[Chops]

Off topic, but digging that Carver gear in your pics. Very cool retro gear. 

Thank you sir! At least with their many upgrades and mods, they don't sound "retro" anymore. 

[Chops]

Okay, so I have a couple of updates on the project... And a question... The question probably directed more towards Danny...

1) I decided on and ordered a pair of Audio Nirvana Super 12 Ferrite fullrange drivers that I will allow to play fullrange. The amp that will be powering these will get a direct feed straight out of the preamp, completely bypassing the dbx Venu 360.

2) One of my friends right here in town is a teacher at one of the high schools, and has complete access to the CNC machine after hours and during the summer. So that means I will be having these cut out on the CNC machine for next to nothing. I'm going to use a combination of both 0.75" MDF and 0.75" BB plywood. In the end, everything including the flat OB panel for the AN Super 12 will be 1.5".


3) Danny, how high of a crossover frequency can I play the Acoustinator N2012 drivers in the H-frames without sacrificing sound quality?

The reason I ask is because even though the AN drivers will be getting a fullrange signal, they're going to be on fairly small baffles, so they won't have much bass support of their own. I'm not even sure how low they can extend on their own without a baffle. I'll have to ask that in the OB forum probably.

Many thanks! I'm excited about this new project.

P.S. - Danny, I still need to by that other pair of N2012 drivers from you!

[Danny Richie]

1) I decided on and ordered a pair of Audio Nirvana Super 12 Ferrite fullrange drivers that I will allow to play fullrange. The amp that will be powering these will get a direct feed straight out of the preamp, completely bypassing the dbx Venu 360.

I have tested and measured that driver on an open baffle. I dropped it into a Super-V test baffle so it was already optimized for a 12" driver in an open baffle and the baffle width plus side wings of that model helped keep the response flat down to a crossover point of just below 200Hz. At least it did with the Super-V driver.

The Audio Nirvana driver isn't a driver you can just drop in an play full range with no filter. And I am not talking about just a high pass filter. It needed an extensive compensation filter to control the rising response, response peaks, and break up modes.

Here was the measured on axis response.



It was real thin down low and would take your head off hot up top.

With an eight part compensation filter I was able to correct the response as seen here. The corrected response is obviously the red line.



Even after damping out the resonance peaks there was still a lot of stored energy and break up in those areas. So a lot of that ringing just doesn't go away.



The other issue with a driver that large in diameter playing full range is that it has really poor off axis response. So the highs are only present directly in front of them. As you move off axis the highs drop out rapidly.

[Danny Richie]

2) One of my friends right here in town is a teacher at one of the high schools, and has complete access to the CNC machine after hours and during the summer. So that means I will be having these cut out on the CNC machine for next to nothing. I'm going to use a combination of both 0.75" MDF and 0.75" BB plywood. In the end, everything including the flat OB panel for the AN Super 12 will be 1.5".

If you are already used to listening to X-Statiks then you are going to find these very different (to be nice). Before I'd put much time or effort into them you might want to do some preliminary test and listening.

3) Danny, how high of a crossover frequency can I play the Acoustinator N2012 drivers in the H-frames without sacrificing sound quality?

The Acoustinators will play up to about 1kHz pretty easily. Ideally though you want to stay just below the mid-range. So 200Hz is usually the upper sweet spot.

[Chops]

I have tested and measured that driver on an open baffle. I dropped it into a Super-V test baffle so it was already optimized for a 12" driver in an open baffle and the baffle width plus side wings of that model helped keep the response flat down to a crossover point of just below 200Hz. At least it did with the Super-V driver.

The Audio Nirvana driver isn't a driver you can just drop in an play full range with no filter. And I am not talking about just a high pass filter. It needed an extensive compensation filter to control the rising response, response peaks, and break up modes.

Here was the measured on axis response.


It was real thin down low and would take your head off hot up top.

With an eight part compensation filter I was able to correct the response as seen here. The corrected response is obviously the red line.


Even after damping out the resonance peaks there was still a lot of stored energy and break up in those areas. So a lot of that ringing just doesn't go away.


The other issue with a driver that large in diameter playing full range is that it has really poor off axis response. So the highs are only present directly in front of them. As you move off axis the highs drop out rapidly.

