[subsonic1050]

I decided I should probably start a new thread since I'm definitely building these speakers now. Drivers are ordered, no turning back now! I built two test baffles which will house one LM10N driver and 3 each of either the LT2.2 or LT3.2 tweeters. I'm hoping to use these test baffles to determine which tweeter to use and whether I should use a waveguide or not, as well as to determine waveguide shape if appropriate.

[tremrej65]

Good idea the new thread.
The construction looks very well done.
...but did you by mistake made two right side speakers?

[Tyson]

If you decide to go fully active for these speakers, I know that Danny actually has heard and was impressed with HAL's active crossover/DAC modules.  Might give you some more flexibility when it comes to mid-bass solutions.

[subsonic1050]

Good idea the new thread.
The construction looks very well done.
...but did you by mistake made two right side speakers?

Haha, that would be hilarious if I did! But, no, these are two test beds to evaluate which tweeter to use - so they are not the same. You only need one speaker for measurements, so I just built one of each. I'm hoping to also be able to listen to just one and see which tweeter sounds the best.

[Early B.]

Geez, dude -- the test baffles look insane already. Are you a professional woodworker??

[subsonic1050]

If you decide to go fully active for these speakers, I know that Danny actually has heard and was impressed with HAL's active crossover/DAC modules.  Might give you some more flexibility when it comes to mid-bass solutions.

I am really torn regarding how to handle the crossovers. The DSPNexus through Rich was my original plan - and still the direction I'm likely going. In addition to the hardware and software, Rich is such a genuine and helpful person. That kind of customer service is weighed heavily in my mind. I spoke with Al as well, and he was also extremely helpful. My biggest concern is the DAC implementation, and being locked into those DAC's. I only listen to digital, so no worries about double conversions.

Geez, dude -- the test baffles look insane already. Are you a professional woodworker??

Haha, thank you! I don't do it for work - but I've been woodworking for about 25 years and it's quite the "hobby" if you can even call it that. I'd love to do it full time but it just doesn't pay as well as my career. I won't have any problems building the cabinets, but doing all of this testing, crossover design (either active or passive) is all new to me. I've built a lot of speakers, but always from a full set of plans - so this is going to be quite an adventure.

[Tyson]

I'm actually VERY curious to see how this project progresses.  From what I saw (and others have said), the new planar midrange drivers are just as good as (and in some ways even better) than the older ones I have in my Line Forces. 

[mkrawcz]

I am really torn regarding how to handle the crossovers. The DSPNexus through Rich was my original plan - and still the direction I'm likely going. In addition to the hardware and software, Rich is such a genuine and helpful person. That kind of customer service is weighed heavily in my mind. I spoke with Al as well, and he was also extremely helpful. My biggest concern is the DAC implementation, and being locked into those DAC's. I only listen to digital, so no worries about double conversions.

I use the dspNexus 2/8 for my Supermini setup and it’s great. I wouldn’t worry about the DACs. They’re used as the crossover channels. The nice thing is the Nexus is modular for upgrades in the future. You can use the Nexus as a compete all in one crossover/dac/preamp, or use it just as a crossover. it’s intimidating to program using Audioweaver, but over time you will learn and get better at it. Rich is always available to answer questions. The amps you choose to power all the drivers makes a huge difference as well. Which is better, Dansville Signal active DSP or passive? It’s really close and hard to say without going back and forth.  It’s a lot less money to have Danny design and sell a crossover to you than the DSP and all the amp channels needed for the drivers. But the DSP is flexible to tweak and use with any speaker you want to tackle.

