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MT-121 Not completly Satisfied - Mysteries

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levyte357- View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Topic: MT-121 Not completly Satisfied - Mysteries
    Posted: 16 April 2016 at 9:39am
I think the results some get from MTs, really depends on drivers used, quantity of cabs, flattening eq.

But also think is pointless exercise, unless LMS is used.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote matty w Quote  Post ReplyReply Direct Link To This Post Posted: 16 April 2016 at 8:44am
Listen to bee .. Why people imagine that your gonna get a decent sound out of the mt 12" horn above roughly 1.2/1.3/1.4 is beyond me lol well tbf I went down the same road so can't really speak haha !

It is what it is !! High pass at 150hz and low pass at 1k tops IMO !!

Find a driver that will play flat down to around 1k for the top end !

No good trying to bump a load of eq in the crossover regions either !
The filters will mess around with the sound anyway , .... Getting drivers that meet each other properly is halve the battle on getting a good sounding speaker !!

18 sound 1464 is what I used ... Does the job nicely !

Also worth mentioning the 12" horn is a bit of a problem when you only have one a side, doesn't cut the mustard IMO ... For these speakers to shine , you need two either side !!!

Also you need dsp ... It is a must !!

Don't consider all of these points and they will never properly work !!!

Sound good on some tracks but not others hahaha!

They might sound ok to some people whilst not adhering to this advice but one day you will realise u wasted a lot of time and money !!

And you really do need an expensive quality 1.5" comp or a 2" with some bullets or 4592!!
Black to black , red to red , blue to bits ....

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Post Options Post Options   Thanks (0) Thanks(0)   Quote LeruSound Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2016 at 5:39pm
Thanks to each and every one, u all were so nice giving me your advices. Finally i made L-Pads with around 3.5 dB of att., and i'm good with them now, or at least better than before. I found the 1" driver not so bad in that combination. It gives a bright character to the sound, and make it enjoyable and exciting. 

Originally posted by bob4 bob4 wrote:

I have measured a MT121 loaded with Fane 12". It had a big dip (=hole) between 600 - 1000 Hz that needs a lot of EQ.


I heard about the same problem. Some ppl who wanted to made crossover on them from an audio shop, finally had the x-over around 700-800 hz cause it was not possible to rise over in that horn. So i'm pleased that this is not hardly happening on mine. 

But the same question: which driver u would use to load this project? 
http://hornplans.free.fr/pas5ma1.html
It is quite different from MT121, but i personally would choose that 12NMB420.


Edited by LeruSound - 04 January 2016 at 5:42pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 14 December 2015 at 12:45pm
oh, and maybe you should read this:

Which specs should I look for in a driver for midrange horn use?



Edited by bob4 - 14 December 2015 at 12:46pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 14 December 2015 at 12:32pm
Originally posted by LeruSound LeruSound wrote:

I just found another one that gived me good results: 12NMB420 from 18sound.. I think i will go with them.


Don't do it! You can use what you already have. Several people have given you the same, good advice. If you follow it you will get good results.

I have measured a MT121 loaded with Fane 12". It had a big dip (=hole) between 600 - 1000 Hz that needs a lot of EQ.

The measurement of your MT121 looks very nice compared to that! The 12" plays well up to the crossover frequency. But as others pointed out, the 1" driver is playing too loud! That is your main problem! 

Like Marjan and others said, you should:

1) decrease the level of your 1" driver. (2 - 4 dB)
2) use delay to time align 12" and 1"

Easiest solution: Get rid of the passive crossover and use separate amplifiers for 12" and 1", use a DSP like behringer DCX for time and level alignment.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote fede Quote  Post ReplyReply Direct Link To This Post Posted: 14 December 2015 at 10:29am
You need to attenuate hf frequencies.. The lf driver is not your problem, if you can, use an active crossover. Send me a pm, maybe I can help you!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LeruSound Quote  Post ReplyReply Direct Link To This Post Posted: 01 December 2015 at 4:17am
I just found another one that gived me good results: 12NMB420 from 18sound.. I think i will go with them.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LeruSound Quote  Post ReplyReply Direct Link To This Post Posted: 01 December 2015 at 3:15am
I will For sure. Try get a look to B&C 12CL64. It seems good to me for this experiment.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 01 December 2015 at 12:55am
Changing drivers to achieve more low frequency capability (heavier cone, more excursion) will be a trade-off because you will most likely lose midrange efficiency, transient response and reduce the upper usable limit.  You will also be running below the cut-off frequency of the horn, which means that you won't get much more output than the driver in a sealed box with no horn in front of it.

