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Adding a tweeter to MMG

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Posted on February 18, 2017 at 10:11:51
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
As I had posted in a different thread, I am considering using Magnepan MMGs as a midwoofer to an Open Baffle speaker system I am putting together.

I was discouraged from doing that as the tweeter section of the MMG is not particularly good.

I don't give up easily, and I was thinking what if I built an add-on to the MMG of a 4 unit array of something similar to the BG NEO-8s?

That would be about 32" of tweeter per side.

Some things I don't know that might help;

1) If you take apart an MMG, what does the tweeter look like?
2) Are there pictures of the MMG naked? (speaker porn)
3) If the tweeter array can't be directly integrated into the existing structure, perhaps a wing (& a prayer) with the tweeters mounted in that?
4) The MMG main speaker would handle frequencies from 80hz to Xhz. The NEO 8 clones supposedly can crossover as low as 350hz, but I was thinking 1khz. Any suggestions?

What are y'alls thoughts?

 

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RE: Adding a tweeter to MMG, posted on February 18, 2017 at 14:21:34
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
I got a call from the local (about 35 miles away) Magnepan dealer, telling me that they received a pair of MMGs in. So I toddled on over to listen.

The fellow was quite friendly, and took his time and we listened to them attached to a streaming music player and a name brand 2 channel amp. The room had high ceilings maybe 15' square with lots of wall treatments in the corners and on the walls. It didn't look like an acoustically well designed room. I guess that's why there were so many treatments.

At any rate he began by playing some solo piano, which sounded good, reasonable sound stage, seemed pretty natural. He played an orchestral piece which also sounded pretty good. Most everything acoustic sounded quite pleasant at various volumes.

However I wanted to hear something with more drums and cymbals stuff that would show off the control, etc. So I asked him to find some Jeff Beck, hoping for something like Live at Ronnie's. The Beck he found was something in the heavy metal genre which neither of us cared for. He switched to some Eric Clapton, and the whole percussion section sounded like crap. OK, it sounded like it was playing from a 4" transistor radio speaker somewhere behind the Maggies.

He was getting a little frustrated, so he switched to a pair of .7s and these sounded better but the bass sounded bloomy, like there wasn't enough control.

At any rate I was disappointed. But I wonder whether it was the room or the speakers.

 

RE: Adding a tweeter to MMG, posted on February 18, 2017 at 15:58:36
Satie
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Posts: 4346
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What you are describing sounds like an underpowered amp was driving the MMGs and it did not have the headroom to drive percussion.

As to your idea of adding a tweeter to the MMG, it is probably more of a near supertweeter you want to add. So a true ribbon tweeter would be the better choice. You can add it on a "wing" and make the combo into a 3 way speaker using the MMG tweeter up to around 5khz. Example of what you would want is in the URL.

The Neo8 is a mid and the PDR version is a mid tweeter, The Neo3PDR is the tweeter of choice in the BG Neo line. A good true ribbon will do better on detail but will have more distortion. The tweeter I suggested is single ended, not dipole. This is another more robust and flexible option at a higher price http://www.parts-express.com/aurum-cantus-g1-ribbon-tweeter--276-420

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 07:49:30
ahendler
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Most Maggies at dealers are demoed in heavily damped rooms designed for dynamic speakers. These rooms kill the sound of Maggies, especially the bass. I once told my Maggie dealer that I didn't know how he ever sold any Maggies because they sounded so awful in his store. He admitted that Maggie sales were awful. They never learn
Alan

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 11:20:46
JBen
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If that was our dealer in Boca, I'd be surprised that they called you to audition the MMG. Most likely, they would have been hoping to steer you up to a higher model. This attempt would be fine, if an honest portrayal of the MMG is first made.

The problem is that a NEW set of Maggies, all models but more so MMG's, will sound awful no matter what amp. As they approach the 200th hour of playback mark, the full break-in comes into effect, revealing a fuller range of beauty.

Again, if Boca, their largest room is better for Maggies, when on the wall to the east, unless they've changed something lately. Not that MMG's or even 1.7's would get there easily. Perhaps if you needed to audition it with a monster amp, LOL.

