Author Topic: Trairos  (Read 27245 times)

Offline richidoo

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Trairos
« on: September 19, 2014, 12:42:53 PM »
Construction underway of the 3 way boxes. These are the woofer cabinets/stands. Outer layer is plywood, inner layer is MDF, joined with 1/16" layer of GreenGlue, staples in corners and one staple in the middle of the panel. Even without the front baffle on place, and before the GG is fully cured, the panel resonance is greatly reduced.

Next up the baffles so I can get them playing while I work on the tops.

First time using Tapatalk, does it work? :D

Offline richidoo

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Trairos
« Reply #1 on: September 19, 2014, 12:53:42 PM »
Pics

Internal bracing, acoustic damping (stuffing,) wiring, vibration isolating woofer mount still to come.
« Last Edit: September 19, 2014, 12:57:13 PM by richidoo »

Offline rollo

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Trairos
« Reply #2 on: October 18, 2014, 08:08:14 AM »
Now were talking. Good cabinet size there.


charles
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Offline richidoo

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Trairos
« Reply #3 on: October 18, 2014, 08:15:23 AM »
Aiming for Qtc .5 before bracing and driver volume. Bracing is installed, will post pic before I close it up. Almost done!

Offline Carlman

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Trairos
« Reply #4 on: October 19, 2014, 04:26:59 PM »
Yay!!! Can't wait to hear 'em. :)
I'll have to plan something special when they're ready..
-C
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Offline richidoo

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Trairos
« Reply #5 on: October 24, 2014, 01:14:20 PM »
Some progress made recently... pics:

Photo descriptions

1. Strut bracing connects adjacent walls together, triangulating the corners which are the mechanical "ground" in a box structure. I have found this to work very well, without eating up a lot of volume. These are spaced so that 6 inches is the maximum unbraced span. There are also 3 angled, side to side braces per box. All surfaces are braced. They could have been smaller with 4" spacing, but it would be hard to get the stuffing under them.

2. The braces to the front baffle are installed before the baffle is glued on, with one end coplanar to the coming baffle. While installing the stuffing I elbowed a couple of these off by accident, due to MDF being so weak. But most subs are made of all MDF and a lot more internal stress than these, so it should be strong enough.

3. Woofer box upright as it will stand in use. It can be turned upside down to look better with woofer close to the mid driver, but that risks floor bounce cancellation, so I made it invertable. The speaker wire outlet is a simple hole drilled same size as the hookup wire in the height and width centers of the rear panel.

4. With the mighty Eton 11-580 woofer resting loosely in the hole. These are the same drivers used in the Usher Be-10 and Be-20, which have the best bass I have heard. In early Be-20s the woofer to mid crossover was 640hz! necessary because of the tiny midrange driver, but still, even with 2nd order crossover at 640hz, trumpet reference tracks sounded perfect. Amazing performance in speed and non resonance for a big woofer. they give excellent spatial detail in low freq reverb. Wicked scary slam on transients with strong amps, and they can even do organ music with low Fs of 23Hz although not too loud. I like these woofers. Found a demo pair on closeout recently, never used. :thumb:

5. Closeup of the corner roundovers. The box has a 1.5" radius roundover on the front side edges to reduce diffraction from sharp corner. Actually this speaker will never play high enough for 1.5" radius to come into effect, these would need 12" radius to have an effect.  So it's just for looks, to match the radius that will be on the top boxes for the mid/tweets. The other edges are 1/2" radius made with a router bit.  The 1.5" radius roundovers were made by cutting off extra wood with table saw, making a 45 degree bevel edge, then further paring it down with a couple 22.5 degree cuts on either side. Then rounding off the four 22.5 edges with a 80 grit sanding disk in a drill. Feeling the roundness by hand, it wasn't too hard to make a pretty good smooth roundover. A 1.5" roundover bit is expensive and I don't own a router table, so it's not really safe to run such a big bit by hand.  Moving on...

6. Closeup of the edge of the Eton hexacone material. This is very stiff and light, with mild resonance compared to metal. I don't like the cone cry and 3rd harmonic distortion that paper drivers produce as they flex under high air pressure at high spl. I want to play loud symphonies without the woofer distorting. I also like shallow crossover filters which makes using metal woofers difficult as they breakup too harshly for a shallow simple crossover. This solves both problems. Stiff, light, and relatively mild breakup. Low weight of the cone allows 91dB sensitivity.

7-8. Top and bottom of Eton.

