Dipole or Monopole?

[Dennis H]

Hank, remember the foam or wool is only half the story. The other half is EQ and I haven't gone there yet. From my limited tests, the more foam you use, the better the off axis response matches the on axis but it also rolls off the highs more. So there would be some happy medium where the off axis was pretty good and not too much EQ was required. Deciding how much EQ is "too much" would be where a lot of testing comes in. Also keep in mind that the Monsoon panel is pretty thin like a BG Neo8. The RD's have a metal horn in front and that might (or might not) make it trickier to mount the foam or wool so it would do what you wanted.

[PMazz]

Anyone know anything about Radia Pro Systems? They look like they have a varient of the B&G stuff. They are 5 minutes from my shop so I thought I'd contact them.

http://www.radiapro.com/speakers.htm

Pete

[ThomasW]

Pete

B&G recommends a min 15' for the RD-75's I certainly agree with that. They recommend 10' min for the RD-50's, 8' min for RD-40's. I've never played with any RD-50's but I trust their recommendations based on my experiences with the RD-75's

They (B&G) state "Smaller (this means shorter) listening distances may result in a somewhat subjective perception of decreased output at the highest frequencues. This limitation can be overcome in smaller systems with a compensating supertweeter." This info is from the B&G whitepaper available from PE.

In the family room the RD-75 are physically HUGE. Given that I listen anywhere from 6'-16' I'll probably go with the Arvo design.

I believe that the ProRadia panels are expensive and no discounts are available unless someone is friends with a dealer. They have 6 elements instead of the 4 in a retail RD-75/50/40. I believe they use a higher temp plastic membrane for the planar element = higher power handling. They are tough enough to be used for PA applications.

BTW B&G has a toll free number and Robin Ellis is a very nice fellow to talk with.

Hank

Since the temps have finally dropped out of the 90+ degree mark I'm trying to catch up on a ton of homeowner chores abandoned last June. So extensive audio experimentation will be postponed until Jon gets here the last week of Sept or the weather heats up again.




theAudioWorx
Klone-Audio

[PMazz]

Well, thinking about the RD 50 again leads to the same damn problems. The FF/NF transition is up too high to use a simple "bass box". We'd be back to a 6' high line with 6.5s or 8s, and they should really be Xed over at ~1KHz to maintain appropriate levels at the listening position. AARGHH!

I may just get a pair of RD50s to see just how bad this would be. Maybe I'm just putting too much stock in the formulas. Time to do some listening, methinks. Besides, I'm sure Hank would be interested in a deal if they don't work out. Work has gotten back to normal, so time is now the problem again.

Pete

[ThomasW]

Pete

I perhaps should clarity my RD-75 statements. They sound quite good at a 10-11' listening distance, if the output levels are adjusted for that distance. But the real 'magic of a true holigraphic soundstage occurs when the listener is at distance of 15'+'




theAudioWorx
Klone-Audio

[Hank]

Holographic magic is what I'm pursuing. I can't think of any questions right now. If I do this magic box, it seems RD50 alongside a stack of 6"'s in a trapezoid enclosure. Oh yes, one calrifying question: If I enclose the 6"ers (maybe ported in back), what's best for the ribbon, monopole or dipole, or put another way, if the RD's done dipole are best for "magic" sound, does that dictate the woofs be on a dipole panel, or can I enclose them?
Damn I love being a newbie! ops:

Okay, I'll back off for the rest of September so Thomas can work on his home maintenance list.

[JonMarsh]

You know, there's nothing like experimentation to answer some of these questions.

You could combine a dipole arrangement for the RD's with a sealed arrangment for the six's, but I don't think you'll gain as much as you might hope for.

IMO, the biggest contributor to "holographic imaging" is minimizing the contribution of the room and speaker to whats on the the recording. There are more than a few ways to skin a cat, in that regards.

Dipoles are most effective, IMO, for suppressing room interaction, in the range from 100 Hz up to 600-1 kHz. Some well known speakers utilizing the dipole principle only employ it in the upperbass/lower midrange, like the Legacy Whispers. This is a critical area for removing what is commonly perceived as "box" colorations in the bass or lower mids, but which is more complex, and due not just to the box, but the interaction of the box and room placement. (I think we've strolled down this path before).

