Finally - some speakers

Yep, my wife is out of town so I was able to finish my speakers to a point. They aren't wired up yet, so a review will have to wait.
Will my wife like them? I don't think so.... they are huge!!

They are based on the Basszilla, but different in a bunch of ways.
I used a different 15" woofer (cheaper- Selenium WPU1505)
Also the new Fostex FE208E E
(coolest looking driver on the planet.)

Since the new 208 doesn't have a whizzer, it doesn't go as high as the old 208. I wanted to use a tweeter anyway, so that's a Fostex FT17H below it.

The panel with the 208 can be tilted to adjust high end roll off- It has a rising response until it gives up. I also made the panel thicker around the edges so it doesn't need to be quite as wide, and beveled it.

Efficiency should be around 95dB

If they sound good, then I will veneer the bass boxes, the heads just sit on top and will probably be painted black

a close-up

Thanks for your encouragement
Of course I prefer the comments of Mr. Yayakoshi rather than
the rest of you predicting my doom(probably correctly though )

Whether or not my speakers are intelligent, I did spend a lot of time thinking about the Basszilla design, and have incorporated things I think will help me get the best sound I can.

The major changes:
-the adjustable tilt mid baffle to adjust the rising high end of the 208, the Basszila is tilted but fixed.
-The tweeter, (Basszilla has no tweeter)to get the high end back , actually it fills in at a much higher frequency around 10k Of course coherence might suffer from this, but I hope the high roll in will save me!
-The open baffle has small sides, which should keep it from having to be as wide and dampen resonannces, with very little boxy effect since they are so small.

At the moment I have just the 208 hooked up to my Hafler 220 power amp and Cambridge Audio D500 CD with runs of CAT 5 cable to the speakers. Not optimal, but good signs!

Tone of instruments? Excellent! Resolution? very good!
Speed? (I know, controversial term ) Very good.

I have to think that if you took the 208 and put it in a 4'x 4' baffle (instead of my 18") and set it on the ground, that in many regards it would be better than 90% of the speakers out there! It is definately in High End territory. They need to be tilted back a bit to de-emphasize the high mids, but NOTHING like a Lowther which I find impossibly irritating without corrections. With the baffle I have, the cone cane barely be seen to move at highest volumes. I think the new 208 has a lot more travel and could be used with a much bigger baffle than I have without running out of travel. The 208 is run full range, the 15" will be rolled off around 190- 200 hz. I probably will try a bigger baffle and bass speaker rolloff at about 150hz someday. That would really get the crossover zone out of the way!

Biggest down side: a pretty consistant hum, even with the volume all the way down. I then turned off the amp and the hum remained! I figured out that my notoriously humming computer speakers were turned on BEHIND the new speakers- Turned those off and no worries!! That was the easiest fix ever!!
Next report- Tweeter and woofers connected!

Mark

Latest update:
I have them wired up, I'm just like all the other DIY guys. I think my speakers sound wonderful!!! I've never had such great speakers in my house! An audio buddy has come over and confirms that we're talking High End quality!
I had to add an L-pad controlling both the 208 and the tweeter, because the 15" isn't efficient enough to match it. But no noticible reduction in sound quality. The tweeter is very important - the 208 doesn't have super high frequencies, and the tweeter fixes that with no problems that I can hear. It is more efficient than the 208 so I guess it should be padded down a bit more than the 208, but it is crossed over so high that it really doesn't seem to matter. The cheaper 15" Selenium drivers sound great- on jazz you can perfectly hear the walking bass, each note distinct and tuneful. The 208 quality is so good that it certainly would be reasonable to spend the money on the Audaxes recommended for Basszilla. On easy stuff like acoustic guitar, it sounds like the guitar is just right in the room with you. On hard stuff like piano, the quick response really gets the percussive sound correctly.I made the open baffle narrower, but with small side walls. Today I tried making the baffle wider with taped on "wings" to lower it's bass, but the sound changed for the worse. I have been very lucky that my changes to Basszilla haven't hurt, but probably helped. I am losing interest in tweaking it anymore, I'm in the "pull out your music collection and listen for hours" stage
Eventually, I will use the Hafler for the bass only, and I hope an X-SOZ for the 208 and tweet. Then I will be able to get rid of the L-pad.
This is one serious speaker- - I don't need better , I'm moving on to making an amp

First, thank you for your kind words. I remember the photos of your backloaded horns with the old 208 and they were beautiful.