9. The internals of the box, with pink FG stuffing on 3 walls.

The combination of plywood and MDF laminated with green glue, the corner bracing and FG stuffing makes the boxes very quiet. Knock test is very dead. More than adequate for this speaker to play no higher than 500Hz, probably more like 250-300. I think baffle step for the woofer box will be around 300, so I will try to put the passive crossover near there. But I will be doing active through JRiver filters first.

Looking at House of Kolor Urethane candy paints. It's an expensive, complicated process that requires considerable skill so I'm not yet commited to that, but looking for similar alternatives. I did find a Behr wall paint color that I like.  :thumb:   This means, YES, these speakers will actually be painted!

Offline richidoo

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Trairos
« Reply #6 on: October 24, 2014, 02:34:34 PM »
I split the thread for the 3-way project, called "Trairos," after the original 2way Kairos designed by Jeff Bagby.

« Last Edit: October 24, 2014, 02:37:40 PM by richidoo »

Offline richidoo

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Re: Trairos
« Reply #7 on: November 09, 2014, 06:03:02 PM »
This week I worked on getting the speakers working with active crossovers. SUCCESS!  :yay2:

I used JRiver20 as the DSP engine. It has a module called Parametric EQ which allows creating all the necessary filters for a 3 way crossover. JRiver DSP processing is 64 bit so there is no loss of SQ. I also use the volume control in JRiver.

I use my trusty old Presonus Firepod firewire ASIO audio interface. I have used it in the past to make some awesome high resolution recordings, but I've never used the multichannel line outputs before. They sound very good considering the pro-audio grade output stage with lots of electrolytic caps for connection safety. Sol tells me it uses the same wicked excellent opamps he uses in the I60 preamp stage. My opamp phobia is cured.

I am still using the original Kairos 2Way boxes on top while the bigger Trairos tops are being built. Their footprint will match the bass boxes. and Vb is much bigger, to yield Qtc ~.5. The passive crossovers were removed and the drivers wired directly to the amps, one channel for each driver, nothing in between. The amps have direct control over the driver, and this is where the magic comes from.  A cheapo 20uF Xicon electrolytic cap is used to protect the tweeters from the 15w amp.

Sol's I15 amp is on the tweeters, Sol's I60 on the mids, trusty old AudioSource Amp200 (80w) is on the bass. It is getting blown away by the other amps, but I have big bass, so I'm happy enough for now. Not much punch or precision from the budget amp.

After a week of experimenting with crossover settings I finally came up with something halfway decent tonight. I had been trying to do 3 drivers all at once and it was frustrating me. Today I thought it would be cool to just hear the 2way Kairos with active crossover, so I spent a few hours tweaking that to perfection. Then I just crossed in the bass driver at 200hz, 2nd order and adjusted the bass amp volume. Added some baffle step to the woofer. Shazamm. Sounds really good.

Then I started making a punch list of things needafixin. It is pretty long. Short sample:
  • Swap AudioSource amp for more channels of I60 for the bass
  • Upgrade the I15 to latest current mirror design to eliminate the thumps and the protection caps.
  • Add more stuffing to the bass box to lower the resonance to minimum.
  • Measure FR to see how close my ears are.
  • Buy JRiver. I've already extended the trial period, so I have 9 more days of freebie. It is really good. Sound, features, ease of use.

But there's time, and it's more than listenable now. Classical, jazz, pop, rock, bluegrass all sounds good so EQ must be close. Audiophile sound quality parameters are all improved by a large degree. It is very fun to listen to music like this.

But I was almost ready to chuck it just a couple days ago. Computer hiccups, bad crossovers and EQ, soggy bass, ick. It's not a trivial project, I've been working at it for several months from the panning and researching stages. But it's starting to payoff.

The Pentium 4 with XP and 1GB of RAM works fine. If I run other programs with it like Remote Desktop, or if virus or update kicks in unexpectedly it will cause some dropouts or even long pauses. Closing the offending app cures it. But when playing music normally it is only using 4% CPU and 1/2 of the physical RAM to run the DSP. There is a slight fan noise between tracks, but I plan to move the PC into the room behind the listening room and run the DAC cable through the wall to the system.

Pics:

Offline richidoo

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Re: Trairos
« Reply #8 on: November 09, 2014, 06:10:28 PM »
I can use Remote Desktop on my laptop to make EQ adjustments from my listening seat. It's impossible to make progress fine tuning the crossovers and EQ by walking back and forth from sweet spot to computer.

I found a Windows Phone app that does remote control of JRiver. Transport, Volume, etc. called "nMedium" 
http://www.windowsphone.com/en-us/store/app/nmedium-play/b43ec7af-cc82-4dee-af94-9cf44a4dc8d3

Offline mresseguie

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Re: Trairos
« Reply #9 on: November 10, 2014, 12:31:13 AM »
Hi, Rich.