Above about 700 Hz, dipole behavior becomes more complex, and begins to resemble a combination of two infinite baffle speakers with the rear wave reflected back off the room walls. This can make for larger sound field, and more widely distributed sound field, but it probably *won't* result in pin point imaging. The ear is dependent on the space clues and room acoustics on the recording- to the extend that the speaker system and playback room substitute their own "signature", the original acoustic will be diluted.

As Thomas notes, a large dipole system in rooms the size of his family room are probably not practical, on several levels. Here, I think either a smaller dipole system, or a carefull positioned monopole might work better. With correct positioning and suitable room treatments (see Thomas's posts on DIY treatments for some hints) the room contribution with a monopole system can be minimized. *

This is the approach I'm going to pursue for my RD5 project; we'll see how it works out.

* An example of the striking effect of room treatments can be observed in Thomas's room, if you start by the front entrance, speaking continuously and listening to the sound of your voice, and how it changes when you enter the main HT/living room at the front where the drop down screen is located. You can really appreciate that by continuing the test, walking back and forth between the entrance foyer and the HT room. It sounds odd to almost have an anechoic room interaction compared so quickly to hearing the normal wall reflections, but it illustrates how strong the normal room signature is... the brain is a marvelous DSP and can filter a lot of that on the fly, but elminating it gives you a lot more of a window into the system.

Of course, there are some, like Bose, who would use the room/speaker interface in a way to completely impose a consistent signature on all playback (Direct/Reflecting speakers, anyone?), but this certainly isn't a path to sonic holography, more like sonic mush and blandness, at best).

Best regards,

A jet lagged Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

Dipoles are most effective, IMO, for suppressing room interaction, in the range from 100 Hz up to 600-1 kHz. Some well known speakers utilizing the dipole principle only employ it in the upperbass/lower midrange, like the Legacy Whispers. This is a critical area for removing what is commonly perceived as "box" colorations in the bass or lower mids, but which is more complex, and due not just to the box, but the interaction of the box and room placement.

So, dipole is best for frequencies up to where you'd cross over to the ribbons; therefore not much use in dipoling the ribbons, but much to gain by dipole mounting the woofs. How much relative SPL loss from dipole woofs versus monopole?

Tequila is good for jet lag.

[Jack Gilvey]

There are more than a few ways to skin a cat, in that regards.

What is it with this site and the hatred of cats?


As regards dipole bass/sub, might it make the most sense to cross over to a monopole below the lowest room-mode? I sense the most improvement in the bass guitar range, 40Hz and up.

[ThomasW]

Hank

I'm sure that Jon appreciates the Tequlia info, but since he flew in from England on Saturday and left early this AM for a week in Minnesota it may be of limited value

I'd suggest building either all dipole or all monopole.

Those building with 'smaller' woofers or a smaller number of woofers should probably go monopole. Free-air mounting limits the power handling to the excursion limits of the suspension, not the thermal limits of the VC. An example of this is the PE website where they lower the power handling of their new IB woofer from it's 'normal' 350 watts, down to 140 watts for free-air mounting in the real world. This is because the driver in free-air will reach excursion limits of it's power handling long before it reaches it's thermal limits.

Jack

Not sure. The amount of driver displacement and the contributation from boundry loading will have some impact on the decision. Seigfried uses a sealed box below his dipole woofers and he uses EQ on the dipole woofers. When I get the Adire DPL-12"s I intend to make a baffle with 6/side to see what happens. When that's done I can probably better answer your question

Any attempt to have a pure dipole sub will require a ton of EQ and a lot of driver displacement, and thermal power handling. The real Legacy Whisper design tries to do this with 4-15"s/side and a pretty complicated dedicated EQ box. The ones I heard at one of their 'roadshows' need the augmentation of a true dedicated sub.




theAudioWorx
Klone-Audio

[Jack Gilvey]

When I get the Adire DPL-12"s I intend to make a baffle with 6/side to see what happens. When that's done I can probably better answer your question

You never do anything halfway, do you? I look forward to your views/results. I guess you'll do a big, flat baffle at first, or do you have something more intricate in mind?

