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Hi-Vi F series V.S. MN series


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32 replies to this topic

#1 of 33 OFFLINE   David Giesbrecht

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Posted September 02 2003 - 10:10 AM

I have been researching these drivers alot and was wondering what the sonic or quality difference was between the F series drivers and the MN sereies drivers? I get the feeling that the F series are more suited towords 2 way applications where as the MN series were developed to work with a midrange such as there 2" DMN.

Any help is much appreciated!Posted Image

#2 of 33 OFFLINE   ThomasW

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Posted September 02 2003 - 12:29 PM

M8a is an outstanding driver. Grab a copy of the current issue of AudioXpress (Sept issue). See (part 1 of a 3 part article) about an easy to build but very high performing 2-way. It uses the M8a and the Vifa XT25. The M series is far better than the little fiberglass ones (F series) IMO.....

#3 of 33 OFFLINE   David Giesbrecht

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Posted September 02 2003 - 02:05 PM

What about the MN series? I understand that the only difference between the Ma's and Mn's is the basket, is the extra cost worth it to go to a cast basket verses a stamped one? the cost difference is about double.Posted Image

#4 of 33 OFFLINE   ThomasW

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Posted September 02 2003 - 03:20 PM

Yes the performance is close but not identical. Compare the specs on the M8a and M8n. The differences are probably due to the Mn series being shielded. But as a result one can't just exchange a M8n for a M8a if the XO has been optimized for the M8a.

#5 of 33 OFFLINE   David Giesbrecht

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Posted September 02 2003 - 04:44 PM

Considering the specs are very close and the response curves are pretty much identical, I think I'll stick with the MN series. The price difference is much to large for a cast basket that really doesn't appear to add any performance to the driver.

[quote] But as a result one can't just exchange a M8n for a M8a if the XO has been optimized for the M8a. [quote]
Not a problem for me (Hypex active home amps) Posted Image

BTW: What do recomend for a tweeter to combine with two M6N's in a sealed box and a DMN dome midrange? I have been looking at a few options such as the 3/4" Vifa XT tweeter, the Focal TC90TD5, or the Hi-Vi RT1C-A Planar.

Any thoughts?

#6 of 33 OFFLINE   ThomasW

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Posted September 02 2003 - 05:30 PM

[quote] BTW: What do recomend for a tweeter to combine with two M6N's in a sealed box [quote] I wouldn't use those drivers. Their Xmax (3.5mm) is too small for them to handle any significant amount of power. That's why we design with the 8" driver, it's Xmax (5.8mm) is much more usable. And it's larger VC (1-3/8") allows it to dissipate more heat.

BTW using a sealed box makes the M6n's short Xmax even more problematic.

#7 of 33 OFFLINE   David Giesbrecht

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Posted September 02 2003 - 05:40 PM

[quote] BTW using a sealed box makes the M6n's short Xmax even more problematic. [quote]
Are you sure I would need to use 2 M8N's? that seems a little exessive to me, the speakers I have now are a single 8" with only 2.3mm Xmax in a sealed box and they play quite loudly.

BTW I will be using a high pass network on them @ 80 hz so I don't need any low end extension.

#8 of 33 OFFLINE   ThomasW

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Posted September 03 2003 - 02:45 AM

When Jon and I design, we chose drivers that have solid output to atleast one octave below the intended XO point. That guarantees there's no hole in the frequency response and protects the driver during high SPL's. This means that a midwoofer should have good/safe output to 40Hz if the XO point is 80Hz. Obviously you can use any driver you want.

#9 of 33 OFFLINE   David Giesbrecht

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Posted September 03 2003 - 02:11 PM

How would I line up the ZDP on an M series driver or a dome, should I just build test boxes and use an SPL meter? Obviously I don't want to introduce any passive components to the speakers signal to adjust for phase differences (kind of eliminates the point of active XO's).

#10 of 33 OFFLINE   Andrew Pratt

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Posted September 03 2003 - 03:26 PM

David I've never heard the other model but I can't believe how solid my M8a sounds. It can play low and have impact but where it really shines is how smooooooth the midrange is with this unit. No doubt some of that has to do with Jon's XO design but its an awesome driver.

#11 of 33 OFFLINE   ThomasW

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Posted September 03 2003 - 03:34 PM

David 1)One can't properly measure loudspeaker performance with a SPL meter. They simply aren't accurate enough for the job. One needs a calibrated microphone, good mic preamp, and a software program like JustMLS, Clio, Praxis, etc. 2)Generic active XO's aren't suitable for powering active speakers. They lack things like baffle step compensation and slope adjustability that are necessary for proper voicing of the speaker. 3)Use of active XO's doesn't guarantee phase coherence, and one can certainly have phase coherent speakers with a passive network. Jon and I built and marketed several models (2-way and 3-way) in the mid 1970's that would reproduce a square wave. These utilized all passive XO's These are a few of the reasons I suggested building the M8aMKIV. That speaker was designed, engineered, built and tested with more than $250,000 worth of equipment. Do yourself a favor, buy the Sept issue of AudioXpress magazine and read the article. It is literally a treatise on proper DIY loudspeaker development.