That nice progress you're making. I'll wager they sound pretty amazing now.

I have a couple questions for you specific to this project of yours, and to my (possible) future project. For several months now I have imagined having a setup not too dissimilar to yours. It seems to me like a lot of time and effort must be put in to create a three-way speaker such as this. It is a challenge for you, but one that you are overcoming.

Unfortunately for me, this is entirely too difficult as i am still a beginner. What I hope to do is pair two subwoofers with my Adelphos speakers rather than create a three-way speaker.

So...how would your Trairos sound different from my using subwoofers with my Adelphos?

If I were to dial in the subs, couldn't I achieve nearly the same sound quality?

BTW I finished my Adelphos speakers today. They have been playing now for about seven hours. I know they'll need another few days before they are really broken in, but i am quite pleased with their sound.

Is it just the mid-woofer that is breaking in, or does the tweeter break in as well?

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Offline richidoo

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Re: Trairos
« Reply #10 on: November 10, 2014, 07:27:30 AM »
Congrats! It's an advanced level project. You're not a beginner anymore! The "hardest" part is the box building, routing driver rabbets, etc. The rest of it is adjustments or mental chores, for which you can ask for help. The fun is learning, so we always strive to take on the hardest projects possible. Some things I'm considering for next year are way beyond anything i thought myself capable when I started. Still not sure how I'm gonna pull it off, but it will be fun trying. the only thing that changes over time is the percentage of failures. If you use plans which are popular with other builders, and come with support, then the chance of failure is very low.

As for break in, woofer, tweeter, and crossover parts all need break in time before they stabilize, and the speaker cables too if they are new. Don't worry about break in. You can't speed it up, you can't avoid it, so ignore it. Just enjoy listening to them knowing they will get even better, but it's already good now so that doesn't matter. One day you will suddenly notice how open and smooth they sound and how low they play, then you know it's done. Don't create anxiety for yourself by counting days and hours, because that will dilute your listening enjoyment. Just forget about it. Focus on the music. The speakers are just an instrument to connect you to the music. The music experience is always the goal. Put on some music you really love and your attention will be drawn away from the sound and back to the music.

You can set up your subs with similar crossover freq and slope as my active speakers, (12dB/oct@150-200Hz) and that is a good place to start. But you can experiment with steeper slope to match your mains, and different frequencies from 50-250. Expect to spend some time for fine tuning process. I think the Rythmik amplifier has a high pass line out to the main speakers' amp? That should make it pretty easy to tweak.

Active amplification increases damping (control) of the drivers dramatically, so the clarity and punch increase accordingly.

Yours won't sound exactly the same as mine since you have passive crossover with steeper slope on the Adelphos. Kairos' slanted baffle allows a shallower slope crossover. Your subs are active, with servo feedback, so that should sound better than my bass setup with the soggy amplifier. I'm sure you will be very happy with the result!

Offline richidoo

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Re: Trairos
« Reply #11 on: November 16, 2014, 02:04:04 PM »
Oops, forgot to reverse polarities on my LR12 crossovers. :duh That explains why I couldn't get the mid and bass crossovers to gel.

I'm already tired of dealing with the computer for music listening. Sonos' ease of use has spoiled me rotten. PC makes changes very easy and fast from the listening seat, so it's good for designing crossovers but for general use it repels me from listening in general. ALso, JRiver can't input an analog signal without clooging around and upgrading my PC/OS. Minimum phase filters are good enough for me if they are active line level, so I have no real requirement for DSP. Everything can be done in analog and should be easier to use, cheaper  to acquire and better SQ than my current PC/audio interface setup. I would need DSP to do linear phase crossovers, but no budget for that now, and it's even more computer complications.

I'll use LR12 crossovers based on Rod Elliot's P81. I did LR24 active analog crossovers before, sounded great, even with lesser PS and opamps than I would use now. It should sound better than the firepod without the electrolytic output caps and SE/BAL conversion. I can incorporate analog line level baffle step correction with the crossovers, and will build it as a preamp with input select and remote volume controls. It'll take a while, but it makes sense. I'll buy JRiver and use it in the meantime. Missing my TT and FM will spur me on to complete it quickly.

I have PCBs, output transistors, huge 1000VA power transformers, and big heat sinks on-hand now to build 2 high power version monoblocks of Elliot P101 MOSFET amplifiers for the woofers.

4 or 6 mono channels of Sol's 60 watt amplifier will require making PCBs. It would be great to make that amp available to the world, so we have PCBs on the to-do list. This project will be the impetus for progress on that front.