[Hank]

Thomas, help me out here. Jon's comment was that dipole configuration makes its contribution of minimum room interaction and elimination of the "boxy" sound we abhor, in the 100 Hz up to 600 - 1kHz range. Since you guys recommend a 600 - 700 Hz crossover to the ribbon, why do the ribbon dipole? Believe me, I'd rather do that for ease of construction. It would be nice to sandwich two 3/4" MDF sheets and have a big flat panel baffle with no "cabinets" surrounding the back of the drivers. Those half-round plywood forms as edges.

[ThomasW]

Jack

Halfway....no way! Wretched excess is our motto :B

I'll start out with a even larger version of the black prototypes. A 4-way dipole. Now of course this will be HUGE and heavy. But I'm curious as to what it will do. Since I have no place to use such a big baffle, I plan to experiment with a few of different configurations, including the Linkwitz design.

I'm also wondering if using drivers with such a low Fs-16.3Hz would make any difference with the performance of the big IB (probably not but it's only a days work to put them in).

Hank

Jon answered your question in his last post. He's not advocating using a dipole ribbon. He stated there are reasons for making it monopole. And that having the dipole vs monopole will result in a different form of imaging.

I think something that maybe adding to people's confusion is that there is a tendency to think that Jon and I are 'talking with one voice' or 'speaking as one person' with regard to speaker design. The reality is that Jon and I actually have quite different 'tastes' in speakers. To the best of my knowledge he's never owned a dipole. So the Arvo design will be his first. Now he of course assisted in building of the Whisper klones, but he didn't run out and build a pair. The same is true with me. I had the SLAMM klones at my place for months but never listened to them unless Jon was in town.

With a 600-700Hz XO point, I don't think it's a good idea to mix dipole and monopole. Others think that it's ok. This is where it becomes a matter of personal preference. There is no right or wrong when it comes to personal preference

These personal preferences are why I make soooo many prototypes. Frequently I think that one design will be better. I pow-wow with Jon about the physics of the design and then build it. But after making the prototpye I find out it doesn't perform as expected. So a lession learned, we then develop something else.

The one thing that's a given, is that everything we do starts off as an experiment. If it works, then great. If it fails no harm done, all that's lost is time and some cash. Eventually we get it right, no matter how long it takes. Witness the M8a-MKI-MKII-MKIII-MKIV projects as an example of this process.




theAudioWorx
Klone-Audio

[Hank]

Jon stated that either a smaller dipole or a carefully positioned monopole woud be better for a smaller room. After that, he said that's the approach he's going to follow for his RD50 project. So which one does he mean?

Thomas, good clarification point about you two Grand Poobahs not speaking with one voice.

I could build an all-dipole panel and if the dipole ribbon didn't work out, it would be easy to add a long rectangular box to the back of the panel, covering the ribbon, add fill and thus change it to monopole.

[ThomasW]

Jon's going to build the monopole design.

Given the little time and effort required for the dipole I'd suggest trying one to see if it will work in your room.

IMO the larger B&G planars have a weird mounting set up. So making a prototype dipole would be would give you a chance to experiment with that as well




theAudioWorx
Klone-Audio

[Hank]

Okay, I'll bite. What do you mean by a "weird mounting setup"?

[ThomasW]

It's a pain to try and explain online.

The side mounting flanges are at one depth. Then there are areas at the top and bottom of the middle section that are at a different depth.

The side flanges have pop rivets that hold the speaker together. The front of the flange has the head of the rivet, the back side has the expanded part. So you end up having to rear mount the speaker and route 2 different depth as a result of the construction.




theAudioWorx
Klone-Audio

[Hank]

The problem with building speakers and trying them to see if they marry up well with my room is that my room will change. I'll sell my house within a couple of years and buy/build a smaller house, whic may be my last house. Floor plan to be chosen based on guess which room This reminds me of the guy who published a nice speaker design/buillding article in speaker builder - he designed for a response that had anomolies that were the mirror image of his room response anomolies, so the resultant in-room response graph was smooth. Maybe I will build a speaker to acoustically "fit" my room some day, but my preference is to build spekers that are fairly flat and then tweak whatever room that they are destined for. So, the design criteria I can cross off the list right now is: "how does it sound in my room?"

