e-Lips

[Scott F.]

Rich,

Have you thought about trying a conventional active crossover, something like the Pass Labs B-5? Nelson designed this specifically for OBs. It has bass boost and Q controls (though limited) and adjustable crossover points. Not sure what the cost on the B-5 is but I'm thinking around $1200. Jon Ver Halen of Lowther America uses them in a true OB configuration. I've listened to them a couple of times and is was pretty nice sounding. I use the Pass B-5 as a simple XO with no bass boost or Q alteration and it's quite good. Not sure if you are going to RMAF this year but Jon will be running his in his room if you wanted to look at the design.

If you are looking at a three way design, Sony made the TA-4300 back in the 70's which gave you reasonable crossover points plus the ability to boost specific lower frequencies by up to 8db. I used to run one of those and it wasn't a bad sounding unit at all. It's pretty hard to find nowadays though.

Over the years I've listened to most of the DSPs and have always gone back to analog XOs. Dunno, I guess my ears are just sensitive to the digital conversions. Doing OB bass is a different animal though.

[richidoo]

Thanks Scott, good advice. I have heard Jon's demo at RMAF, with B1/F5. It was very lovely playing jazz singers but overall just too relaxed for me. I got the feastrex because it had more bite than the Lowther. I built a B1, it was too laid back. I tried to mod it but couldn't make it come alive. So I guess I wrote off the1stWatt stuff because it is all the same JFet buffer. Maybe that has changed, or maybe the commercial units sound different from his B1 kit. At this point I don't know if the baby feastrex driver can be made to play low distortion on loud classical music, or whether only the expensive Feastrex drivers are capable of that, or if it's just so much smoke. If it can't handle it, then I need to go three way with low distortion drivers, which rules out Pass stuff. But I'll have another look, thanks for letting me know that B5 is finally available.

I have tried every possible speaker type for the Feastrex, and gotten only moderately good results. With all the praise heaped on the Granada I chose to try one last time with that OB recipe. Maybe analog crossover is what it needs, maybe the DSP is messing it up. It does sound a lot better by itself just connected to the amp. But Granada uses DSP speaker management, made by Rane I believe. I wonder if the praise heaped on Granada is just "sounds good" hype playing compressed Diana Krall which sounds good on everything, instead of a critical evaluation with symphonic music, which is always the baby Feastrex' and every full range driver's weak point.

You're right, OB does require a lot of adjustments to make a flat, extended FR. I have heard Orion a few times, and it sounds dead from all the feedback in the 20+ opamps needed to accomplish all the necessary corrections. I have used a lot of DSP plugins in recording and mastering audio, usually they work very well. So all this taken together DSP still seems like the right path for me at this point.

[Scott F.]

I listened to the Granada last year at RMAF and commented that it sounds quite good on classical but I couldn't tell how much correction was going on in the DSP since the distributor wouldn't tell me. I also mentioned the helper tweeter on the back panel that nobody seems to catch. Unfortunately I never got to hear them with any 'progressive' music. They may well have fallen apart.

The B-5 I mentioned is Nelsons crossover for OBs. I've got (or had) the F4 and didn't have enough gain out my pre to get it to work so I went back to my 300Bs.

You mentioned more bite from your Feastex. I wish you were closer so you could hear my PM2As, Altec bass cabinets and analog XO. They sound a fair amount different than the PM5A field coils Jon was running. Ever travel through St Louis? I think you'd find it a pretty interesting listen.

[richidoo]

I think field coils were brand new and not played in the demo the last time I was there in 08. Can't remember for sure. It was the first year of his curved maple baffle.

I know squat about Lowthers. I read some from Jon's site.
http://www.lowther-america.com/
Looks like a very wide variety of drivers for different uses. I would love to hear your system.

I use 300Bs on the feastrex too. It's a nice synergy on the high impedance taps with no feedback. Mine are PP so I have 24W for the driver's lowish 90dB.

The B5 can cross as high as 200Hz. Most people cross my driver at 225-250. It has a resonance at 110 that takes until 300Hz to come back down to earth.
http://www.firstwatt.com/b5.html   

[richidoo]

I found a VST plugin called CrossOver to run in AudioMulch.   
http://www.rs-met.com/

Slope is adjustable in 12dB increments from 12dB to 96dB. Frequency is infinitely adjustable. It can do up to 4 bands and it's free. It is an IIR filter that behaves like a analog filter, summing flat in magnitude, but not linear phase like an FIR filter does (audiolense, acourate, DEQX.) I'll set up the ELips tonite and try it out. Feastrex sound so wonderful in a sealed box, I would love to get a way working with them. Maybe a box sub under the boxes will be the wtg.