You know, I was listening to my speakers today and the bass is really fine, amazing really. I suspect what everyone says about full range speakers AND pro drivers is true-they need time to break in. The bass driver only goes up to about 200 hz, so maybe a lot of the the attributes of higher end bass drivers (smooth extended range for instance) aren't needed. I put on a Telarc Organ CD last night and those low register notes were very distinct and really made the music come alive.

I think I have heard that P Audio stuff is pretty reasonably priced there. It is getting quite a good reputation here, even though isn't very cheap-probably due to shipping those heavy magnets around the world. I paid $100 USD each for my Seleniums, which are made in Brazil, on a very good sale.They aren't particularly well known here or considered that special. The point is that they are good quality high efficiency pro drivers. They are also easily available in the US at Parts Express

If you could get good P Audio drivers for less than half the Audax price I'll bet you would be really happy. If they don't work out, you can make some PA systems for your parties or sell them to a local rock and roll band. 97 dB efficiency would be better than 95dB. The only tricky part would be the crossover.

If you are going to use a tweeter, I think the new 208 is probably the way to go. I'm not sure if I emphasized this, but I didn't use the notch filter he recommends which is a max 3 db cut and super wide, not a surgical notch.Since I am adding the tweeter, I can roll off the entire top end of the new 208 a bit by tilting maybe a little more. It naturally gives up around 10k
Dick had to use the notch because he wanted the response to rise at the top again cause he had no tweeter. I think you could get a good price for your assembled speakers, so the best idea might be to sell them if you are going the Basszilla way. If you can't sell them, then make a Basszilla with the old 208- You can then follow his plans exactly.

I needed to cut the 208 & tweeter with an l-pad because the bass isn't as efficient. In theory, the Audax is 100 db efficient
be to me the curve looks a lot lower in the lower ranges. Dick doesn't seem to have any problem with there efficiencies matching, so: either the Audax is more efficient than the Selenium or he likes less bass than I do. IMHO my bass isn't exaggerated. The reason I used the Selenium was cost only. It isn't going to be cheaper down there!
Of course Eminence is a possibility, The Delta models response looks good, but most of their other drivers have pretty rough response. The Deltalites have good curves with Neo magnets that are lighter to ship too.

IF you didn't need to cut the 208 much, the efficiency will be fine. My plan is to use a big amp on the bass and a tiny amp for the 208 & 17
Maybe you could do the same if your existing amp doesn't do the job. Remember, the speaker is designed for low output amps.

Plenty of punch, the whole speaker is not really warm and fuzzy, but sounds like the instruments are right there and up close It is ported with a 4" hole in the back near the floor. I'm planning to try sealed (would be .6 damping with this cabinet) but am having too much fun listening. I think tubes would work really well

My box is flat to 40 hz according to calcs, when bass reflex. With sealed box it rolls off sooner, but smoothly.
They say the the room will increase the bass. A lot of people seem to prefer sealed big boxes. We'll see.

Here's the link to the Basszilla:
http://store.hifiauthority.com/olsherkits.html

The plans are dsigned and sold by Dick Olsher, an authority in hi fi circles with excellent credentials. Although I changed a lot of things, I know that without his plans I would never have gotten to this point, so I request anyone wanting t o make a speaker based on this design to send him the $20 for info. It is a very good tutorial on the issues of this kind of speaker and well worth the money.

Of course you get the most value from his plans by following his instructions exactly and using his choices of drivers.

THIS IS a huge advantage, because he recently contacted me (wow!) after I sent him photos of my speaks, and requested I make him a copy of my top baffle unit. He said he is planning to design a new model based the new 208, and the FT17 tweet.