Dealers do face challenges in trying to be fair to speakers like these. It's so much easy to bundle up a few $000's in a dynamic demon's wrap.


 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 15:50:40
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
It was the guy in Deerfield beach, right off of Hillsborough. He didn't try to upsell me too hard, though he did play a pair of .7s, and showed me the whole family.

I was pretty upfront with my plan, and budget.

It was one of the smaller rooms to the left (north) coming in the front door. The bass on the .7s is one thing that disturbed me, in that it didn't seem under control at all. Regarding the bass on .7s, I just think that room has a nasty node, or something.

I sent the guy the following, do you think it is reasonable?

==========================================================
Thanks for taking the time to let me listen to the Magnepan speakers today.


As you were able to tell I was not impressed.


I was trying to determine whether it was the room, the amplifier, the music, or me. Many people say many great things about the speakers and I can't believe that what I was hearing was the same thing that others rave about.


A few things about the setup;

The room appeared to be about 15' square with 12' ceilings. There were treatments in all of the corners as well as the some on the walls them self. Am I correct regarding the dimensions?

The amplifier, which I do not remember the name of (Classe?) appeared to be relatively low power, 150 watts per channel. If not please indicate the amplifier model or specs.



I guess the best choice is to put a pair in my listening room, and see what I hear. The MMGs do have a 60 day home trial, which I hesitate to take advantage of since I am so ambivalent after listening to them. Is the 60 day trial;

Available through your store?

Something that you have any hesitation in doing?

Is there a restocking fee?
===================================================================

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 16:30:19
josh358
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I know the MMG's and larger Maggies but haven't heard the .7's. I think you're probably right that the room was to blame, if you read the reviews of the .7's I haven't seen any complaints about boomy bass.

I think BTW that the .7's would be a better choice for you. I've owned and love the little MMG's and they're an amazing bargain but they're Magnepan's budget speaker and it really doesn't make sense to mate them with the GR dipoles.

Also, regarding your original query, again, I think you'd be better off with the .7's than adding a tweeter to the MMG's. There's a lot more to good sound than just throwing good components together with a seat-of-the pants crossover.

In any case I wouldn't use the Neo 8's as tweeters with the MMG's, as Satie says, you'd want the Neo 3's. But since you're talking to Danny about building a line source and you're talking Neo 8's, why not make a full-length line of Neo 8's and Neo 3's? Or maybe Neo 10's and Neo 3's. Now we're talking about a truly impressive system.

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 17:53:46
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
Josh, I agree with you that there is more than just throwing some drivers together...

However,

1) I enjoy building and tinkering as much if not more than listening to music. So I may be a little unique in that sense.

2) Someone has to throw drivers together in unlikely combinations, if for no other reason than they are there.

I know my methods aren't scientific, but there are plenty of guys that are a lot smarter than me that are crunching the numbers, picking the perfect drivers, designing the perfect crossovers and enclosures. I try not to do things that are too stupid, look for bargains where I can and think outside the box. Some people might say in a different reality, not outside the box, but I have fun and don't hurt anyone...

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 18:11:34
josh358
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February 3, 2012
Sure, and I'm all for that! We're inveterate tinkerers here and we've done some pretty, well, interesting stuff, from listening to our speakers sideways to creating Frankenpans and I've enjoyed your discussion with Danny. Hell, the guys at Magnepan are tinkerers too, as are a lot of people in audio -- some things can be done by the book but when it comes to something like speaker design, there's still as much art as science. So I hope you'll take our suggestions in the spirit they're intended -- we're always looking for ways to make things better with whatever glue and string happens to come our way.

 

RE: Adding a tweeter to MMG, posted on February 19, 2017 at 23:44:45
JBen
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That's the place. I usually approach it from the Boca side and the dealer is just a few hundred feet away from their shared county line.

The email request is very fine. I'd be curious about what kind of reply you get.

I do wonder if it is advisable to let the email be seen here. Magnepan checks the forum and the dealers become naturally defensive if called on something. Given the good attention that you were given, I would have waited for a reply. Then again, I've known them for years and not even bought a thing from them...yet they are patient with my requests.