The advantage of this plugin is that the whole thing can run inside AudioMulch, which is proving to be very reliable and easy to use. No more adjusting the filter in AudioLense, calculating a new filter, then importing the filter to Mulch before I can hear it. It takes about 3 minites to hear any adjustment. With VST plugins I can tweak parameters in real time. It can host as many plugins as my processor can handle. At the meet, Sol was able to use a Stereo parametric EQ plugin included with AudioMulch to make the Feastrex sound really nice, using only two bands of EQ. I can cascade more EQs so he can have as many bands as he wants. But I will probably try another free plugin from Robin Schmidt called Easy-Q which lets you draw the shape of the response you want, with any number of Parametric filters.

I got outbid on an original version of the Rane RPM26z processor on Ebay auction. I was hoping I would get it for $110, but I got bidbarded at the end, it went for $310. I'm kinda glad because I'm much more excited about the new plugins and staying with a high end DAC. The Rane may have needed mods or repairs as it led a tough life.

But first I need to get the ASIO drivers working again.

[richidoo]

Now that's much better...  Not fine tuned yet, but simple LR4@250 with no EQ at all, and same amps and wires we used at the G2G and it sounds like music. No more kazoo. Sounds like it did at first when I used foobar's simple crossover plugin which was also LR4, no convolution. The convolution seems to be the tough part to get right, for me anyway.  Now I can adjust volumes, EQ etc.

[richidoo]

I spent some time today twiddling the digital crossover settings. I was using Audiomulch host, with CrossOver VST plugin. I tried a lot of different frequencies, slopes and calibrated the volumes of both amps. I couldn't get the crossover region to sound clean. It was always cardboardish and thick. So I listened to the highs alone, then the bass, but muting the channels. I noticed that the bass tone was really screwed up, really flabby and distorted. I removed a bass driver from each side, so it was only one bass one each side, 4ohms, but it didn't change much, just sounded smaller. So either the plugin is shit, or the Audiomulch processing is not high end quality, or both. Booooo!    But hey, at least it worked...

When I was done I switched back to the current amp powering just the Feastrex, full range. Huge, beautiful tone, even a sense of bass. So the processing was screwing up the Feastrex signal too.   I wish I could get it to sound just like this, but with a little bass reinforcement. I'll get there...

Next I will fire up my Behringer  DCX2496 with Didden mods, just to see if I can get a clean integration between the drivers. Although the input/output of the DCX is not great, the processing is known to be good and Jan's output is well designed if a little stuffy from 4562 opamps. But they are in sockets so I could roll in some others.

Sol has suggested I ditch the digital processing altogether and make analog line level filters with opamp buffers. That's what I'll try next, but I don't want to spend any more money on this until I hear if the drivers can play nicely. So far the crossovers I've tried have not allowed me to hear that.

I might be able to roll off the Feastrex with 1st order to protect them from over excursion, then put in 3rd order reversed phase subs with the active buffer. The opamps stuffiness won't be audible at low freq.  Now I'm curious what that Rane processor would have sounded like. They are famous for top notch audio quality.  I'll keep it on the radar.

[richidoo]

I got the DCX2496 hooked up, and it does integrate the two bands well, better than any of the PC based plugins I have tried so far. That's welcome news for the speaker design. A high quality active speaker crossover like Rane or dbx should work well, as is used on the Granada. 

I have scoured the internet for more VST plugin crossovers. I found a half dozen which either sounded lousy in the bass, probably all using the same math, or didn't run at all. I have Sonar, I think it comes with a basket of VSTs, but I'm getting tired of playing that game.

I still have not tried Acourate, another PC based convolution program. It's worth a try even though it's competitor AudioLense seems to have not worked out for me, but many people like it.

So next up is analog line level crossovers to gain simplicity and purity of tone. Woofers need 4th order slope to stay out of feastrex' way, plus baffle step correction, so the filters will need buffering, no passives here. The Feastrexes sound best unfiltered. But that won't match the phase shift of LR4 on the bass, so I'm not sure how that would work. Any advice on that? I'll bring down the HT sub later to try it.  Maybe the Feastrex will sound OK in LR4 highpass if I do it analog instead of digital.  Sol suggested LM833 opamps.

The 300B amps sound delicious in single ended mode direct to the Feastrexes. I made a larger single driver baffle for them before starting this project. Gotta give that a try, but that's a different project.

[tmazz]

I got the DCX2496 hooked up, and it does integrate the two bands well, better than any of the PC based plugins I have tried so far. That's welcome news for the speaker design. A high quality active speaker crossover like Rane or dbx should work well, as is used on the Granada. 

I have scoured the internet for more VST plugin crossovers. I found a half dozen which either sounded lousy in the bass, probably all using the same math, or didn't run at all. I have Sonar, I think it comes with a basket of VSTs, but I'm getting tired of playing that game.

I still have not tried Acourate, another PC based convolution program. It's worth a try even though it's competitor AudioLense seems to have not worked out for me, but many people like it.

