Hello everyone, I'm new here, so I hope you will be forgiving of any initial Pecaillo's.
I just got back from the 2015 California Audio Show in San Francisco. That in itself isn't that interesting for DIY'ers, but I discovered that Mundorf is now selling a speaker kit. It comes with a completely Mundorf parts crossover, Mundorf AMT tweeter and Accuton mid-woofer. According to Mr. Mundorf, they needed to be around 40 cm from the back walls, but I'm not sure if that is needed with a sub.
Sadly, the room or the electronics really sucked and I did not hear much I liked there.
I'm wondering if anyone else has experience with the Mundorf AMT tweeters in general? What I am looking for most of all is an endless decay. I'm not sure if this is ever a tweeter's job, but systems that I most like tend to have the ability to show an instrument's or a voice's decay seem limitless. In most systems I hear there's a point where it just gets cut off. This is by comparison, so for all I know there's just a post-signal rigning, but I like it.
This is the main reason I chose an ARC DAC-8 over others in it's price range and above. The end of a plucked string, or the decay in Emilou Harris's voice just seemed to trail off forever. Otherwise, it's like you reach a diode, and bam, off. Sorry for the bad descriptions.
The second thing I need is it has to maintain clarity in a small space. I have Focal's now, but going to a San Francisco apartment I've lost a lot of the clarity they had in my previous apartment, so I think what I want is something with relatively narrow dispersion.
I've also been thinking about a kit from Selah audio, the Verity.
Thanks for your thoughts in advance!
Erik
I just got back from the 2015 California Audio Show in San Francisco. That in itself isn't that interesting for DIY'ers, but I discovered that Mundorf is now selling a speaker kit. It comes with a completely Mundorf parts crossover, Mundorf AMT tweeter and Accuton mid-woofer. According to Mr. Mundorf, they needed to be around 40 cm from the back walls, but I'm not sure if that is needed with a sub.
Sadly, the room or the electronics really sucked and I did not hear much I liked there.
I'm wondering if anyone else has experience with the Mundorf AMT tweeters in general? What I am looking for most of all is an endless decay. I'm not sure if this is ever a tweeter's job, but systems that I most like tend to have the ability to show an instrument's or a voice's decay seem limitless. In most systems I hear there's a point where it just gets cut off. This is by comparison, so for all I know there's just a post-signal rigning, but I like it.
This is the main reason I chose an ARC DAC-8 over others in it's price range and above. The end of a plucked string, or the decay in Emilou Harris's voice just seemed to trail off forever. Otherwise, it's like you reach a diode, and bam, off. Sorry for the bad descriptions.
The second thing I need is it has to maintain clarity in a small space. I have Focal's now, but going to a San Francisco apartment I've lost a lot of the clarity they had in my previous apartment, so I think what I want is something with relatively narrow dispersion.
I've also been thinking about a kit from Selah audio, the Verity.
Thanks for your thoughts in advance!
Erik
My Intimates design now sport the same tweeter the MA30 kit uses. Mid/woofer is a SS 15W Revelator. Below is an on axis FR and 3rd order HD (lower line).
More info at this link.
http://techtalk.parts-express.com/s...with-Mundorf-AMT-tweeters&highlight=intimates
More info at this link.
http://techtalk.parts-express.com/s...with-Mundorf-AMT-tweeters&highlight=intimates
Attachments
Last edited:
Wow, very interesting stuff. Couple of questions. In the level/distortion plot I couldn't quite see what the distortion scale was. Second, I read a lot of technical discussions in the thread, but could you tell me how it sounds relative to others? I'm afraid I don't spend a lot of time listening to tweeters by themselves, but how would you compare it say to a traditional ribbon, or something from Focal or Seas? Thank you in advance.
Erik
Erik
At it's best at higher freq.s - pleated dipole ribbon, and one that extends lower in freq.. Still, that can sound "thin" and "crispy" without the right amplification.
Next: pleated ribbon (rear wave enclosed). (..again, same amplification limitation.)
Dipoles (depending on their baffling) can be narrow dispersion.