I assume that he will stick with the pricey Audax woofer.
SO.... If you get the Audax woofers, the New 208 Fostex and the Fostex FT17 tweeter, you probably have the supplies for the future Olsher authorized model, approved by his ears AND tested with his computer measuring device. He did warn that it might be quite a while before he has time for this though......

Mark Cronander

First to Sandy H : Thank you for the kind comments.
The integration of the tilting baffle head unit is original, but based on information I’ve acquired – mostly on the web! The basszilla uses a tilted baffle along with a notch filter to clean up the response of the older Fostex 208 . Because I was using the new 208, I didn’t know what tilt would work for me so I needed it to be adjustable, Yet I couldn’t tilt the tweeter, because it has a very flat response out to about 30k! After lots of tossing and turning instead of sleeping I came up with this approach. A famous speaker model by Davis in France (this open baffle/ bass box is not as unusual as you might think) has a 15” woofer box, an open baffle with a midrange, and the tweeter between the two. From other sources, I’ve heard that in fact having the tweeter in between is preferable. Another way to do it would have been to mount the tweeter in the uppermost part of the bass box, but
I had just returned from an audio show and seen the new 45k TAD home speakers that had the mid/tweet head isolated from the bass part of the speaker with some kind of elastomer. I had always felt that the bass vibrating the tweeter couldn’t be a good thing, so my conscience made me go with the separate tweet/mid head.

And to all out there:
My wife decided that this was a test for good wifeness, and said that if these were super important to me, then it was OK and we could keep ‘em. I had just replastered and repainted our bedroom before she returned, so I had scored a lot of points. (I’m no fool!)

I have just measured the baffle width and discovered that it is a couple of inches too narrow, so I will add those little wings back and check if the really are a problem or not. The speaker response keeps changing, so I can’t make a definitive call. If I get a few minutes, I will try a warble tone test CD, but just don’t want to lose the little time I have for music listening.

Mark Spa317:

First, you aren’t going to get the Seleniums for 100 USD ea. They were on a good sale here, and are made in Brazil, which is a lot closer to me than you. In Europe they are at least $200 each. They each weigh 25 pounds which is significant when shopping so far.
They are also probably not that special as I mentioned before.
In the same way, one reason Beyma drivers might be considered such a deal in Europe is that they are made close by in Spain. Using this principle, I figured that the P. Audio drivers might be a better deal for you. Yes they are a brand of drivers and they are made in Thailand, and are getting apretty good buzz here in the US.

Here is the URL of t he European distributor: http://www.paudio-europe.com/index.htm

The Australian distributor: www.cannonsound.com.au It worked earlier today but not now…..Their e-mail is admin@cannonsound.com.au
Tel: +61 2 9939 3300 It looks like they don’t really have resellers yet so maybe you can get a good deal.

USA distributor: http://www.paudioamerica.com/paudio default.html
reseller: http://www.speakercity.com/paudio/index.shtml

OK, I had to take a break

To answer some more questions:
-15" pro drivers are pretty interchangable. Track down your driver parameters and use BassBox pro (free) to check out the response, but at most, an adjustment of the port length would be required-probably no change needed.

The FE208E Sigma I used DOES have a worse looking response curve. BUT if you look at the curve for response 30 degrees off axis, the Sigma curve looks a whole lot better. With my setup, the effective tilt of the baffle is around 20 degrees.

I also went for the "newer is better" approach, and I don't trust whizzer cones for my own probably irrational reasons, and the new 208's seem to be designed to an inch of their lives. This must result in some improvement I thought.

The tweeter probably works better on the new Sigma unit, but it was used on the older one too, but crossed a lot higher, say with a 1 mF cap instead of the 1.5 I used.

Check out the Fostex data sheets for the 208's as well as the tweeter models (not just the FT17). They suggest crossovers on the tweeter pages for various 8" models, so you can get a good idea what a good cap value is.

I'll bet the the two 208 models sound more similar than different.