In fact, perhaps it is time for me to finally go listen to the .7.

 

RE: Adding a tweeter to MMG, posted on February 20, 2017 at 05:09:59
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
I agree they were very friendly, they did not try to pressure me in any way. They took time with me to listen to various types of music. I have absolutely no complaints about the store or the people there. If I had a problem, I would never have sent the email, nor would I even consider bringing a pair of Maggies into my home.

I have been to another store in Hollywood (which shall remain nameless) where I was made to feel like a Baal worshiping heretic because I enjoy multi-channel music. When I went to the Hollywood store years ago to listen to the Emminent Technology LFT-8Bs I never got to hear them and because I needed to be converted to two channel analog nirvana.

 

RE: Adding a tweeter to MMG, posted on February 20, 2017 at 08:43:14
RickeyM
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Posts: 2134
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I agree here with Satie on the super tweeter. The Maggie QR tweeter in it's range is a very good tweeter. Here's where I'm coming from. My first Maggies were MMG's which I Gunned. The midrange detail and clarity was fantastic. Not overbearing or louder, just more realistic. The midrange even bested a pair of stock MG-2.5R's that I auditioned. Had I not heard the Maggie true ribbon, I probably would have gone the super tweeter route.

 

RE: Adding a tweeter to MMG, posted on February 20, 2017 at 10:17:38
aceinc
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Posts: 25
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Peter, Did you Gun these yourself, or have PG Gun them? If you did it yourself, is there a build thread?

 

RE: Adding a tweeter to MMG, posted on February 20, 2017 at 10:40:39
Satie
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Cool, how did you implement your supertweeter ribbon? How is it mounted and how is it crossed over? Do you low pass the MMG?

 

RE: Adding a tweeter to MMG, posted on February 20, 2017 at 22:41:50
JBen
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Ha ha! Aceinc, V'been there, done that. Xcpt...the demo happened because I did not touch on my preferences, which are stereo & analog...but also SS...and the guy had an obvious preference for tubes. One does not mess with THAT, either.

Now, did you not have a sensation like entering the magic wands store in Harry Potter? Except with old audio hardware instead of wands? I could almost picture it in my mind:
"Ollivanders, Sellers of Fine Audio since 382 B.C."

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 07:30:53
aceinc
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Posts: 25
Location: Florida
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JBen, actually the longer story which I have recounted elsewhere is about 8-9 years ago I called up, specifically asked if they could demo the LFT8b, setup an appointment, arrived at the proscribed time. When I get there the proprietor ushers me into the listening room and there against the back wall are the LFT8bs with dust on them. laid out in from are a pair of point source 40" towers attached by by firehose sized cables to massive tube mono blocks which is in turn attached to a minimalistic tube preamp attached to a turntable with an 8" high translucent platter.

He gushed about the auditory epiphany I was about to experience, and put on a Jackson Browne album. Unfortunately I am a philistine I guess, because I didn't get it. It sounded nice, but no better than my KEF 105.4s attached to my Emotiva XPA1 monoblocks. Also I wasn't fond of the extremely low level hiss and pops (barely audible) I heard, that digital media does not have. When I mentioned these things it was as though I had threatened his first born with a hatchet while kicking his dog. He started spewing about how digital encoding slices and dices the music and gets rid of inaudible things that make the music real.

Then I mentioned that I actually enjoy multi channel music, SACD and DVD Audio. Well if he had a rail, bucket of tar and some feathers, I would have been in big trouble. I think he actually started to twitch.

Now I was just wasting his time. I never did get to listen to the LFT8bs.

I went back recently because they had a pair of B&W 803 Matrixes for sale at a fair price, and I had a pair of B&W 805 Matrixes I wanted to sell. When I came in I brought a Sheffield Drum CD which I use to test speakers with. The owner had delegated the task of working with me to his son. He was impressed that I chose Sheffield Drum for testing at the same time disdainful of the fact it was a CD. The 803s sounded great. I was ready to trade. He hooked up my 805s and of course decided to play an album. The woofers on the 805s started pulsing at about 10hz. He had no rumble filter in the circuit. They sounded just as good as the 803s, with less bass. He poked and prodded, and listened intently and declared them satisfactory.