Commercially: the Magnepan 3.7i's pretty much epitomize long decays. They need bass augmentation of course, but a dipole DIY sub using GR Research/Rythmik Audio driver's and plate amps can remedy that.
https://www.youtube.com/watch?v=JX6JFMpRiDw
I'm not sure there is anything quite like them in a Kit..
Kit loudspeaker..
http://www.selahaudio.com/kits/
Specifically:
http://www.selahaudio.com/anniversario
Looks like cabinets can be purchased from PE:
http://www.parts-express.com/cat/hi-fi-speaker-cabinets/288
Subs:
3 or more of these sealed in almost 2 cubic feet of cabinet per driver with lossy vents (summed L+R mono):
http://gr-research.com/sw-12-04.aspx
each driven by:
http://gr-research.com/a370peq.aspx
in a "distributed" format around the listening room - preference for multiple listeners, OR
just one directly behind the listener (end table), OR
2 in stereo directly beside the listener (side tables) - preference for a single listener.
Last edited:
Thanks for all the input! I have a 15" Hsu sub already, which is why I'm looking for small bookshelves. I was thinking about the Verity, not the Anniversario from Selah, but it has the same Raal tweeter.
Magnepans are right out in a number of ways, one of which is just floor space. These bookshelves may actually end up on a bookshelf.
Since my second problem is space, I'm not about to start adding subs around the apartment. I may however stack the Hsu sub 4 high....
Magnepans are right out in a number of ways, one of which is just floor space. These bookshelves may actually end up on a bookshelf.
Since my second problem is space, I'm not about to start adding subs around the apartment. I may however stack the Hsu sub 4 high....
Not the same tweeter.
The RAAL (on the Verity) won't have as much extended decay - it's better damped. It's a better choice depending on the amplifier you use and is NOT prone to sounding "thin" or "crispy/whispy" with most amplification.
The ribbon on the Anniversario is pleated design and will have more extended decay (subjectively of course), but again: can sound "thin" with the wrong type of amplification.
Between the two designs the Verity should sound more "sophisticated" - the leading edge of detail a bit more "rounded" with more prominent imaging at the expense of some upper freq. hall sound and "air". The Anniversario: "lighter", "brighter", "faster", "airy".
Note: it's almost never a good idea to put a bookshelf speaker in a bookshelf. Basically you'll want an "in-wall" design for that, otherwise you'll end up with a prominent midrange. (..the best course of action is moving the speaker out into your listening space when it's time to enjoy them.)
Last edited:
The 3rd HD is nominally at the 35 dB level and the fundamental signal is at the 85 dB level. Thus, the 3hd is 50 dB down which equates to less than 1/2% distortion.
How does it sound? Wonderful. Your expectations and mine can't be the same, nor is our hearing. So, I can't really answer that question.
Oh, let me clarify. I'm not looking for an underdamped tweeter that will keep ringing long after the signal had gone, but rather, I want something that doesn't go down to -80 db and then suddenly cut off. That's what I meant by an endless decay. As if the decay ends completely effortlessly and naturally instead of appearing to hit the limits of a diode and cut off.
This isn't about me building a listening room anymore, I'm afraid. This is about me being able to listen in the room. I know where you are coming from, and in my place in Somerville I had a huge living room I could adjust however I pleased. Not true here, so I need speakers that are designed for that instead of an anechoic chamber.
Best,
Erik
I agree with Scott regarding his speaker placement suggestion. All of the audio set up gurus favor having small, stand mounted speakers placed out into a room. It enhances the imaging and soundstage greatly. I suspect your endless trailing off of the highs would also be maximized.
Wow, that's really good.
[/QUOTE]
True, so I think that between different listeners relative differences have less variation than absolute terms, so if a revierwer said "smother than a Focal, but with less extreme high frequency" I would have understood. Whether or not either of us thought that was a plus is another story.
Maybe I'm wrong and even relative differences can't transfer well, but it's all i have got. Thanks for posting all your lab work though. That's great. I didn't realize AMT's had such low distortion overall.
Wow, that's really good.
