Wavecor Ardent Journal - the first Builds

[TEK]

I guess there will be a nice partlist with both drivers and crossover parts when the perfect crossover is done, so that we copycats may just steal off all the butiful work you folks are doing... ops:

[JonMarsh]

I guess there will be a nice partlist with both drivers and crossover parts when the perfect crossover is done, so that we copycats may just steal off all the butiful work you folks are doing... ops:

That is exactly the plan- a BOM just like the Isiris one with some options on parts in the network (for example, Jantzen Superior Z caps for the tweeter OR MR Clarity for those wanting, well, a little more clarity? :W That's intended as a joke, but the price differential is 2:1 for the caps, so it's no joke. I think the Jantzens are quite good, and represent very good performance for not too dear a price. I used the MR Clarity in the first Ardent builds, and like them with the 6640, so maybe I'll go that way again.

Here's the preliminary BOM for the concept test version I've simulated with LspCAD using older measured data and different woofers:



This is NOT a finalized design, but a first pass at adapting the Isiris concept to data measured in the original Ardent enclosures, and I thought it a good idea to test it out and publish it in case I am killed in a traffic accident, because it probably would work OK, other than possibly adjusting pad resistor values somewhat.

This is an "expensive" version; one could likely justify consolidating all of those Jantzen Superior Z caps in the midrange into just some Jantzen Cross caps, for example, if money is tight, and only using the Superior Z on the treble.

[MickRS]

Man, the more I read here, the more I am stunned by the level of knowledge at this forum...

Might be a stupid question, but looking at that list, these seems like rather complex xo's. What does that do to the sensitivity of the speakers?

[JonMarsh]

Sensitivity of the speaker is determined by the driver choices for Theile/Small parameters and the desired low frequency target and box volume- all things being the same, for a given box volume, more LF extension sacrifices efficiency.

The Wavecor 8-3/4' woofers were selected for their LF performance in a relatively small volume- and that requires a higher mass cone, different Qts parameters, and this sets a relatively low efficiency- more like the traditional acoustic suspension designs of the 70's and 80's.

From Wavecor's own simulations, a single SW223BD01 will offer a variety of curves depending on enclosure volume:



At 20 liters, half of the original Ardent enclosure volume, we have a pretty nice characteristic considering this is without the typical in room boundary lift at lower frequencies- two of these in 40 liters wired in series giving a net 8 ohm resistance should work it well, with the same nominal acoustic sensitivity (gain 3 db from second driver, lose 3dB from doubled load impedance.

Modeling this driver in Unibox is straightforward:





and unlike ported designs with their hangover and ringing, the modeled step response of this sealed alignment is critically damped (a concept used by Avalon for all their early systems designed by my friend Charles Hansen), and has very good step response. (I.E., clean, tight, well defined low frequency behavior)



The trade off is lower system sensitivity, and this requires some padding of the midrange and tweeter. Refer to the previous page of posts in this thread for concepts behind the crossover transfer function. This is actually a fairly low component count for a high performance three way crossover...

[JonMarsh]

GF has confirmed delivery of pallet- and they came earlier than the quoted time, so she got home only 5 minutes ahead of them!

I'll be going straight there after work, to unpack and put away- thanks again for all your effort!

[wkhanna]

Sweet!

[benthe8track]

GF has confirmed delivery of pallet- and they came earlier than the quoted time, so she got home only 5 minutes ahead of them!

I'll be going straight there after work, to unpack and put away- thanks again for all your effort!

Awesome! I hope they got there without a scratch.

[JonMarsh]

Took a chance and left a little early from Cupertino, but it worked out as traffic cleared out a little earlier yesterday- often happens on Mondays for reasons I don't understand- same thing WON'T work on a Friday!


Well, this isn't exactly like one of those articles unboxing a new computer or tablet just released, but for me the feeling is quite similar...

The pallet arrived in fine condition...





If you're thinking I did a fairly reverent unpacking job on these, you would be correct...





One step at a time...





And off loaded from the pallet, next to GF's Porsche 356...





Now they're ensconced in the official "man cave" at GF's...