The NEO 8's have the same pop rivet construction and in assembling the Alpha LS's, I checked the rivets and on the back side of the NEO's, the expanded rivets were at varying lengths. I filed down the extra-long ones (easy since the rivets are aluminum) so that they would lay flat on the recessed "rails" that I had routed. I laid long strips of mastic (P.E. #269-300) in those recesses and then laid the NEO's on the mastic and attached them with screws from the front. The combination of filing the rivets down evenly on the back of the NEO's and the mastic strips made for an even, level line of NEO's.

[ThomasW]

Hank

That's an interesting approach to mounting the Neo-8's. I hope that some felt material was applied to the front of the baffle to smooth the transition between the rough areas of the mounting flanges/mounting screws/pop rivets and the baffle board itself.

The usual practice with any of these planar drivers is to rear mount them to obtain the smoothest physical transition between the baffle and the planar. It's a similar idea to flush mounting mid-woofers to avoid diffraction effects from the edge of the driver frame.

The larger B&G's planars really need to be rear mounted. The drivers are quite deep as a result of the thickness of the magnets. And the front of the metal 'horn' should be flush with the front baffle.

The PE mastic has a tendency to harden over time. As a result drivers can end up glued to the baffle.




theAudioWorx
Klone-Audio

[Dennis H]

Hank, how did you seal the tops and bottoms of the Neos where they meet?

[JonMarsh]

There's no denying mounting some of the planar drivers can be a bit of a chore due to their construction and mechanical configuration.

With the RD50, I expect to have to fabricate a panel assembly upon which the RD50 will be rear mounted; this assembly will then be front mounted in the cabinet. I'm still pondering materials and techniques to use.

The first LF configuration to test has been defined; due to the limitations of efficiency for the RD driver (88 dB nominal sensitivity) the 8 MCM drivers will be configured in two series strings of four, wired in parallel. Each series string will be the equivalent of about 89 dB per 2.83 VRMs input, with a minimum impedance of about 24 ohms. Two strings wired in parallel should add 6 dB of sensitivity, of which 5-6 dB or so will go the way of all things of the flesh in the baffle step correction and crossover insertion losses, taking it back down to around 89 dB - with a nominal input impedance in the midbass of no less than 12 ohms. Should be a real pussycat to drive.

If wired in sets of two in series and all paralleled, we could have wound up with 94 dB sensitivity after baffle step comp, but this would swamp out the RD driver.

At this time it's planned that the two sets of four drivers will each be in their own 100 L sub enclosure ( 4 drivers per), and with a single 4" ID port 17-18 cm long, maximum port velocity (in the mid 20's) will be safely in the comfort zone, under 18 M/s.

Now I just have to find some time to cut some wood... I've only been in the office in the US 1-1/2 days in the last month and a half, and leave for Germany the end of next week... jeeez! This is too much like working for a living!

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

Thomas, I routed a recess into the MDF, per the plan, so the NEO's faces are flush with the baffle. I hate to hear the bad news about the PE mastic hardening over time. I thought I'd found the perfect replacement for the foam gasket tape from Home Depot, which I really don't like - it has very cheap adhesive. What do you use?

Dennis, the Neo's are butted against each other per the plan and I don't think there's any detrimental effect from whatever microscopic gaps there may exist between them.

Jon, sounds like a plan - why two separate mid-woof enclosures?

[ThomasW]

Hank

I now use closed cell foam for everything. Also I found some nice foam tape at Ace Hardware. I'm not concerned about whether the adhesive has much strength. As long as it holds the tape in place for mounting the driver that's all I need.