Now I know he's a dealer and needs to make a profit. The 805s sell in good shape for between $600 - $800. I figured if he were to offer me $400 he'd make at least a 33% margin, I'd take it and buy his speakers. He offered $200, non-negotiable. Two weeks later I sold them on Cragislist for $600 and found a pair of 802 Matrix S3s for the same price he was selling the 803s for.

All's well that ends well I guess.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 08:49:20
RickeyM
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Posts: 2134
Location: East Coast
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I think the last part may be a bit confusing. After hearing the MG-2.5R, I bought them. No further mods were done to the MMG's after Gunning them. I figured that modding the crossovers on the 2.5R's, Razoring the panels and adding hardwood frames would raise their performance far enough above the Gunned MMG's to make it worthwhile.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 08:55:50
RickeyM
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Posts: 2134
Location: East Coast
Joined: March 15, 2003
I did the work myself but sorry, there is no build thread. With info gleaned from the threads at the time and PG's x-o diagram. I differed a bit on panel construction and crossover components so I referred to them as "Quasi-Gunned".

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 16:08:39
Satie
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Posts: 4346
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Considering what you were playing with, B&W 802 S3 and the medium sized KEF, what are you looking for from an MMG? Are you looking to get a good detail and soundstage performer by bookending the MMG with a GR sub and the ribbons? Essentially using the MMG as a mid/woofer section?

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 16:10:17
Satie
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I see, so did you complete the project?

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 17:02:26
RickeyM
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Posts: 2134
Location: East Coast
Joined: March 15, 2003
I've Razored the panels, using modified external X-O's, and built braced stands. The hardwood frames will get done this Spring after I replace the tweeters. I blew on of the ribbons (my own dumbness) and because of the age of the speakers, both ribbons will get replace.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 18:35:03
russ69
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Posts: 916
Joined: December 13, 2009
I've been following your threads. It seems like you are working at putting together a very good loudspeaker using an affordable Magnepan as the basis for the system. I don't want to put you off but all Magnepans will have you spending serious money on the associated electronics. It all starts pretty innocently then as you try to get more and more out of the system, the spending starts.
I think I am going to recommend you just get a pair of 1.7s (the best deal in Magnepans) and do your best to optimize that system. Placement and power being the biggest challenges. The true ribbon Magnepan tweeter is very good but the 1.7 is a decent system with the right setup. The 1.7 is a good starting point into the world of Magnepan.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 18:57:45
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
My purpose as you have intimated is to come up with an inexpensive mid/tweeter section for the GR-Research Open Baffle Subs, which I call a woofer section.

I am building the woofer section now, and am playing around conceptually with a dipole/open baffle mid tweeter section. One concept is the MMG, another is an open baffle line array, another is an open baffle MTM.

I may have line on an old pair of SMGs for cheap, I have ordered a pair of BG Neo 8 clones for playing around and I have a some other drivers from another project I never built. But unfortunately I am out of town on business until Friday, so I won't be building/buying anything until the weekend.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 19:00:45
aceinc
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Regarding electronics, I will be driving whatever I get with a pair of Emotiva XPA1 Gen 1 mono blocks. So I should be able to handle whatever I come up with. I have the Emotiva XMC-1 upstream from that.

 

RE: Adding a tweeter to MMG, posted on February 21, 2017 at 21:23:08
JBen
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Aceinc, I am happy that you got the B&W's you wanted...and no tar and feathers treatment, LOL. I've always found the company's speakers to be worth every penny, if one wants good boxes. If I had to have boxes, I would go for them. In fact, it is what I ask friends to look into when they ask. Which is also how I get to enjoy the B&W's often (when I visit them :).