Where they'll be ready and waiting for me this Saturday.



Hat's off to the "Winnipeg Wrecking Crew" and the fantastic job they've done getting these cabinets together so quickly and with high quality!


If this were a normal working situation for me instead of this special customer project since last summer, I'd probably be taking vacation on Thursday and Friday so I could dive into these right away...

As it is, it's a bit weird, because we were supposed to be having a team of 2-3 guys arriving from Munich yesterday evening, and I just got an email about 3 AM this morning that they'd put off their trip until next week- this won't help the critical customer schedule, but apparently one of the customer engineers was in a serious car accident this weekend (as was our own local firmware guy) so the working meetings were postponed.

So the transmission is in neutral the rest of the week, and next week will be very unpleasant trying to catch up.


I can see a number of steps needed next before measurements- getting out my DeWalt table saw and trimming the front panel just very slightly, as DAR47 warned me; and since I have extra lead sheet and Cascade VB3 and heavy felt ordered for the Isiris update, I'll be lining the midrange cabinets and installing the Cardas SE-11 cable first, then gluing up the front baffles. I'll use one of my older Ardent base platforms for doing the initial measurements, as I have an easy way to get the driver leads out the bottom for test connections.

I also should be preparing the grilles right now, if I want to include the effects for driver measurements and crossover development. Thinking about all this, I expect that I'll be very busy getting all of these things done this weekend, and not get to the measurements until the following weekend.

I'm just undecided about whether to try to do this work at GF's, or take them home and do it there, and bring back to do measurements on one. That may be the more sensible plan, as there's a lot of tools and materials I'd have to take to her place. Have to discuss with her and see.

[dar47]

That's a relief :P

Did you peek inside the mid caps? The rest of your goodies are in there.

[JonMarsh]

That's a relief :P

Did you peek inside the mid caps? The rest of your goodies are in there.

I figured you guys had stashed stuff away some place like that- but I didn't have time last night- just a little bit of soup for dinner, unpack the cabinets as you see and cart them inside to my future home office, then crashing out while GF watched one of her favorite PBS detective shows!

But thanks for the "hint"! :B

[MickRS]

Those look stunning! Bet they will sound likewise.

It's these kind of projects that are really inspiring. Can't wait to start my own project...

[JonMarsh]

Good news from at work- I'd forgotten we normally get Presiden'ts Day off (next Monday). Only problem is customer I'm working at doesn't and this may be a support issue...

If it all works out, though, I'll have more time to work on the Wavecor Ardents and get the measurements done on next Monday! this would be super! Who knows, maybe I can hack some parts from the 1st gen Isiris midrange crossover and have something to roughly test just to make noise... ;-) I'm going to order some crossover parts for tweeter section just on spec from first analysis today.

[JonMarsh]

Just tried putting an order together for trial tweeter crossovers from Parts Express- NONE of the caps or inductors from Jantzen were in stock!


Madisound, OTOH, had the Clarity MR caps in stock in the 400V versions (smaller and slightly less expensive) as well as a nice low DCR Goertz ribbon foil inductor.

Order placed, for two day delivery to GF's...

[JonMarsh]

Adam at Madisound confirmed shipment today. This is how stuff is supposed to work... :B :T

[dar47]

Wow, Jon you sound as jacked as us. :T Those guys are great when ever I have ordered from them.

Do you have time to get those baffles epoxied on before Monday? Both sets of our cabs are prepped as smooth as a babies bottom. Should have Ben's veneer on by the weekend and I've been lagging behind ordering the veneer for mine but I'll get that done tomorrow to try and keep pace. Ben is working with a guy to get some samples sprayed with different options, should be cool if the price is right? Knowing me I'm such a cheapskate I'll just brush on, but it would be nice just to rub them out after someone else sprays them.

[JonMarsh]

Wow, Jon you sound as jacked as us. :T Those guys are great when ever I have ordered from them.