[lancruiser_]

IMHO, I would not add a woofer to the baffle with the Radian drivers. When BG Radia offered the FS-880 speaker in ~2014 they used this form factor. It works very well, they are using a custom 8" woofer with a XBL2, double gap, short voice coil magnetic config, Mr. Levitsky knew what he was specifying. A modern ~ 8" equivalent might be something from Purifi, Acoustic Elegance or Dayton Audio. The (4) woofers per box are all powered radiating a cardioid pattern. I am using active crossovers/dsp/room correction, a passive xo might work but I can perform 10 things in a short interval that I could never accomplish with a passive xo, premium passive parts are also quite expensive and have little resale value. Best initial practice would be to use active xo and if you really want a passive, you would always have the working example. I am really impressed with your prior speaker config's and look forward to what you will design. If I can offer any assistance, let me know. The example is one of the "Frankensystems", I have others using BG drivers. I have not used any of the new Radian drivers, if I did I would be using what you have. Mr. Levitsky is a superior designer of planar technology, his Oppo headphones are something to purchase when available. I wish you success with the design and it's implementation. Pictures or it didn't happen, hypers to tech descriptions.

https://www.consonusaudio.com/

https://www.consonusaudio.com/techstory

[sandbagger]

My biggest concern is the DAC implementation, and being locked into those DAC's. I only listen to digital, so no worries about double conversions.

As a dspNexus owner and user, I would not worry about being locked into the dac chips much, Al has updated/upgraded the chips used a few times and is end user upgradable once available. 

[subsonic1050]

I use the dspNexus 2/8 for my Supermini setup and it’s great. I wouldn’t worry about the DACs. They’re used as the crossover channels. The nice thing is the Nexus is modular for upgrades in the future. You can use the Nexus as a compete all in one crossover/dac/preamp, or use it just as a crossover. it’s intimidating to program using Audioweaver, but over time you will learn and get better at it. Rich is always available to answer questions. The amps you choose to power all the drivers makes a huge difference as well. Which is better, Dansville Signal active DSP or passive? It’s really close and hard to say without going back and forth.  It’s a lot less money to have Danny design and sell a crossover to you than the DSP and all the amp channels needed for the drivers. But the DSP is flexible to tweak and use with any speaker you want to tackle.

Yeah, to me there seem to be pros and cons to both. I'd also like to try my hand at passive crossover design. Obviously I don't anticipate being able to do what Danny can do - at least not as easily, and maybe not ever. But I'm hoping that by using various software implementations like Virtuix, I can get a rough idea of what to do. Then keep tweaking and altering things until I (hopefully) land on a good result. There is a lot going on with this design so we shall see - but I'm kind of loving the prospect of learning about all of this. Trial and error can be a powerful tool. If I don't end up with something I'm happy with then I will either drive a speaker down to Danny (this is the huge limiting factor - no way can I ship one of these, and I'm in Indiana) or I will try DSP. I may try the DSPNexus regardless of how any passive crossover I design does or doesn't work - I'm trying to build the best possible speaker here, and I don't want to compromise.

lancruiser - those certainly look amazing! I'm a little curious about the implementation. Don't you get rear wave cancellations going on without any side wings? Also, there seems to be quite a lot of vertical spacing between the drivers - how is it for comb filtering/HF lobing?

As a dspNexus owner and user, I would not worry about being locked into the dac chips much, Al has updated/upgraded the chips used a few times and is end user upgradable once available. 

I'm less concerned with the exact chip that is used than the implementation of that chip. Almost all of the cheap chinese DAC's use the best chips now and measure great - but they certainly don't sound amazing. Have you compared your DSPNexus to other DAC's without using the DSP stuff? I'm genuinely curious about the raw DAC performance.

Also, I have designed and 3D printed some front baffles for waveguide testing. They have replaceable "inserts" so I can swap out multiple different waveguide designs. Still need to print the baffle and inserts for the LT3.2 test baffle. So far the shapes I have are: 1. No waveguide (remove the 3D printed baffle), a 3/4" chamfer, a 3/4" roundover, and a 1" wide by 3/4" deep sweeping curve to follow a more normal horn/waveguide shape. Any other shapes I should try?

[lancruiser_]

 I should have taken more detailed photos, the drivers are as close to each other as possible vertically. The baffle is a solid piece of aluminum cnc'd then anodized. The speakers were a "barn find" so to speak, I was really lucky to obtain them, I understand not many were produced before BG was acquired. I am in the process of rewiring them and possibly adding a "wing" to them, right now they measure well and sound fantastic, no comb filtering or lobing to speak of.  I think your idea of printed baffle waveguides is spot on, I have not the faintest regarding waveguide geometry. You might want to check out The Linkwitz or Keele websites. If asked perhaps Danny would have some ideas on how to proceed. What acoustic measurement technique are / will you be using? I am getting good results with Pocket Clio and a Minidsp Umik-2 microphone / REW software combination.