#12 of 33 OFFLINE   David Giesbrecht

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Posted September 03 2003 - 04:54 PM

[quote] 3)Use of active XO's doesn't guarantee phase coherence, and one can certainly have phase coherent speakers with a passive network. [quote]

I releize that they don't guarentee phase coherence. But the phase is relitave to driver phase response and listener distance, right? So if you aligned the phase with a measurment tool at the XO point they should be phase accurate, I think.Posted Image

Thomas

I am not questioning your knowledge on the subject I'm just trying to understand what the best solution for me is because I have read alot of articles which contridict each other and sometimes the advice given here so to say the least I'm a bit confused sometimes as to what is the right way to do things.

#13 of 33 OFFLINE   ThomasW

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Posted September 03 2003 - 05:47 PM

Unfortunately no 1/3rd octave RTA is adequate to the task of measuring driver frequency response for designing a speaker. The measurements are not fine enough to see the level of detail necessary for designing and there's no way to eliminate driver/room interaction. Also one needs to measure an impedance plot of each driver being used in the system, those measurements can't be done with an RTA.

One should use (MLS) Max Length Sequence measurements to isolate the driver output from it's interaction with the room.

Dan and the rest of the crew at Adire certainly know that XO's need things like baffle step compensation to properly voice a speaker. Note that subwoofer to mains XO's don't need this type of compensation. But it's mandatory between midwoofers and tweeters.

[quote] So if you aligned the phase with a measurment tool at the XO point they should be phase accurate, [quote] To create a phase coherent system one starts by physically aligning the acoustic centers of the drivers to within +/- 0.5mm on the baffle. This means a stepped or sloped baffle.

BTW, IMO there are more important things than phase coherent systems........

Understand that I'm not trying to rain on your parade. Am just trying to get you to understand how complex it is to do proper speaker design. One can't simply look at a catalog of drivers and pick and choose according to a budget.

Here's a link to a thread that discusses a small fraction of the work involved in the M8aMKIV design.

And here's a link that details info about the Vifa XT25 tweeter.

These threads are but a tiny part of the actual magazine article.

#14 of 33 OFFLINE   Michael R Price

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Posted September 04 2003 - 08:03 AM

David... Even if you spend some money and have to save up more before you can design your own speaker... build a professional design first. Really. I've only built one pair of speakers (Kit281)... and even though I'm the kind of person who would like to come up with something new... I think my next speaker will be a professional design as well. The design really is a big deal.

#15 of 33 OFFLINE   DarrenK

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Posted September 05 2003 - 04:35 AM

Hi, Regarding the MN series versus the F series... I have used several of the MN's, and have been pleasantly suprised. The M5N is a nice little driver that produces pretty good bass in a medium sized vented enclosure. It is very strong in the midbass and doesn't have some of the frequency response anomolies that many other drivers have in this region. The M6N is a good driver, though it has its first breakup rather low for a 6" driver, hence making it more difficult to use in a two-way. The first breakup in the M8 series of drivers is at almost the same frequency, so if you're going to go through the trouble of making a lower XO point, you probably ought to just use the 8". Regarding the differences between the MN and the MA series. I have done extensive testing of the two series, including distortion and frequency response tests and found no differences between the two. The only discernable difference I could find was in the cast vs. stamped frame, which at half the price for the stamped, is a no-brainer. Also, I'd like to make note that neither the M8N or the M8A are shielded. So, back to the MN vs. the F... the F's are probably easier to work with from an XO standpoint. If you like detailed and slightly metallic sound with strong bass, then I would go with the MN series. See ya! Darren

#16 of 33 OFFLINE   ThomasW

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Posted September 05 2003 - 04:58 AM

[quote] If you like detailed and slightly metallic sound [quote]
so it follows that carbon fiber woofers sound 'carbony', fiberglass woofers sound 'glassy', paper woofers sound 'papery', and kevlar woofers sound kevlary.

Whatever...........Posted Image Posted Image Posted Image

#17 of 33 OFFLINE   DarrenK

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Posted September 05 2003 - 07:32 AM

Hi ThomasW, Oh, you're right, sorry about that. I forgot that all cone materials have the same characteristics and sound the same. I'll have to remind the driver manufacturers and the finished speaker companies that they should just stick to one material and save all of their efforts. See ya! Darren

#18 of 33 OFFLINE   Michael R Price

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Posted September 05 2003 - 09:37 AM

Maybe they sound metallic if the breakup peak isn't properly controlled?

#19 of 33 OFFLINE   DarrenK

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Posted September 05 2003 - 09:54 AM

Hi, Yes, the crossover used is most definitely of the utmost influence on the ending sound. Most of the "metallic" sound is due to a couple major breakup modes that is pretty much inherent in that material. With a proper crossover, you can eliminate most of these resonances, and make them much less metal sounding, possibly even not metal sounding at all. But, considering the crossover that the average person will design, chances are some of these resonance peaks will still be hovering around. I'm not saying they are overly "metallic" and annoying, but in most cases will have a slight amount of "metal" flavor to them. In the design I'm working on, they sound quite good, and if it weren't for using a metal dome tweeter, you may not even be able to tell there's metal in the speaker at all. Gotta go, have a great one! Darren

#20 of 33 OFFLINE   ThomasW

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Posted September 05 2003 - 12:03 PM

Darren

It was just a joke so please chill Posted Image

If you look at the FR plots from drivers like the Eton kevlar their break up modes are very similar those of the metal Hi-Vi. To my ears they simply sound 'transparent'

We've have more than 1/2 dozen operational M8a variants in the pipline for almost 18 months and no one has commented that they have a metalic sound. Perhaps it's Jon's 48dB/octave XO.




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