Do you have time to get those baffles epoxied on before Monday? Both sets of our cabs are prepped as smooth as a babies bottom. Should have Ben's veneer on by the weekend and I've been lagging behind ordering the veneer for mine but I'll get that done tomorrow to try and keep pace. Ben is working with a guy to get some samples sprayed with different options, should be cool if the price is right? Knowing me I'm such a cheapskate I'll just brush on, but it would be nice just to rub them out after someone else sprays them.

I believe I'll have time to get the interior work done and baffles epoxied on before Monday- I'm dedicating most of this weekend to that, apart from a Valentine's dinner Saturday evening! :W I've got all my supplies (lead sheet and VB8, Cardas SE-11 cable) and additional tools collected, ready to take over to GF's Saturday morning. I've still got to pick up clamps from my storage unit. She fired up the Ryobi table saw I've been storing at her place yesterday to be sure everything looked OK and ran OK, too. By having all my supplies organized and packed in the "Really Useful Box" sets I get from Office Max, stuff is well organized and easy to transport. I love their big ones- strong, stack very well, a very good design. I buy them online direct at times too, when Office Max doesn't have the model I want locally.

What I'll be lagging on is coating them with epoxy and getting ready to veneer- but I figure my "Job 1" is to get the measurements done and confirm a crossover design ASAP so that I don't hold up you guys! (I do have all the supplies in for doing the epoxy work, so who knows- maybe I'll be working on that Monday? That would be a stretch goal...) I have a pretty substantial store of spares and odds and sods in crossover parts, so I may be able to update at least one of the old Isiris Gen1 crossovers to something that will work after some measurements and LspCAD work- we'll see.

===========================

I do see the attraction of getting a specialist to do the spraying- if the work is good and the price reasonable, that would be an attractive option. OTOH, I have my semi-portable baffle rig with explosion proof fan, and my Fuji turbine sprayer



Horrifying statistic- I purchased 105 items from Amazon in 2013, including that sprayer... that's one every three days, roughly... but getting good stuff locally is so difficult in many areas- nay, impossible! Who's my local Wavecor dealer, for example? Or handles Pentax limited series lenses?

Plus, I have my two home made turntables, designed for up to 200lb loads, which makes any spraying job much easier, so it seems I should just "Do It Myself" (DIM, as opposed to DIY?). Let's see if I can remotely do as nice a job as those Avalon guys do in the video...

Will be a little tricky setting up at GF's for the veneering work, I think I'm going to have to move my beech bench over there soon, as her bench is, well, antiquated and dilapidated. Don't know if she's willing to give it up or not-- she's using it too much for storage, too, which is not what a bench is for. I have to move at a reasonable pace lest the rate of change prove uncomfortable to her. She's gone from a former husband who was unhandy and never got anything done to a BF who is a bit of a whirlwind in her eyes. I think she mostly approves, but occasionally is uncomfortable at the rate of change. As I've reminded her now and then, sometimes you have to be careful of what you wish for... :rofl:

[JonMarsh]

All of the epoxy supplies and the veneer trim bits have arrived now. GF asked me this AM if I had a list of all the things I needed to bring over Saturday AM to get busy- I told her it was in my "cloud", accessible on phone, iPad, and Mac. She wondered if I would share my cloud with her... ;-)

Really looking forward to this weekend. :B

[BobEllis]

What a great GF, Jon!

My past ones have all just rolled their eyes when I tried to help them understand how to hear what was good about my system. The latest is showing promise. After a couple minutes of listening, without prompting she commented that she'd have a hard time listening to her B@$# radio after hearing my system. Unfortunately all the "spare" speakers I still have are in prototype (mdf) boxes that won't do in her living room. Guess I'll have to get cracking.

[MickRS]

105 items in a year...8O Are you a woman? If so, then i dont want to know what you do with that spray gun... :B

Have fun this weekend! We'll be watching you...

[JonMarsh]

What a great GF, Jon!

My past ones have all just rolled their eyes when I tried to help them understand how to hear what was good about my system. The latest is showing promise. After a couple minutes of listening, without prompting she commented that she'd have a hard time listening to her B@$# radio after hearing my system. Unfortunately all the "spare" speakers I still have are in prototype (mdf) boxes that won't do in her living room. Guess I'll have to get cracking.