I know that these drivers are a bit "harsh" right out of the box. I've read where they take upwards of 200+ hours to finally calm down. After that, if they still need help, I might come to you about those compensation filters, or run them through the dbx to tame them. I don't know how many hours you had on the particular drivers you measured. I don't plan on doing any critical listening or review of them until I know they are fully broken in. It shouldn't take more than a couple of weeks since the system is up and running 24/7.

As for poor off axis response, that's really no big deal either. I'm typically the only one listening, and I always sit in the sweet spot. Plus, being in a small room, that beaming will probably help reduce early reflections.

[Chops]

If you are already used to listening to X-Statiks then you are going to find these very different (to be nice). Before I'd put much time or effort into them you might want to do some preliminary test and listening.

The Acoustinators will play up to about 1kHz pretty easily. Ideally though you want to stay just below the mid-range. So 200Hz is usually the upper sweet spot.

The X-Statik's are definitely in a different league from much of anything else. I expect the Audio Nirvana's to sound different, and am prepared for that. I just need to learn to be patient while they break in.

Glad to learn that the Acoustinator drivers will play that high, but yes, I wouldn't get them into the midrange. I just don't want the H-frames to contribute to the sound, but I imagine 200 Hz is still in the safe zone, even for the H-frames.

[Danny Richie]

I know that these drivers are a bit "harsh" right out of the box. I've read where they take upwards of 200+ hours to finally calm down. After that, if they still need help, I might come to you about those compensation filters, or run them through the dbx to tame them. I don't know how many hours you had on the particular drivers you measured. I don't plan on doing any critical listening or review of them until I know they are fully broken in. It shouldn't take more than a couple of weeks since the system is up and running 24/7.

The burn in time won't change the frequency response. It changes the compliance and lessons the stored energy, but all those peaks are still present from day one and on. The same goes for the rising response.

[Chops]

The burn in time won't change the frequency response. It changes the compliance and lessons the stored energy, but all those peaks are still present from day one and on. The same goes for the rising response.

Not saying you're wrong or trying to argue with you, but...

I have heard many speakers totally change in their overall sound from break-in. I had Magnepan's that sounded like the cardboard box they came out of when I first fired them up. After a couple of weeks, they sounded just as clean and natural as any other Maggie out there. They wen't from no bass and thin mid-bass to having nice full mid-bass and somewhat decent bass (considering).

I've had several Fostex and Mark Audio Alpair drivers that sounded cupped and hallow with very etchy treble, to the point of being extremely annoying to listen to. Over some time of break-in, they opened up as well as the treble smoothing out. The Alpair's were on OB's.

Even the subwoofers in my car when a bit on the lean side at first. But after a week of working them in, plus "burning in" in the Florida heat, they filled in nicely.

So in my experience, the amount of compliance and stored energy does effect the frequency response and those peaks to a degree. Now the rising response, probably not so much. However, that can somewhat be tamed by positioning them slightly off-axis. Remember, I'll be able to move these around freely as they will be completely separate from the H-frames.

[Danny Richie]

Not saying you're wrong or trying to argue with you, but...

I have heard many speakers totally change in their overall sound from break-in. I had Magnepan's that sounded like the cardboard box they came out of when I first fired them up. After a couple of weeks, they sounded just as clean and natural as any other Maggie out there. They wen't from no bass and thin mid-bass to having nice full mid-bass and somewhat decent bass (considering).

I've had several Fostex and Mark Audio Alpair drivers that sounded cupped and hallow with very etchy treble, to the point of being extremely annoying to listen to. Over some time of break-in, they opened up as well as the treble smoothing out. The Alpair's were on OB's.

Even the subwoofers in my car when a bit on the lean side at first. But after a week of working them in, plus "burning in" in the Florida heat, they filled in nicely.

So in my experience, the amount of compliance and stored energy does effect the frequency response and those peaks to a degree. Now the rising response, probably not so much. However, that can somewhat be tamed by positioning them slightly off-axis. Remember, I'll be able to move these around freely as they will be completely separate from the H-frames.

The bass can change from the compliance change. And all of those drivers do change in the way they sound after break in, but the measured frequency response doesn't. It's just in the spectral decay (stored energy) where you hear a difference, and that too is from the softer compliance. And I have measured a lot of drivers before and after burn in times. In one set of tests I measured drivers at many intervals during burn in. Above 100Hz or so they won't change.