Finally: The Basszilla is a product. It has the name of a reputable hi fi designer attached to it. To get the optimum value from this you need to make an identical speaker. If you change things as I did, you lose the "endorsement" value. In your case this is a possible way to look at it: You have the exact model driver he uses in your possession. Why not make the speaker as he suggests using your driver from the horn. Then if you like the approach, buy the 208 Sigma also. Then try them both in the Basszilla, with and without the notch filter, with more or lesser tilt. Possibly Dick Olsher will have some recommendations for the 208 Sigma by the time you get to this point. When you decide which you prefer, put the other in your Jerico horns and sell them! The bass response of the two is very similar. so the Sigma should work fine in the horns. Then you get back the value of the horn boxes too

As to the Audax drivers: First - they give you a real Basszilla which matches Dicks tuned ear and computer analysis.
Second they have a superb reputation. Third, and very important: they have a very smooth response at the point that they will cross over to the 208. This makes the crossover point less likely to be heard. As I think I mentioned, Dick mentioned to me that he couldn't get the Eminence drivers he tried to cross over cleanly enough for him, which is why he went for the Audax's.

By using your existing 208's maybe you save enough in the short term to get the Audax's. At the same time, I'm happy for the moment with my cheaper bass drivers, so if you find a pair of decent ones for less than half the Audax price, it might be worth it. Check the response curves of your candidates at the crossover point Dick uses. I haven't seen the P audio curves, maybe the Aus distributor has this info.

I'm pretty sure that you will like the Basszilla approach from what you have said. It sure blew me away, and I think a tube amp would make them better.

The P Audio Europe site has all the specs and curves for all
models! Some look very smooth in the 100-300 hz range-nice
You don't need a lot of x-max unless you are planning to boost the bass with an active crossover. The BM (Blue monster) series looks OK but I don't know much. The S series is high end and probably pricey.

No prices though...please report if they are in fact a good deal for you fdown there.

In response to more questions I have received here is more explanation:

I wish to emphasize that I am no speaker expert, but have looked into issues that affected my speakers for awhile before starting.

So, about the baffle size. The published required baffle sizes are usually a square baffle suspended.
You can trade off a short baffle side for a longer one- It's some kind of average of the distance to the edge of the
baffle from the driver that counts.
So.....below the driver I have a huge baffle distance because the entire bass box counts as part of the baffle. In fact if the box is on the floor, then that side is infinately large. On the other sides the baffle has short walls which make it seem bigger to the sound waves. I could have made them longer but didn't want to get a boxy sound.

An irritating feature of sound waves is that they double in size each octave lower.
Let's say for arguments sake that my baffle needs to be 18" square to reproduce 200hz sound without roll off. If I decide to reproduce 100 Hz then I would need a 36" square baffle. 50 hz I might need a baffle 6 ft square!! This is also the reason a tenor sax is a lot bigger that an alto even thought it doesn't really make that many lower notes

This is one of the great advantages of going for a separate woofer.

Check out this program Win ISD PRo at :
www.linearteam.org

It is a free program and in addition to helping you design your bass box, will also tell you the excursion of a driver
at a particular frequency This will help you see how low your Midrange driver will go without exceeding x-max.
(if you have parameters for your drivers)

I'm no jazz expert, but I will look at my meager collection and mention the ones I have that have a particularly clear bass line. The main point of my mentioning this is that on about any jazz track, you can here the bass line distinctly. This is certainly not the case with many speaks!!

OK now to all out there some concerns/ questions:

How much volume up to about 200 hz am I losing due to having the 15" driver mounted high? It occured to me that perhaps this is why the bass is a lot lower level than the Fostex 208. I kept the port within 4" of the floor so I thought this would keep the low notes boosted, but it now occurs to me that maybe the the floor boost goes higher than I thought:


SO: whats the curve of floor bass boost usually look like?
ALSO: Are the +/- 4mm cracks where I have my hinges affecting the response in any way? ie, does bass "leak" through these little openings? I assume that because the are tiny compared to the wavelengths that they don't, but there could be some pressure equalization through them....

SUPER ALSO: I am considering mounting the 208 and the tweet in a tall baffle so that it is easier to pull it out 4 feet from the wall.
So the woofer would be about 2' behind the Mid /tweet baffle.
Considering the the woofer only covers below about 200 hz what would the consequenses be?