Yeah, even if we don't have to deal with WAF, there still is GAF!

GF likes the Isiris, has nick-named them Bonnie and Clyde, and has a "shawl" over Bonnie, because occasionally when it rains really hard out here in Northern CA, she can get a leak in the roof of her family room (it's not a drywall ceiling, but a wood beam A style ceiling that's underlay's the roof structure.

She's cool with the Wavecor Ardent's since I've shown her the veneer and what an Avalon Indra in curly maple looks like; anything close to that will be fine with her.

She plays piano and acoustic guitar, and is intrigued with the idea that we could plug her Yamaha arranger piano into the Wavcors, or use them for recording and playback for the piano and guitar in the living room (now designated the music room anyway- my guitars and organ are going in there, too).

[JonMarsh]

Nah, I'd make a heck a ugly woman, 6'2", 220 lb, reasonably wide in the shoulders-

It's just that there is so much stuff that I buy which I find is really hard to source locally in the SF East Bay, for example- I don't think of myself as having an esoteric lifestyle, but...

So, looking just at recent Amazon purchases since the beginning of the year-

• Out of print books used in a SciFi series I was interested in
• Book of all the guitar parts in Eric Johnson's album "Up Close" transcribed to sheet music
• Specialty flashlight using Cree high performance LED's
• Three CD's featuring Beth Hart and/or Joe Bonamassa (go try to find those in a local retailer!)
• CaseCrown Omnia Case carbon fiber for iPad Air
• 3 Razer Orochi Mobile PC Gaming Mouse
• Franklin Sensors Pro 710 Precision Stud Finder
• Mugs, bowls, and bread and butter plates for Mikasa Italian Countryside china
• Jarrow Forumulas Famil-E soft gels and five other Jarrow formulas (about 2/3 to 1/2 the price of same vitamin through local health food store)
• ful Side Car iPad Messenger bag, black
• Microsoft Windows 7 Home Premium, full version (to be installed with Parallels 9)
• Jazzmenco (La Vienta) CD
• Office Mac2011 Home and Business
• Mikasa Italian Countryside 45 piece dinnerware set, service for 8
• Adobe Lightroom 5
• Philips SOnicare HX6921/02 Pro electronic toothbrush
• Bang Bang Boom Boom (Beth Hart), and Seesaw, Beth Hart with Joe Bonamassa
• Master Handbook of Acoustics

This just isn't the stuff which local shopping where I live in the East Bay is possible...

Hey, Amazon will even ship me the GOOD lacquer with high volatiles which theoretically one isn't supposed to be buying or using in CA... :B

I hope it will be an interesting weekend- the customer site I'm working at is like a kicked over hornets nest today, and we're getting complaints about having Presidents Day off (holiday for the company I work for), and there planning on working Saturday already... this isn't looking good.

[benthe8track]

What I'll be lagging on is coating them with epoxy and getting ready to veneer- but I figure my "Job 1" is to get the measurements done and confirm a crossover design ASAP so that I don't hold up you guys! (I do have all the supplies in for doing the epoxy work, so who knows- maybe I'll be working on that Monday? That would be a stretch goal...) I have a pretty substantial store of spares and odds and sods in crossover parts, so I may be able to update at least one of the old Isiris Gen1 crossovers to something that will work after some measurements and LspCAD work- we'll see.

===========================

I do see the attraction of getting a specialist to do the spraying- if the work is good and the price reasonable, that would be an attractive option. OTOH, I have my semi-portable baffle rig with explosion proof fan, and my Fuji turbine sprayer



Horrifying statistic- I purchased 105 items from Amazon in 2013, including that sprayer... that's one every three days, roughly... but getting good stuff locally is so difficult in many areas- nay, impossible! Who's my local Wavecor dealer, for example? Or handles Pentax limited series lenses?

Plus, I have my two home made turntables, designed for up to 200lb loads, which makes any spraying job much easier, so it seems I should just "Do It Myself" (DIM, as opposed to DIY?). Let's see if I can remotely do as nice a job as those Avalon guys do in the video...