If you get a planar system put together, it will have a different character, as you already know. That said, good B&W setups can throw a VERY wide sound stage. They are less adept at making it deep or provide 3D imaging, but the right power amps can help. Now, most of their speakers deliver some very realistic instrumental and voice textures rather easily, almost regardless of placement. Many planars may do as good, and often even better on this count...but their surroundings will need attention first.

Anyway, I'll be at the local dealer's place on Saturday. I've scheduled demo time mainly with the 3.7i. This time they will be in a smaller room, which may satisfy my curiosity about something.

I also asked for some time with the .7 model, though no special setup will be made. If you let me know a few of the music pieces you tried them with, I'll see if I find them here. Then, I'll take the .7 & 3.7i to task with them. I have no idea where my copy of the Sheffield Drum/Track test CD went. I am sure I'll find it...likely borrowed by someone.

 

RE: Adding a tweeter to MMG, posted on February 22, 2017 at 13:16:54
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
JBen, I did receive an email from David. He suggested we try a bigger room and invited me back. He also said they do not offer the 60 day trial.

As far as music, the stuff that sounded poorly was Eric Clapton. See if he can play some blues ala BB King, Clapton, the Winter brothers, Rick Derringer, something with a good down beat and slow bass riff. I really liked listening to Jeff Beck Live at Ronnies recently on my B&Ws.

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 00:55:39
JBen
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Aceinc, I found "B. B. King & Eric Clapton - Riding With the King". No issues on my [heavily modded] MMG's playing "solo". I spent the most time listening and measuring songs #5 & #12.

The bass on #5 (Three O'Clock Blues) even rattled something HERE in this room. I am writing from a room 30ft away straight line, on a PC remotely operating the others. For this to happen, however, I had taken the low filter off (which normally limits the "too much bass" of my MMG's.)

I also ran them with the cone woofers on briefly, for comparison. The additional low reach of the woofers can be heard and can be easily measured. However, their absence is not missed. One still gets enough of the bass, and often some fairly good dynamic punch. (though, sure, unaided Maggies can't do that....yeah, right.)

During the upcoming demo, my guess is that it could be the .7's the ones that get closer to this, if I remember well what you described. The current MMG's, out of the box...no chance. Since I won't be able to measure there, I'll just have to train my ears to one particular song.

So, please let me know if you have a preference for any of these songs in the album and I'll include it in the CD's that I am preparing for the demo session.

Here are SPL peaks reached for the respective frequencies during the initial 1 min 30 secs of 1 piece, with/without woofer. This was on Wednesday evening, mindful of my neighbor. (Please note, "no filters" means that the mid/bass driver is in its "natural" range, without extra xover filtering. This is NOT the normal usage. Normally, I use a low filter as in the last 2 graphs. One is another song (played for 2.5 minutes) but "with filter on". The other, #4, is the normal frequency response sweep, also with the filter on).

1. (below) BBKing-Clapton 3Oclock Blues 1.5 minutes -Peaks at -9db direct M-PC no Filters no Woofer.png






2. (below) BBKing-Clapton 3Oclock Blues 1.5 minutes -Peaks at -9db direct M-PC no Filters + Woofer.png




3. (below) BBKing-Clapton Come Rain 2.5 minutes -Peaks at -9db direct M-PC no Woofer.png




4. (below) MMG's frequency response measure at listening position on Feb-15-2017 (current but expected to change after upcoming room reconfiguration)



 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 08:26:46
Satie
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Posts: 4346
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SMGs are too short to be a real line source, I suggest you drop that option.

The Neo8 clones from China have a serious primary resonance issue in the midrange around 300 hz which is rather minor with the original BG drivers. The second issue is that you need a multiplicity of Neo8 drivers to cancel out the very prominent 12khz cavity resonance - about 6 per side. But if these clones are well made they will give you an idea of the clarity you can get with this kind of driver.

Your idea for the MMG is solid but a 1.6 + a later addition of a ribbon tweeter will do much better. The 1.7 is already a 3 way and has a pretty good tweeter so it would be a waste to pay the premium for that when you intend to apply a ribbon.

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 14:22:15
aceinc
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JBen, I am in Atlanta on business. However I get back tomorrow evening, and I have the physical CD you are referring to, and will check out the cuts you reference.