Unless the woofer's back wave is isolated from that of the planar, there will be cancelation between them. That's why Jon's using separate enclosures.




theAudioWorx
Klone-Audio

[Hank]

Thomas, I didn't make myself clear - sorry. I've always used the closed-cell foam weather strip. The problem with the adhesive, at least on most rolls I've seen is that it is messy and comes off easily, so it gets on fingers, frames, baffles, etc. That's what I meant about low quality. I guess I'll go back to it and toss my box full of PE mastic. Should I tell the designer from the south of France that all his NEO 8's and mid-woofs are now glued to his baffle forever?

Regarding my question about Jon's plan to enclose/monopole the mid woofs, I understand completely the need to isolate their backwave from the ribbon. I was asking why TWO separate enclosures rather than one for all eight drivers.

[ThomasW]

Hank

If you want to use the mastic then kill some of it's adhesive properities by rubbing Vasoline on it before putting the driver down.

As for the fellow in France, ignorance is bliss.........




theAudioWorx
Klone-Audio

[PMazz]

rubbing Vasoline on it before putting the driver down.

That's getting a little personal, isn't it?

Pete

[Hank]

"...ignorance is bliss."
Ain't it, though?

Pete, we're trying to keep this on a high plane. Thomas tries to help me save my box full of mastic and you have to go and take it down into the gutter - nice move! :LOL:

Speaking of vaseline, an old laminate installer's trick was to keep a jar on hand and rub a line of it where his laminate trim bit bearing surface would ride, thus protecting the laminate from marks/burn.

[JonMarsh]

Regarding my question about Jon's plan to enclose/monopole the mid woofs, I understand completely the need to isolate their backwave from the ribbon. I was asking why TWO separate enclosures rather than one for all eight drivers.

Well, it means that I won't have to drill holes ventialating at least one set of cabinet panel braces! (say, in the center). Plus, it's easy to analyze the performance of one set of 4, then extend to a second set in parallel (I'm nothing if not lazy....).

As Mao once said, (or said something similar), let a thousand flowers of thought bloom... i.e., to each their own.

My initial concept was four individual isolated sub enclosures (with two drivers each), just to have plenty of panel bracing. Looking at the tuning options of shared volume and port size, I finally figured I like combining to two sub enclosures, and reducing from 4 3" ID ports to two 4" ID ports- costs less, less work, just as filling. Still just one big cabinet, it's just how it's subdivided and braced internally.....

As per previous discussions regarding baffle step effects and planned crossover frequency, front baffle will be 16" wide, overall cabinet depth planned at 20". Max output per cabinet looks to come into the 116 dB range. Should do the job.... and it will actually be less expensive (and I hope easier) to build than my X1 Klones.

-Jon

First




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

16" wide x 20" deep....this bad boy is still going to be BIG. The performance had better garner Stereophile, no...The Absolute Sound type adjectives to motivate me to install those monoliths in my home :? :roll: I have a possible customer order for a pair of tower cabinets, so I may have to earmark some of that money for a pair of RD50's

[JonMarsh]

Absolute Sound adjectives? Not spoken here! :P

We go for the boys who at least try to do some good measurements, so let's stick with JA and Stereophool! :LOL:

Also, remember, my cabinets will be only 58 - 60" tall. Perhaps sitting on a 2" plinth; probably spiked (add another inch?). Somewhat petite compared with some of the "competition", whether from the south of France or elsewhere. I'm hoping the depth isn't really an issue; I find frontal area and height to be the "biggies".

One could always make alterations to height and width ratios, and remember I'm gunning for in room bass flat to the mid to high 20's; if you plan to use a sub with these, they could be retuned/detuned and shrunk in cabinet volume by 25 - 30%. Remember I want a fairly full range speaker for amp evaulations and the like.

What isn't particularly negotiable for this first one is the front panel width; I want it to support the RD50 all the way down to the crossover frequency I'm using, which means I'm fairly committed (at least in theory) to a 16" width. Then baffle step compensation is only required for the LF line array. If I tried to go with the narrowest possible front panel (which really couldn't be any less than about 14", given the driver sizes), this would move the baffle step transistion up to about 800 Hz, and would probably complicate the RD crossover. I'll know for sure when I actually get to measure a test cabinet.

