God this is music. Eric Clapton Unplugged in particular was breath taking. The speakers are complete. Or should I say, what speakers? They completely disappear into the room!

Cheers!!! Long live music!

[BudP]

When you next decide to "do" something, EnABL the woofers too. You have the basic patterns needed on the Fostex drivers. They just need to be scaled up and applied. Check Dave's site to obtain a kit for materials from Ed LaFontaine... $30 for enough to do your four woofers and all of the rest of the speakers in your dorm.

The difference will be that the Pyle's will disappear, with the Bass knit into the Fostex drivers and, you will easily be able to cross them over at 300 Hz or higher, without steering effects coming into play. They will have a dispersion width controlled by the angle of the cones and higher frequencies will not close that down. Plus, all trace of harshness will disappear. Plus, you CAN do it your self.

[human.bin]

how loud does the little fostex go crossed under 200hz? don't you bottom their 1mm xmax?

[Godzilla]

This looks like a really great project to me. Experimenting with the resistors and switching to a more powerful amp appears to have made a very positive difference in the bass. I can only imagine how rich and full those woofers must sound in your relatively small room. Not surprised everything buzzes. LOL. The fr charts were great to see. Wonder if the dip in response around 1.5khz improves sound quality by reducing sibilance... or if it reveals itself at all in real world listening?

Even tho it took a lot of research and fine tuning ultimately you've built something that probably sounds quite incredible for not so much money. One day you may find a friend willing to let you borrow his expensive B&Ws (or other expensive hi end speakers) for a listen. Don't be surprised if they sound like their woofers are broken... or their tweeters are blown. Enjoy!

Godzilla