True, so I think that between different listeners relative differences have less variation than absolute terms, so if a revierwer said "smother than a Focal, but with less extreme high frequency" I would have understood. Whether or not either of us thought that was a plus is another story.
Thanks for posting all your lab work though. That's great. I didn't realize AMT's had such low distortion overall.
Please don't lump all AMT's into one conclusion regarding distortion. The Mundorf AMT's are well built and quite expensive. You can find other AMT's for well less than $100 at Parts Express.
A poster at PETT with the handle pallas created a thread with a link to an NRC speaker test archive and tried to make the case that AMT's fared poorly in a compression (stress) test of one particular speaker. However, the AMT's in the speaker that was tested were obviously custom made for that brand and who knows how well built they were.
Last edited:
Pallas's comments were with respect to linear deviation at lower and higher pressure levels - and though I can't be absolutely certain, most were likely diffraction effects relating to the tweeter's inset into the baffle (..which is something that all tweeters can have a problem with if they are placed to far into the baffle or are "proud" of the baffle.)
It's still best to look at independent measurements of Heil-types though, both for linearity and non-linearity. The biggest problem they have is quality control, and in that respect Mundorf may well be the "best" of the manufacturers.
Yes, my replies are with respect to what you are looking for.
What you need to know with response curve shaping is a thing referred to as baffle step compensation. If the loudspeaker baffle is about 9 inches wide then you have significant pressure loss about an octave below that 9 inch wavelength (which is 1.5 kHz) - beyond a meter. (..so half of that 1.5 results in everything below 750 Hz or so needing a "boost" relative to the higher freq. response). Often then the result is about 4 db of boost at less than 1 meter. (..of course in reality you aren't "boosting" anything, rather you are lowering the output at higher freq.s. - same result, but always creating a less efficient loudspeaker.)
The thing that's important is that the "boost" is NOT needed for an "infinite baffle" condition, and once you place a loudspeaker in a bookshelf then you start getting that sort of "infinite baffle" condition. At that point your normal baffle step compensated speaker will now sound overly midrange prominent with a reduced higher freq. response.
Last edited:
Thanks for all the explanations. I was just trying to explain to Eric that all AMT's are not of the same quality.
With respect to the NRC AMT non-linearity test, from what I understand, those issues arise when a driver is stressed (i.e. played loud) and thermal issues begin to pop up and other non-linearities. It can happen with cone speakers as well as tweeters. The NRC charts show a dB difference between a 'normal' level like 70 dB and a stressed level like 90-95 dB.
I ran a similar type test with my Mundorf AMT 19 CM and got a series of 1-2 dB bumps with a delta of 25 dB.
I'm pretty sure the NRC "deviation" test was not done for tweeters or midranges (..the pressure level is just to low). Basically they are looking for compression with driver's extending into the bass region: specifically excursion related. Of course what they've ended-up with for most measurements is something of a "gotcha" that exposes a deficiency with the construction/design for the tweeters in relation to the loudspeaker baffle.
Scroll down this site listing of measurements (..and though not needed, use an auto-translate in your browser - Chrome has this and if it doesn't work immediately then right click and select the "translate" action.)
??-????????
The tweeter's (that have been tested in this manner) aren't looking at spl-difference deviations in linearity, but rather deviation based on off-set in relation to the baffle. Note how similar they are in relation to the NRC results - specifically where the deviation occurs and to some extent how much of a change in spl there is.
Note that as the tweeters faceplate and the driver membrane becomes more square, that the deviation becomes less regular (..the Neo 3 PDR is a good example). The concentric effect of the deviation is no longer magnified.
What I would ask then is:
Are you sure that with your testing the driver was absolutely flush with no gap between baffle and faceplate (..and that of course it was measured on an "infinite" baffle)?
As you can see from testing of multiple tweeters - just 1mm can make a difference, and it's a difference that's likely to be magnified with level differences.
As for thermals, here is a study done by Johnk:
http://www.musicanddesign.com/VC_heating.html
Last edited:
I'm baffled by that.
It could have something to do with excursion and resonance then.