Another point not decided is the crossover- it may be a conventional 4th order L-R, or I may use my high slope crossover which mimics an L-R 8th order to minimize driver interaction in the crossover region. In practice I'll probably try both and see if I have a preference based on measurements and listening. The additional component count for the latter is quite minimal - one additional reactive component in the HP and LP.

This weekend I start cruising for 7-11's to knock over to save up my pennies for a pair of RD50's. I also need to sweet talk my honey about keep a saw in her garage - wish me luck! :LOL:

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

"Oh Lord, won't you buy me, a color TV?
Dialing for Dollars is Trying to call me"
And, Lord, don't forget Hank, he needs some help too
It's expensive ribbons they've talked him into.

(Sorry Janis)

Oh no, I'm starting to understand this far out stuff.

Jon, maybe it's not the presence of the saw in her garage that's the problem - it might be the MDF dust coating on her car :roll:

[JonMarsh]

Ya think it might be easier if I just stored a couple of my motorcyles in her garage instead of the saw? And put the saw in my own garage? The bikes don't generate any MDF dust, but then I couldn't use them to rebuild her stair bannister and do some other home improvement honey do's for her...

Started work on the CAD drawings on the train last night going home... this means I'm getting serious.... (and the 16 MCM drivers in my closet don't?

Hey Hank, those lyrics are preettty good, but as every one tells me, don't quit your day job yet....

-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Jack Gilvey]

Hank only writes songs of great social and political import.

[Hank]

Yeah baby, I was like, makin' a statement, ya know.
Actually, my musical talent is in my clarinet. Last night the Wurst Band did our last gig of the September season at Scholz Garten - even had a TV station film us for 45 minutes for special
http://www.scholzgarten.com/ I try not to miss a Wurst band Thursday because Scholz'a gives the band all the free beer we can drink!
Here's my serious group that requires practice - the ASB is one of the best civic symphonic bands in the country:
http://www.asband.org We be jammin' in Austria in 2004.

[JonMarsh]

Are there any recordings available of the ASB? One's you'd recommend?


Making slow progress on figuring how this all going to go together.

Found a source for a 1-1/2" roundover bit, at about $53.

Also researching veneer suppliers, found a pretty good one at

http://www.oakwoodveneer.com/

Good, as in wide selection, including some of the more rare and exotic materials. Prices are reasonable, but not cheap. One of the options I'm considering for finishing would cost almost as much for the veneer as for the ribbon drivers, but then when you talk about putting something this big in your home, you do want it to look nice. We'll just have to see what happens- maybe I'll cheese out instead!

Anyone want to contribute their favorite ideas for good lucking low buck veneer finishes? (wood plus finishing techniques?).

I'm heck on wheels for designing electronics, but the last wood veneer speaker I built was in the 70's- and they looked pretty dang sharp, but it was just a nice walnut finish. I'm leaning towards some of the redder woods at this time, but I'd like something somewhat figured on a speaker this large, which may leave out cherry, for example, as it tends to be somewhat bland.

Comments?

-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[PMazz]

Try these too:

http://www.tapeease.com/products.htm

http://www.wood-veneers.com/veneers.htm

There are some new lines that a rep dropped samples off to us. They are "man made" veneers that are combinations of thin sliced wood that are glued up and then sliced into veneer. Some neat looking stuff. I'll have to get back to you on them, tho.

About the only thing we use for finishing is lacquer. Spraying 3-4 coats in an hour is the only way to fly. To me, there is nothing like the clarity and feel of a lacquer finish, but you really need to spray it.

Pete

[Dennis H]

Found a source for a 1-1/2" roundover bit

Yikes, BE CAREFUL with that sucker Jon. I've only used bits that big in a bench shaper that weighed several hundred pounds. I'd be nervous to try it with a handheld router but if I was determined to do it.....

Firm grip on the handles. (imagine Arnold flexing) Even the starting torque will be substantial and if it kicks during the cut, you're toast.

Trigger on-off switch (not a toggle) so it will shut off if you lose control.

Make several passes, gradually increasing the depth.

Friendly advice from a former builder/cabinetmaker. (worth exactly what you paid for it.)