What software are you using to get the graphs that you are displaying?

BTW, I live off I75 & Griffin in Broward if you ever get down to my neck of the woods and want to check out my system.

Paul

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 14:41:35
aceinc
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I intend to xover the Neo 8 at a minimum of 1khz so 300 hz will be out the bandpass. I was wondering if the 12khz hump;

a) existed in the clone.
b) could be resolved with the notch filter outlined for the original Neo 8.

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 17:18:56
JBen
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Aceinc, I'll stay tuned for when you return.

The graphs are from REW (Room EQ Wizard). I've been using it since 2008 to help me shape my Maggies up more objectively. It is a free program that allows measuring a whole lot of useful things. We can talk more about this later but it is invaluable for things like what you have in mind.

Not far, I am in Coral Springs so yes, when the time comes I'd love to.

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 18:08:44
aceinc
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I have been using REW for a number of years as well. I have never used it to do this type of analysis, however.

I used it to set up my subs, mainly.

 

RE: Adding a tweeter to MMG, posted on February 23, 2017 at 18:49:01
JBen
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LOL, that does not surprise me, but at least it makes you familiar enough to explore further. When REW started, it was sheltered in the Home Theater Shack. With folks having headaches adopting subwoofers "properly", REW was a natural resource. Its default settings even came oriented towards this purpose. Along time, it has evolved into a much more ample tool set. Just make sure that you have a recent version. I use the "multiple REW instances" version for Windows.

Then, for the reasonable price of a good cup of espresso, of course :) I'll be glad to give you the expanded tour. For now, notice the little camera icon at the upper left corner of some plots? It creates snapshots. Also, you can tell REW to scan at full frequency vs the original default low range.

 

RE: Adding a tweeter to MMG, posted on February 24, 2017 at 00:37:32
Satie
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Posts: 4346
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Yes, the 12khz cavity resonance is present in the clones, appears to be worse than in the original, at least initially, later measurements posted at madisound did not appear as bad as the earlier clones.

You can fit a notch filter just as you would for a single Neo8. Personally, I quickly moved to a line array once I heard the individual drivers since I did not want the phase shift from the filter and was aiming for a line array and for a crossover below the midrange, which I knew cancels the resonance at the far field. I did not want to lose the imaging in the vertical dimension that the line source provides.
I ran them to 300hz initially, and used them up to where their dispersion falls off at 5khz. Then I started running them further up and finally stopped low passing them in favor of letting them run and adding in the ribbon as a supertweeter as Apogee and Eminent Tech did.

 

RE: Adding a tweeter to MMG, posted on February 24, 2017 at 20:28:08
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
Three O'Clock Blues is good. I got home from Atlanta late, and there is a bit of drama I need to deal with, so I can't focus on the music much.

Paul

 

RE: Adding a tweeter to MMG, posted on February 25, 2017 at 02:56:37
JBen
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Got it. Good luck.

 

RE: Adding a tweeter to MMG, posted on February 25, 2017 at 15:54:24
aceinc
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Basically, I had to change my flight to a later flight to be able to finish my work and just before I boarded, my wife told me that my mother in law that lives in an attached apartment was transported to the local emergency room.

So I was unable to focus on the CD, although I did squeeze in a listen to 3 o'clock blues. It sounded nice on my existing 802s.

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 08:35:17
JBen
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Aceinc, I hope that she is doing well by now. I am in a bit of hurry to leave now -- related to my best friend's mother passing away -- but I'll probably PM you later today.

I did not get to listen to Maggies other than the 3.7i, which ate up all my time...and should not have. Had to wait for a blasted power amp to fully warm up!

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 11:12:23
aceinc
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What type of power amp requiers more than a minute or two to warm up?

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 12:09:41
JBen
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Sent the PM.

You'd be surprised. For example, all my Paround HCA amps and also the nearest friend's Halo A21 are so well known to me that I can tell. They sound great a few minutes after warmup. However, they deliver their most delightful personalities only after vigorously driving for over an hour. I've often walked into my friend's room, where B&W's are being driven, and know right away if he had been playing for long. LOL, like my Maggies, the B&W's are not shy about denouncing things like these.