Offline jimbones

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Re: Trairos
« Reply #12 on: November 16, 2014, 04:30:44 PM »
Very nice. And i notice you are using the Satori sb29 tweeter. I am using the regular SB29 and it is very good, that can only be better.
I have to check out the Eton drivers. How do they compare with ScanSpeak?
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Offline richidoo

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Re: Trairos
« Reply #13 on: November 16, 2014, 05:36:32 PM »
The SB29 is a great tweeter, and for the price it is amazing. JansZen Loudspeakers uses it rear firing for their great speaker. The dimple dome really reduces distortion a lot by fixing the center of the silk dome to a fixed post in the center, so only the donut around the post moves. Normal domes have a lot of slop at the center. Scanspeak puts a felt pad close behind the revelator air circ silk dome to physically dampen the vibrations at the dome center. I don't know how the Satori improves on it in SQ, but there are a lot of upgrade features.

As for woofers Scan makes some different lines for different budgets. I have heard the aluminum 7" Illuminator, it is wicked awesome paired with Raal 140mm ribbon and TACT linear phase crossover in Selah Audio Mejor. Hearing flugelhorn playing through it made me feel like I was playing it myself, hearing all that spitty lippy brassy detail up close to the horn. But I don't know what their large woofers sound like, they are not often used in the DIY world due to the high price. The Etons are very expensive too, but I got these on closeout when a custom builder sold off the parts because the buyer never came to pick them up. :)

I had these same Etons (11-508) in my Usher Be20s way back. I loved the bass they made in ported box, so I went for these again. Their sensitivity should work well in a passive crossover with the SB mids, allowing extra sensitivity for baffle step correction without having to attenuate the mid much. They have very low Fs, low mass, honeycomb constrained layer cone construction, and low inductance, so they can play cleanly very high. The ushers crossed them at 640Hz with 2nd order! I listened to my mono trumpet midrange reference recordings and couldn't hear the crossover to the little 4" midrange at all.

I crossing them at 150Hz now, but once I get things sorted I might take it up higher for bigger scale, more ballsy sound like the Ushers had. I'm hearing a little bass resonance, the boxes need more stuffing. Hardly any in there now and very small resonance. That's why I made such big boxes with Qtc .5, so there would be excellent natural damping from the box. We're listening to solo piano which is torture test for bass accuracy.

Fixing the polarity tonite really made everything come together. Just flipped the midrange SCs. I prefer woofer and tweeter positive and midrange neg.  I can do it in JRiver DSP also (room correction module)  but that's just another bite out of the CPU apple.

Earlier tonight after I switched the polarity and pulled out 1dB of baffle step on the woofer my wife said from the other room, "wow those sound really good now."  Then just now sitting next to me on the music couch she said again "these really sound good," with a look of amazement on her face like congratulations you finally made good speakers! Atta boy! Now take out the trash.

Last night I was grumbling about how bad they sound. Sitting in the sweet spot there was too much muddy bass, while in the kitchen 15 feet further back there was no bass at all.  

The settings are still fine tuned for the wrong mid polarity, so I'll have another aural session with Aimee Mann again tomorrow when all the haters are gone. Her voice is perfect for voicing speakers. Besides I like to look at the CD cover.
« Last Edit: November 26, 2014, 02:21:35 PM by richidoo »

Offline richidoo

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Re: Trairos
« Reply #14 on: November 26, 2014, 02:38:39 PM »
Speakers are all tuned up. The EQ is adjusted after correcting the midrange polarity. Nothing changed except the baffle step correction. Instead of separate baffle step corrections for mid and woofer, I put them together into one filter, and placed it before the crossover filters as it would be in an analog filter. Sounding very good.

I'd like to tighten up the bass further. Some of that is the amp, but I will add some more bass stuffing to lower the resonance to the minimum, that should tighten up the bass some more too.

I still have the cheap Xicon 20uF electro caps on the speaker wires as protection for the tweeters because the amp I'm using has a turnon thump.  But the cap adds phase error to the crossover,  so I need to get it out of there. The amp has a revision coming which will cure the thump. The Xicon also does the typical nasty gravelly, screechy electrolytic things to the treble so I'll be glad to remove it.

The good news of the day is that TedB on AC gave me a clue about inputting analog sources into JRiver. So I poked around a bit and found the setting to input ASIO audio directly into JRiver. So now I have vynil and radeo playing. And it is pretty easy to switch sources.

I'm continuing to design the all-analog crossover on a protoboard, but with the analog sources working well in JRiver, I may stick with JR for a while. I paid for it today, so might as well get to know it. There are so many features it will take a while to use it all. Sounds good!