Will be a little tricky setting up at GF's for the veneering work, I think I'm going to have to move my beech bench over there soon, as her bench is, well, antiquated and dilapidated. Don't know if she's willing to give it up or not-- she's using it too much for storage, too, which is not what a bench is for. I have to move at a reasonable pace lest the rate of change prove uncomfortable to her. She's gone from a former husband who was unhandy and never got anything done to a BF who is a bit of a whirlwind in her eyes. I think she mostly approves, but occasionally is uncomfortable at the rate of change. As I've reminded her now and then, sometimes you have to be careful of what you wish for... :rofl:

I looked at that Fuji sprayer and it seems to be really well reviewed. I would prefer to spray it myself if I had the chance it just won't be warm enough here in time (high of -14 today so that's exciting). Paying someone to do it puts me at their mercy. I think I talked to everyone with a spray gun in Winnipeg and the guys doing the samples talked the talk so hopefully it works out.

Going to try to bookmatch the veneer today (if it's flat enough) and once the raw is done I expect the PSA to go quick. Hopefully get that into the paint shop next week so I can have some downtime and finishing packing up my place, need to be gone by months end and so far I have packed 0%.

[JonMarsh]

Months end? Thats going to be tight, but then at your age, you probably have a bit smaller footprint...

We've been planning that I would move into GFs (20 miles away) since early last year, and with everything else going on, plus the zoo at work, the progress on that is slow, though momentum is building, what with the storage racks installed in the garage, the generator and transfer switch (don't want something like an earthquake to slow down the DIY projects!) things are moving along. . In a month or two we'll get to putting in a concrete pad for a storage building in her copious back yard.

Here, we've had a warm spell- overnight lows the last few days were around 50! Can you imagine?!

[JonMarsh]

Most of today was spend being the moving man! Just moving tools, supplies, parts, etc. around took up most of the day (plus fielding a couple of calls from work). But everything is setup and in place for real work tomorrow- for now, it's time shortly for a delayed Valentines Day dinner!


Things are looking good- I found the goodies in one of the midrange cavities- thank you guys! and got the cabinets setup and did a test fit of the drivers- talk about spot on! :T

So here's a few pictures showing off the Winnipeg Wrecking Crew's work!











One thing I see likely to need addressing is the laser cut inside of the felt by the tweeter- that will likely generate a not so nice diffraction point, and will need to cut a bevel in it for soft felt to be exposed at an angle to the wavefront.

[benthe8track]

Oh thank god the drivers fit haha.

Yeah we noticed the felt issue too, I think the old man hit his with some sandpaper which took the crust off and it got fluffy again. Any idea how to cut it to get a nice bevel? Heh, how did it smell?
I'll have to pull out the dslr for pictures going forward, the cellphone shots look like garbage but I got the raw veneer bookmatched and applied to the backs today. It wasn't bad at all despite it being fairly brittle.

[JonMarsh]

Yeah, the laser cut felt definitely has an "aroma"! :W

I'm fresh out of ideas for some gee whiz technological way to cut a nice bevel in the inner circle of the tweeter felt- expect to just do it with a sharp knife, maybe clamping it down with something else and a suitable hole cutout.

Yeah, when we get to this stage Ben, it's time to use the DSLR's, no cell phone camera pictures from me from here on in, just my little K3 and prime lenses! :W

Especially with the veneer, it deserves more- it's going to be interesting to see how yours turn out once they're both veneered and finished.

And yeah, you guys couldn't have done the driver hole sizing any closer... it's perfect! :T

I've handled some walnut burl before, it doesn't strike me as being easy to work with in solid unbacked sheets. I've seen worse, though. I'm not expecting much trouble with my curly maple- maple quilt, now that's a bit more temperamental!

[cjd]

Isn't the best performance a non-circular felt treatment around the tweeter anyway? A simple zigzag pattern with a sharp chisel would be easy enough, expose the fuzzies, and break the perfect circle.

That said, those look incredible.

C

[JonMarsh]

You've got a good idea, there, Chris! I've done diamond slots before, which works pretty well- anything that doesn't generate a nice step diffraction at one timing. Hmmm...