[JonMarsh]

Hey, no kidding, why do you think I've been working out the last six months but to get ready for this project?

Seriously, Dennis, that would be the last pass in a series of passes with increasing size bits; I expect ot have an MDF front panel depth of 2-1/4" built up; it will be routed on the back side for relief for the drivers, also. The front panel's going to be the biggest part of the work in some ways, between the arrangements for the RD panel, roundover for the sides, and relief for the woofer holes. I don't plan to use flush mounting for the woofers because there will be a hard felt matching interface to the RD driver, and at the frequency range the midwoofers are used, diffraction should only occur off the baffle edge.

Of course, this is just all "theory", and as they say, no battle plan survives contact with the enemy.... hopefully I won't go through as many iterations as I did for the M8 bookshelfs, though! :LOL:


-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

Are there any recordings available of the ASB? One's you'd recommend?

Yes, and I'd recommend a couple - last November's concert with "Ahab", a piece with narraton from Moby Dick and the symphony, "Lord of the Rings", which we premiered in Chicago a few years ago. Also, last Feb's concert, Shades of Blue and Jazz Too. I'll see which I've got an extra or two. Our group, while not professional and no studio recordings, is prettty darn good and our recordings make for THE dynamic range equipment test

Found a source for a 1-1/2" roundover bit, at about $53.

I trust that's MLCS that I recommended to you. Also, you are NOT planning to use it in a hand-held router. That's not a question, it's a statement, or if you like, a direct order. I use my Freud 3 1/4 HP router in my router table. Buy or build a router table. Any questions? I want you to live long and prosper so I can continue to learn from you just as the young caterpillar learns at the feet of the guru.

Also researching veneer suppliers, found a pretty good one at

As a reference, I checked their price on Padauk, and even though they misspelled the word, their price is exactily what I paid Tapeease for the Padauk I veneered on the towers for that guy from the South of France. I use Tapease now - nice guy, and as you know, nice guys are scarce these days.

Anyone want to contribute their favorite ideas for good lucking low buck veneer finishes? (wood plus finishing techniques?).

Jon, I'm not a pro like Pete, so I don't have a spray booth and equipment required for pro spray finishes, but even if I did, my favorite finish would still be my version of hand-rubbed Danish oil. It's only affordable if you are doing a DIY project or if you have a well-to-do client that really appreciates the finish. It results in a Frence Polish finish and is very labor intensive. Send me an e-mail if you are curious.

It appears you're getting serious about this little ribbon-based line source. Heh-heh-heh. Let the games begin!

[Brian Bunge]

And Hank, please don't forget who informed you about Tape-Ease...

[JonMarsh]

Hi Hank,

You've got mail- I'm all ears (sometimes with some elbows and two left feet thrown in).

The router table is part of the plan, along with a new saw locally (when I can, I just use Thomas's shop, but I don't get out there as much as I'd like, and moving the finished product back to CA is a real hassle- just do a search for "rendevous in the desert", or ask Thomas- sort of a Hunter S. Thompson thin, Fear and Loathing in Wendover UT/NV ).

I also had another hot flash this weekend, and it occured to me that rather than use veneer over baltic birch and MDF, I might use solid oak over baltic birch ply and MDF, which would make Thomas happier re the overbuilt superstructure, (stiffness), wouldn't probably be any more expensive than nice veneer, and would be relatively straight forward to finish. Have to use a pore sealer, and maybe do some tests on pieces with different stains and oils- heck, I have had good results just with my old time techniques using Watco. Inputs are welcome.

Just checked my piggy bank this weekend, and after paying bills I may have enough left to pay my daughters tuition and books for next semester and order a set of RD50's.... don't know what the leadtime is, as ThomasW got the last set of RD75's at PE, and I don't know how long it takes to get them in. I have negotiated some temp space for a saw and router table.

Any opinions on router tables? This one looks pretty good to me, and is available in a model with a Port-Cable plate, to work with my "big" router. Only $160.

http://www.rockler.com/ecom7/findprod.cfm?&DID=6&User_ID=9804105&sku=894

This looks even better:

http://www.triton.net.au/products/rt.html

Unfortunately, it's Australian....