So next up is analog line level crossovers to gain simplicity and purity of tone. Woofers need 4th order slope to stay out of feastrex' way, plus baffle step correction, so the filters will need buffering, no passives here. The Feastrexes sound best unfiltered. But that won't match the phase shift of LR4 on the bass, so I'm not sure how that would work. Any advice on that? I'll bring down the HT sub later to try it.  Maybe the Feastrex will sound OK in LR4 highpass if I do it analog instead of digital.  Sol suggested LM833 opamps.

The 300B amps sound delicious in single ended mode direct to the Feastrexes. I made a larger single driver baffle for them before starting this project. Gotta give that a try, but that's a different project.

Oh Rich, this is Nervosa² . You are not even done with this project before you are laying out plans for the next one. 

My kind of guy. 

[Bigfish8]

Oh Rich, this is Nervosa2 . You are not even done with this project before you are laying out plans for the next one.  Shocked

My kind of guy.  Thumbs Up

Rich seems to know his final destination and I admire/envy his abilities to design/build speakers to try to reach the end of his journey!

Ken

[tmazz]

Oh Rich, this is Nervosa2 . You are not even done with this project before you are laying out plans for the next one.  Shocked

My kind of guy.  Thumbs Up

Rich seems to know his final destination and I admire/envy his abilities to design/build speakers to try to reach the end of his journey!

Ken

+1 

[richidoo]

The journey never ends. What fun would that be?  Thanks for the kudos guys.

You don't know the half of it... I spent all night reading about Lenehan Audio ML-1 tiny monitors. I could sell all the crap I own now, melt it down into one simple but high end music making appliance and be done with the tweaking for a while. Maybe take up a different hobby, like pruning perennials, interior painting, 100 other honeydoos, etc.

The other single driver OBs were actually cut and half finished when I decided I needed woofers. Now I think I need these woofers like a hole in my head...  Who said speaker design was gonna be easy? Not on my budget it's not...   But fun it is, as long as I keep it in perspective - it's supposed to be fun. But I am getting tired of my best listening being in my head (on earbuds.) I'm learning a lot about what works and what doesn't, that's the price of DIY. A pro designer already knows what to do. I just found a review tonight about Granada's debut 2009 RMAF having trouble with the woofers overpowering the room, disconnecting half of them and the digital crossover not working on the first day. Now that's funny. 

As much as I am NOT an Usher fan anymore, it was a refreshing treat to hear the Usher Be718 DMD / Moscode / JPS / Equitech synergy at my G2G to remind me of the sound of low distortion accuracy. But the Feastrex have a special something that is hard to describe and hard to bottle for visitors. I have a couple more tricks to pull, but the hat is getting toward empty and I'm looking for paydirt.

[Carlman]

I know the feeling of working hard to accomplish nothing more than understanding what I've learned.  The journey (or in this case, problem-solving) is the thrill.  But when 1 project seems never ending it sure does put a damper on things.  I'm sure everyone here can relate. 

I hope it either sounds good or you get back into listening to good tunes any way you can.

[richidoo]

Thanks Carl!  Carl and I talked on the phone today, bitched out all our problems to each other and felt all better.    Ahhhhh....

So inspired, I ordered the parts for active analog line level crossovers using the well regarded National LM833 opamp, Dale resistors and Dayton 1% .1uF caps. There's 20 caps to make the LR4 hi/lo filters in stereo, so I want to hear it with cheap parts before getting spendy. I also got some of Sol's fav secret giant killer caps. I have a spare Twisted Pear bipolar power supply, so I'll just stuff it all inside my DAC to eliminate new ICs and power transformer. Then I can use the digital volume control to control system volume, and adjust the integrated bass amp separately.

This is the circuit I am using.

http://sound.westhost.com/project09.htm
Crossing frequency is between 100-225Hz using 100nF (0.1uF) caps, and various value resistors 5k-10k.

I downloaded and started reading up on Acourate. It is poorly documented, but there are video tutorials that I think I can follow step by step. Apparently I can make plain jane crossover filters with no EQ or DRC using Acourate. It would be nice to hear convoluted crossovers with no psyche-benders mixed in. See if it's clear and clean. It's still LR4, but linear phase. Then they have the infinite slope filters too, but I don't trust those yet.  The only problem is how to make the 4 filter files joined together into one file that can be loaded into convolver.

[richidoo]

Oh, I forgot to report that I added my nice little music sub that I bought from Brian Bunge on AN into the mix.
http://www.audionervosa.com/index.php?topic=293.0

It's not quite as fast as the OB woofers, but it does flesh out the bottom and give some weight. I put it up on speaker stands which speeded it up a lot compared to sitting on the floor. I'm tweeking the controls to fine tune it. Sounds good, using speaker level inputs from the current source amp.