[JonMarsh]

Wavecor Ardent Speaker Camp, February Edition

Getting started here this AM, a little more planning and logistics things to take care of.


Here's a pic of one of the cabinets with the drilling templates for drivers that were prepared up North... along with the tweeter mounting plate of the one I blew up when a bad input connection to my Aragon 8008X3 causes a high frequency oscillation (not the right thing to do when you have muy expensivo tweeters hooked up!)



With these drilling templates it's quick work to get the driver mounting holes done- we should probably make these available as loaners if anyone else goes this route!




After drilling all the mounting holes (and checking the square drive Visitor Messages and Private Messages screws I'd bought- too big a screw head, even for the woofers!) the next step is prepping the midrange enclosures- which is fairly easy, as the front panels aren't glued on yet (hopefully before the end of today that will be addressed!)

[5th element]

I have to say the pair of Wavecor bass drivers look very impressive like that, these are going to have some serious low end capability. Plus, if one wanted, they could always add in a Linkwitz transform to the bottom end to really give them some extra extension. Unless you wanted silly SPLs, the drivers look like they'd handle it with alomb, providing you've got the power.

[JonMarsh]

I think you're quite right about the potential efficacy of a small Linkwitz transform on the bottom end; I've done this a few times before, even in the 80's, with a close to over damped alignment and put a passive 6 dB shelving boost circuit at the input to the power amps. I'm also considering that for the Isiris, for exactly the same reason- drivers have lots to give, can handle power, and just a little more tickle at the right frequencies should be just the thing- not 1.21 Gigawatts mind you, just a tickle!

Lead sheet is glued in, and some of it clamped- this 8x stronger Loctite construction adhesive should be just the thing, BUT I've got to wait for it to setup until tomorrow- a longer setup time than I remembered. So, have to knock off early, and go do something mundane but necessary like Laundry, as well as load up part of my Marshall stack to bring over to GF's (she says she want's a demo of why I have several different guitars- yeah, I don't think she realizes what she's getting herself into. I'll use the DT50 head with the master volume cranked DOWN, though- though I suppose the VM2266 could do the same thing, the Marshall just doesn't sound as good at lower volumes as the Line 6. Plus she doesn't understand how this POD HD Pro X can interface with one or two amps, completely control the DT50 including output stage parameters, and feed a clean feed to a second amp. We don't need no stinking pedal boards... because an FBV shortboard plugs into the POD HD and provides programmable foot switches and an expression pedal.

[Steve Manning]

This what you guys are talking about for the tweeter .....

[JonMarsh]

You've got it Steve! :T

A cold chisel worked well for cutting the lead, might be good for this, too!

[JonMarsh]

Construction adhesive didn't setup very well last night because of low overnight temperatures in the garage. I brought the cabinets indoors, for the morning, then back out after things have warmed up. Now I've finished the lining work for the midrange enclosures, drilling holes and routing cables, sealing them up. GF has agreed I can bring the cabinets back inside after they've outgassed the construction adhesive a bit, and epoxy the front panels in the man cave. Too busy to post pictures right now, but by next weekend should catch up.

A lot going on right now, have guys from HQ in Germany coming in this evening, will be quite busy during the week, AND, at dinner last night, my daughter showed me her new engagement ring - since this Valentine's Day - and advised me not to make plans for June 2015! :W

And I lost another eBay bid on a Leslie 3300 cabinet, but hey, no big deal! I won't pay too much...

[5th element]

I hear you about the adhesive, I was epoxying something over the new year and actually needed to heat the workshop (which is at the top of the house) otherwise nothing much happened. Good thing it's a relatively small space.

[JonMarsh]

One baffle epoxied up- pics taken, but no time to post, and GF's ISP is hosed up this afternoon- posting from my iPad on LTE. - will take a little work with the sander to get everything flush, but totally doable. Should be able to setup and measure that cabinet next Saturday.

Slow work takes time...

[JonMarsh]

OK, a little photo review here on yesterday's work...