[CopperFoil]

Also, I have designed and 3D printed some front baffles for waveguide testing. They have replaceable "inserts" so I can swap out multiple different waveguide designs. Still need to print the baffle and inserts for the LT3.2 test baffle. So far the shapes I have are: 1. No waveguide (remove the 3D printed baffle), a 3/4" chamfer, a 3/4" roundover, and a 1" wide by 3/4" deep sweeping curve to follow a more normal horn/waveguide shape. Any other shapes I should try?

Tweeter waveguide profile on the smaller pair of my Line Arrays. 

[subsonic1050]

Lancruiser - those are sweeeeet! Those closer pics help quite a lot. And yes, I see they are packed in as tightly as they can be - I'm not used to seeing them mounted from the rear like that. Those aluminum cabinets are beautiful. Why are you rewiring them? Did they use push-on connectors? 

CopperFoil - That is really interesting - is that your own design? That waveguide profile is the one I currently have loaded up for testing - now I'm just waiting for the drivers to arrive...

[CopperFoil]

CopperFoil - That is really interesting - is that your own design? That waveguide profile is the one I currently have loaded up for testing - now I'm just waiting for the drivers to arrive...

Not my design... Danny Richie designed that Line Array.  And, they are spectacular.  I have second pair of cabinets like that, as well. 

I also have a pair that are 7 1/2 Feet tall... next to be built out.

If your Line Force don't work out for some reason, you should reach out to me - as these are a very special thing.  It's possible a few more pairs of my larger line arrays will be available... and that is something being actively investigated, right now, as the woofers are a proprietary design.

It is quite possible that may very well happen... and it is also a 5-figure $$$ project. But it's End Game stuff, too - like the Line Force.

If others have interest in what I am talking about, feel free to reach out to me privately.  The opportunity may be extremely limited.   

Hopefully the waveguide pics are helpful.  I can probably put an angle finder on it, if that helps - although you may be able to eyeball that, given your experience. 

These speakers are a lot of work... but mine have really been worth it, for sure.

[subsonic1050]

I caught wind of some news which is going to most likely change the direction of this build slightly and solve the midbass problem I've been concerned about. There should be an announcement in Vienna next week which will make these line force speakers an even more compelling proposition. It also means I'll almost certainly be using the 3" tweeter because I'll want to cross even lower than I had previously planned. So I'm at a bit of a standstill at the moment, but it's going to be worth the wait I think.

[subsonic1050]

Also, if anyone has any interest in doing something like this you should order drivers NOW. The prices for Radian drivers are going up dramatically on June 1st. You can still get great prices through US Speaker. On June 1st the prices will be going to what is listed on Radian's site. For the tweeters it's like an 80% price increase.

[subsonic1050]

Well the announcement from Radian didn't come - apparently they are working on a 12" Planar which was supposed to be announced at the Vienna audio show. I got in touch with someone at Radian after the show. He said there are discussions about a 12", but it didn't sound like it was being released any time soon. SO, on with my speakers. I got the drivers mounted in the test baffles and I did a bunch of sweeps with various waveguides. I'm doing this through a MiniDSP to set up a very basic crossover at 1khz. Obviously using a super cheap chip amp here just for convenience in testing. Here is the test setup:




Here is the off axis response for the 3 waveguide variations I tested as well as without a waveguide.

No Waveguide:


Swept Curve Waveguide:


Plain Roundover Waveguide:


Chamfer Waveguide:


To me the the swept curve waveguide and the roundover waveguide look the best, but if anyone has any further input I'd love to hear it.

All of these measurements are also using a PEQ filter at 12khz because there is a hole in the response there. I've tried putting felt on the baffle, moving the microphone, only using one tweeter vs. three - that hole is always present with all waveguides and without any waveguide at all. Is that possibly just the way the driver measures? The factory response shows a bit of a dip there, but not this severe:


It's even easier to see with the smoothing off:


Any suggestions?