Which brings me to what I heard. A 75wpc premium tuber driving the 3.7i's with decent aplomb at first but not delivering the real goods until close to an hour later. I know the 3.7i enough; they were yelling "this is unfair!"

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 18:12:56
aceinc
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Hate to ask a dumb question, but how do you get PMs via Audio Asylum?

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 19:27:08
aceinc
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JBen, I have used REW full range, but never analyzing music as it was played. At present I have been using the USB microphone that came with my Emotiva XMC-1. Of course it is not calibrated, and when I posted on the HTS - REW forum about a calibration file, I got crickets.

Since I do not drink coffee, I would need to defer, I could however provide one of a variety of Rums, including two types of Cuban Rum. I often also have Single Malt Scotch around. Perhaps a Fat Tire Beer?

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 19:30:16
aceinc
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Satie, Has anyone tried a mechanical solution to the problem? Something like damping the frame ala the "Razor" technique for Maggies.

Or are you aware of the specific cause of this 12khz artifact?

 

RE: for PM, posted on February 26, 2017 at 21:50:32
JBen
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For PM, you click on the member's moniker and the next screen will show a few things, along with form to send a message. It does depend on whether or not that person allows messages to be sent to her/him.

The message is simple email. The recipients typically reply directly from their email account

 

RE: Adding a tweeter to MMG, posted on February 26, 2017 at 22:46:49
JBen
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No coffee?!!!! Bummer...LOL, I am an eclectic. Just today (as Sunday) they brought me a bottle of my favorite rum...I had a shot right after the Oscars...so, that's covered for the week. Likewise for the Scotch, had some at a friend's on Saturday. However, I don't remember trying that beer...sounds mighty interesting.

These days one can get a new (and useful) calibrated mic for <$20. I'll see if I can bring my portable one to show you.

BTW, analyzing music as it is playing is not usually a practical day-day thing, though it can have some useful applications. I only use it on a comparative basis. For example comparing 1 minute of track X with/without...woofers, or filters or something. It is only as a quick tool. If I need to go further, I use other tools, which I'll show you later.

For example, I only posted some graphs but I actually generated others to cross-reference via another program that same evening. One such is below. Done with another program, it looks at the frequencies present in the digital source file for that same period of 1.5 minutes of Three O'clock Blues. One thing it confirms is that frequencies below 40hz ARE present in the recording, but not as strongly as at 40hz and above. This jives well with what REW "heard" though they are different measurements. One is frequencies. The other (REW) is SPL peaks reached at each frequencies. No rocket science inovolved, though. LOL. If I can do it...



 

RE: Adding a tweeter to MMG, posted on February 28, 2017 at 08:18:11
Satie
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There is no way for damping to make a significant dent in the cavity resonance. It is formed by the physical spacing between the diaphragm and the magnet board. But it has one saving grace in that it does not have a syncronized on axis component. It is entirely random noise on axis so it cancels out as you increase the number of drivers. It is nearly gone at 6 drivers per side and entirely gone at 8 drivers per side. Waveguides can also be used to get cancellation of the cavity resonance peak with fewer drivers. Measurements I saw show it disappearing with 4 driver arrays in an 8" or so waveguide or constant directivity horn.

 

RE: Adding a tweeter to MMG, posted on February 28, 2017 at 13:24:17
aceinc
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Posts: 25
Location: Florida
Joined: February 7, 2017
Satie, what is the shape of the wave guide, or do you have link to further info on this?

 

RE: Adding a tweeter to MMG, posted on February 28, 2017 at 21:53:05
Satie
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Joined: July 6, 2002
Here is the reference. With the CD horn/waveguide, you need to apply EQ to correct for falling response due to the horn geometry of 3db/octave starting about 3khz. CD EQ is a feature of many old electronic crossovers and all digital crossovers.

Report with EQ is flt to 20khz and 3db higher sensitivity which brings you to the mid 90s db.

 

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