And there's the MLCS, which is a bit more expensive.... as in 2X+

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/routabl.html

So many questions to consider....


-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[sfdoddsy]

Just a quickish question on dipole subwoofing. One of the advantages of dipole subs is supposed to be the reduced room interaction compared to monopoles.

Does this advantage still hold true if the monopole sub is EQed to reduce room modes, via a BFD or other such system.

Cheers

Steve




Steve's DIY Dipoles

[Hank]

Jon, if you're talking about thick solid oak, like 1/2" -3/4", I'm not sure that's a good plan. Remember, wood moves and thick, large pieces of wood move a good bit. That's the other reason table tops are built with several smallish edge-glued pieces that are layed with alternating growth ring orientation (the other reason is cost and a limit to the size of a plank available in a species). If you want to cater to ThomasW's fetish for exotic cabinetry, why not do a baltic birch MDF sandwich with a constrained dampening layer, say the sheet stuff from PE? And I think you'll find that oak and maple veneer would be quite a bit less expensive than solid oak. With veneer, you'll probably get better looking grain. If you get into staining, consider using dye. It goes on easier and penetrates deeper. Maybe I'm just unlucky in stain as in cards, but I have a heck of a time getting stain to "stain" evenly. Brian (the Georgia kid who follows me around the forums trying to one-up my posts, as in the one above) has done some beautiful cabinets in maple veneer the he dyed with Behlen SolarLux. It's on the Woodcraft web site and listed under stains, rather than dyes, but it is actually a premixed dye. Brian does good work: http://www.rutledgeaudiodesign.com/

Router tables: as they say in audio, I haven't run double-blind tests or looked at very many. I built one from plans from Jointech. It's the one on their home page: http://www.jointech.com
BTW, the Jointech SmartFence is THE router table fence - wouldn't trade mine for anything. My one advice is to get as large a surface table top as you can. Pushing a 42" tower cabinet across a small table is not a one-man job unless you have infeed and outfeed tables. That Rockler looks like the way to go for a good size inexpensive table.

You might want to buy some small pieces of veneer locally to try different finishes and see how they look. I've got a box of 10"x12" birch ply veneered on both sides with different species of veneer - about 20 in all, and they're a great reference. I want to do something in block mottled makore, figured sapele, quilted bubinga and others - there's some gorgeous wood in the world.

Rember: a man can't have too many tools If your girlfriend understands and accepts that, she's a keeper.

[Brian Bunge]

Jon,

I have the Rockler table and really like it. The only real reservation I have is that it's a real bitch to adjust the fence if you need to cut a dado in a board. You have to have the fence completely parallel to the front edge of the table. Since the ends of the fence can move independently of each other that can be difficult. Once I set it up to cut dadoes in the side of some A/V-1+ cabinets I for bracing I scribed a line on the table along the fence to make future setup easier. Hank's fence system looks to be much easier to use and I may still go that way one day. But for small projects or for doing rounded edges, it works just fine.

Brian

[Hank]

See what I mean about Brian-boy? :roll:
BTW, he just returned from CEDIA all educated and fired up. Quit his day job to get into the install biz. I predict that he'll do well.

Jon, for the lowest labor content and quickest finish, polyurethane is hard to beat. I discovered a high-quality water base poly made by General Finishes. It won a woodworking magazine comparison test as the best water base poly. It really does brush on very well:
http://shop.woodcraft.com/Woodcraft/product_family.asp?family%5Fid=756&gift=False&0=de pt%2Easp%2Cdept%5Fid%3D10000%26Tree%3D%2CDepartmen ts&1=dept%2Easp%2Cdept%5Fid%3D1042%26menu%5Fid%3D% 26Tree%3D0%2CFinishing&2=dept%2Easp%2Cdept%5Fid%3D 4043%26menu%5Fid%3D%26Tree%3D1%2CVarnishes&Gift=Fa lse&mscssid=DD4692DFB85D4F63BDD786908AA6118F

edit: I don't know what's wrong with that link. The product is on the Woodcraft web site in the varnishes area, under "Environmentally Friendly Water Based Finishes"