Are you calculating the Fc just for the driver in the sealed rear chamber?  If so then of course you will see lower cut-off frequencies for different drivers.  When you take the horn into account as well, that has a much larger influence over the low frequency response because you will get no benefit from it below it's operating range.

Your options are probably to either have more horns together which will help the efficiency at the low end or just to apply some gentle EQ to flatten the response down to your crossover point.

Can you do another measurement of the MT121 on it's own, with no crossover on high or low please?




Edited by ceharden - 01 December 2015 at 12:56am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LeruSound Quote  Post ReplyReply Direct Link To This Post Posted: 01 December 2015 at 12:12am
Originally posted by ceharden ceharden wrote:


Back on-topic, I still don't think the 18Sound driver is the issue.  To be honest, I think you might have slightly unrealistic expectations of what this cabinet will produce.  It's a horn designed to do a fairly narrow frequency range and dispersion.  You won't get much low end from it, no matter what driver you use.  The sealed rear chamber will control and limit the excursion.




Love the way u replied me. I think we could be in the same wavelenght :D
Sorry for the poor english but i'm from italy and i'm not using translators for improove.
So, i think that a driver which gives the system an Fc around 200 Hz , cutted 180 Hz cuold be worse than a driver which gives the syestem an Fc around 100 with the same 180 Hz cut.
Mine is now at 200 Hz. Some of you r suggesting me to use others that gives me Fc again around 200 Hz.
I am suggested to use one that gives me Fc around 100, 120 - 140 could be also good for me. Maybe i will have a better punch on it? Dont u think so?
Selenium enginners seemed to thik the same in PAS5MA1. In MT121 the same. Probably the horn will kill what i am trying to get from the 12", but it could be better than before, dont it?
I will compensate from 3 dB the HF drivers, because i would not do it anymore with eq until it seems to be so unbalanced. 
If u think i am so wrong please try to stop me, but give me your opinion, and please try to debate with me but in order to get a practical solution. Why it should be so stupid to provide under 200 Hz response? Will the horn kill the 100 200 Hz band completaly? Do you think it could be useless? Why in PAS5MA1 and MT 121 the plans are planned in order to handle that 100 hz from the rear closed chamber? 

Now it sounds like a conspiracy topic or something that can be heard in Tv at late night Shocked


Edited by LeruSound - 01 December 2015 at 12:18am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LeruSound Quote  Post ReplyReply Direct Link To This Post Posted: 30 November 2015 at 11:54pm
I will reapeat it: i am not trying to hear 100 Hz from that horn!! I am just trying to get the best HPF result on the 12". 
Maybe i went wrong posting that plot and spending too much time on the HF section. I will fix that problems for sure, but i would like to talk about the mismatch i hear from people in stead of what the designer wrote on the suggested drivers in the plan.
Volume of the rear closed Chamber = 17.5 L (MT121)

You tell me 12PE32 is good but Qtc=0.47 Fc=226 Hz told me u cut it around 150 HPF
  12NDL76 is good but  Qtc=0.46 Fc=200 Hz told me u cut it around 150 HPF
  12MB700 is good but Qtc=0.5 Fc=198 Hz told me u cut it around 150 HPF

Plans tells   SN12MB  is good     and Qtc=0.77 Fc=107 Hz It is suggested to a 160 Hz HPF
  12MB1P is good     and Qtc=0.82 Fc=103 Hz It is suggested to a 200 Hz HPF
  12PLB100 is good     and Qtc=0.71 Fc=96 Hz I thik it as a choice 180 Hz HPF
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bee Quote  Post ReplyReply Direct Link To This Post Posted: 30 November 2015 at 11:48pm
plus 1.....
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