It was mostly about prepping the midrange enclosures and getting one baffle glued up. Here is the start of gluing in the lead sheets, one surface prepped with construction adhesive, and a lead piece cut with cold chisel just before cleaning.




I was using the more expensive "8x stronger" Loctite construction adhesive; it has a rather long working time, which is both good and bad, when you think about it- 24 hours to fully set.




Here, we're a bit further along, with lead sheets glued in and drilled after setting overnight, and installing the heavy felt next.





Here's one of the cabinets, now ready for the front baffle to be epoxied on, using Loctite marine epoxy (my favorite, for applications where you don't want dripping and you may need some gap filling, such as in the slight splinter rip out of the underside of the BB ply in the front baffle).





Last, a view from the man cave where the first cabinet is epoxied and clamped up. A bit of work with the disk sander will be necessary before the epoxy overcoat and veneering, but it looks to be very straight forward- and will be deferred until after loading up drivers for a measurement test next Saturday!

[dar47]

Very productive weekend. :T

Loving the look of the drivers in the baffle, very menacing. :B We going to have to draw something up for your approval to cut the tweet felt, maybe a little paper template with a sharp chisel.

Something I've heard mention before but didn't get, is this Linkwits transformer to bring bass response lower to say for example 20Hrz or just a tweak to get more capability out of a driver that is up to it in a small sealed box?

[JonMarsh]

About the Linkwtiz transform

Here's a good article to explain how the "full blown" Linkwitz Transform works.

http://sound.westhost.com/linkwitz-transform.htm#how-works

It's typically used in the case of putting a very stout, high power handling driver with a lot of Xmax into a small box, and then using Equalization to brow beat the system into the response you want. (OK, I'm exhibiting an editorial slant here, it can be helpful, like putting a Parts Express HO series woofer in a small box and then using an LR transform to get the response you want through extra power...)

Elliot Sound documents and sells an LR EQ module suitable for DIY use in a system. This approach is commonly used for sealed subs anyway, to get the in room response to the needed depth with a manageable size box. You just have to have a beefy motor that will handle some power.

Now, for a well design conventional sealed box system with good Xmax and good power handling, one can also benefit from an LR equalizer, but we don't need nearly as much EQ, don't need any dip EQ to compensate out a Qtc peak, and a modest 4-6 dB will allow increasing the very foundation bass without compromising the system, IMO. Now, in principle, you get some of this anyway with a well designed system and proper boundary positioning. But boys being boys, most seem to prefer a slightly more zaftig bass response profile than pure flat, and it's my experience that with the system alignment I've used in the Isiris and the Wavecor Ardent, which are both critically damped, and -6dB at Fs, that including a passive shelving equalizer in the preamp to amp signal path will give you back that 6 dB and also often bring a smile to your face. :B

Circuit requires a couple of resistors and a cap, double for balanced.

Thing is, it's not an expensive step to take, and as long as your preamp has enough output drive to deliver double the voltage needed to drive your power amp (VERY common and normal situation), then all is well and easy to do...

Interested?

[JonMarsh]

Very productive weekend. :T

Loving the look of the drivers in the baffle, very menacing. :B

Yeah, I'm liking these more and more, though conceptually I expected this... The Avalon Time is like Poppa Bear, the Indra and original Ardent is like baby bear, but these are JUST RIGHT!

[dar47]

It's in a little box of it's own, why not I'll give it a try although I'm generally not a "balls to to walls" kind of bass guy.

[JonMarsh]

It's in a little box of it's own, why not I'll give it a try although I'm generally not a "balls to to walls" kind of bass guy.

Properly done, it shouldn't draw attention to itself- just more fundamental oof and weight on low frequency transients. Just something to consider after everything else is done...

[TEK]

Here, we're a bit further along, with lead sheets glued in and drilled after setting overnight, and installing the heavy felt next.

What is the purpose of the lead?

[benthe8track]

I got one completely veneered and ready for finishing. I'm pretty happy with how the veneering turned out. On the next one I may try to do the facets first then put on the front piece.

[JonMarsh]

Looks sharp, Ben! :T I really like how you were able to handle the book matching on the sides- These will be very interesting looking once finished!