[Chops]

I see it this way... If I don't like the sound after break-in, I'll play with toe in-out. If that doesn't cut it, I'll run them through the dbx and see what I can achieve there. If that gets me close, maybe we can work on something for that compensation filter you were talking about earlier.

Something tells me I'm going to like the results regardless. But if not, I always have the X-Statik's to fall back on, and can sell the AN's. Only time will tell.

[HT cOz]

Danny

Do you recommend the Apex 150w or 250w plate amp versions?

[Danny Richie]

Danny

Do you recommend the Apex 150w or 250w plate amp versions?

Both of those amps are pretty good amps. For this application I'd go with the higher powered version. And I'd ask Steve about the bass boost modification. 

[Chops]

Well I have the new OB's up and running, on temporary baffles. The final system will be significantly larger. I have to say, treble extension is surprisingly good, and bass output and extension is shockingly good as well. Tight, punchy bass with solid useful output down to 35 Hz. It fades off rather quick after that however. Even male and female vocals sound rather good. There's a little bit of an edge to them, but nothing like I was expecting.

The current arrangement is as follows...

Vertically bi-amped, the Audio Nirvana's are receiving a fullrange signal while the Eminence Acoustinator's are being crossed over at 190 Hz as well as being boosted +11 dB. No EQ or other tone controls are used, nor are the JL subs. They are powered down.

The baffles are 48" tall, 15" wide with a 9" wing on one side. Speaking of the wings, I have them on the outside. I don't know if that makes any difference or not.

Anyway, a few pics...

[Chops]

After further listening and about 30 hours of break-in, the AN's are coming along quite nicely.

And those little N2012 drivers are thumping right along!

[Chops]

I am pleasantly puzzled as to why and/or how these N2012 drivers are producing such strong, deep bass on these small baffles.

I now have them boosted to +13 dB to keep up with the AN's. They are (the N2012's) crossed over at 200 Hz @ 36 dB. No EQ, no tone controls, just straight signal, and these two little 12's are digging deep down into the low 30's effortlessly, with zero signs of stress, and barely any cone movement! And I'm currently hitting musical peaks of 92 dB with just about 5 watts of peak input. The AN's aren't even touching 1 watt yet.

This bass though... It's so musical, detailed, tight, punchy, agile, tactile, extended and just so damn good!

I removed the two JL Audio subs from the room this morning and I can honestly say that I don't miss them one bit! I think I'm going to be in for a real treat once I get all eight of these N2012 drivers up and running. I'll be able to back that gain way down and these drivers will just be idling along the entire time.

[Chops]

Just got in my 4th pair of Eminence Acoustinator N2012 drivers today from Danny.

This is a crude sketch, but this is pretty much what I plan on building. Maybe, hopefully starting on it this weekend. Kind of up in the air as far as the fullrange baffle design. I'll probably make both like Danny suggests and see which performs better.

[Chops]

Danny, several years ago, you sold these bass guitar drivers for I believe the first version of the V-1's. They are now discontinued drivers, but I purchased four of them from you with the plans of building V-1's which never happened. I still have these drivers, still brand new and still sealed up in the shipping packaging.

Now about 7 years or more old, and here they are, still sealed up like I said. LOL

I promise they won't be this time tomorrow!!! 

[Chops]

Delays, delays. If I didn't have bad luck, I wouldn't have any luck at all... 

Go to Lowe's grab the plywood, go to get it cut down, their saw is out of service.

Go to the other end of town to Home Depot. They had nothing but junk plywood.

Go to the next town over to another Lowe's. They have the wood but we would have to dig down about a foot to get to good, undamaged sheets. Before doing that, go make sure the saw works and find a note on it to warn customers that the saw is out of square and is off an 1/8" for every 12"... What the heck?! We asked one of the schmucks there and as usual, they had no clue what they were talking about, so we walked out.

So 3 hours and 50 miles wasted. Well, almost... My brother told us about a nice little restaurant down the street that has really good deep fried chicken gizzards, livers and fish. So we all went there and I treated them to lunch. Plus I let one of my brothers drive my car so I could take some pics and video of it going down the road. 

Anyway, now it will be another two weeks at least until I can attempt to build these again. 

[Chops]

Just for fun since I can't do anything else at the moment except sit and listen to these temp baffles. As I've mentioned before, no EQ or other tone controls. Just simply gain adjustments on the two 12" Eminence Acoustinator woofers. This was taken at the listening position. Not bad at all I'd say...