MT121 revisited, revised
Printed From: Speakerplans.com
Category: Plans
Forum Name: MT122
Forum Description: Discussion / Questions about the MT122
URL: https://forum.speakerplans.com/forum_posts.asp?TID=49892
Printed Date: 01 October 2023 at 9:10am
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: MT121 revisited, revised
Posted By: pfly
Subject: MT121 revisited, revised
Date Posted: 14 March 2011 at 2:23am
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As many know, MT122 plans on the main site are bit misleading and confusing. Also I think this type of midtop doesn't necessarily need 18mm outer shell, since that's just what it is, shell or rack where real acoustic pieces are bolted into. To kill some time I redrew the horn, this time completely from 15mm ply. This thickness will be enough for outer panels and at the same time will make tricky horn assembly a bit easier with its larger joint surfaces. It should also theoretically dampen the horn a bit more. I also removed mitre angles of over 45 degrees. To do this, I needed to make the whole thing few cm taller. This makes back chamber slightly larger. Other alteration that may have slight acoustic difference to the original is that I also replaced speaker baffle and horn throat baffle with 15mm ply, so there is sliiiightly more volume in compression chamber. I hope I got all important dimensions covered in these pictures. Missing information can be measured from Sketchup file. Please let me know if something importand cannot be derived from dimensions already given in pictures. I also hope this will make it easier to build more MT's as I believe these are very very nice basic mid horns for the price, only put off by their build difficulty. Here is a ZIP file with pictures with measurements and .SKP file for Sketchup http://dl.dropbox.com/u/9726318/mt121/mt121_15mm.zip - http://dl.dropbox.com/u/9726318/mt121/mt121_15mm.zip    Have fun -Mikko |
Replies:
Posted By: mikey bear
Date Posted: 14 March 2011 at 2:35am
cracking work! much appreciated 
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Posted By: Aztor
Date Posted: 14 March 2011 at 1:26pm
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Thanks. The revised version is easier. Is it possible to create a phase plug for the MT121 ? |
Posted By: t.geessounds
Date Posted: 14 March 2011 at 3:10pm
| am tryin to open the file but it dont want to open??? |
Posted By: pfly
Date Posted: 14 March 2011 at 4:03pm
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It's a ZIP file, Windows XP, Vista and 7 should be able to open them by themself, but you can also use WinZip or WinRar to open zip files. If you mean the .skp file inside .zip, it is Google Sketchup 8 file. |
Posted By: MarjanM
Date Posted: 14 March 2011 at 4:28pm
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You need to have Sketchup installed to be able to open it. ------------- Marjan Milosevic MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
Posted By: graftak
Date Posted: 14 March 2011 at 4:41pm
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Do you have The Hr data for this with the altered rear chamber and front chamber.. Cheers, Graftak
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Posted By: pfly
Date Posted: 14 March 2011 at 4:52pm
| To be honest the differences are so small that HR can't show anything relevant. Difference in back chamber size is about the same as choosing between ferrite and nd magnet. |
Posted By: graftak
Date Posted: 14 March 2011 at 6:37pm
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thanx for your reply, ( and i could always put a little piece of extra wood in the chamber...) anyway bloody nice job making the cab eazier to build. Cheers, Graftak
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Posted By: graftak
Date Posted: 15 March 2011 at 1:35pm
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is there any chance you could save this as an Sketchup 7 file. Cant find a free version of sketchup8.. Cheers
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Posted By: djeddie
Date Posted: 15 March 2011 at 1:59pm
http://sketchup.google.com/download/gsu.html - Looks free to me! You only have to pay for the "pro" version... which is bound to be on any number of 'warez' sites in the next couple of days. ------------- Chas n Dave : it's like Drum and Bass but with beards. E=mc² ±3dB |
graftak wrote:Posted By: Tibor23
Date Posted: 15 March 2011 at 2:26pm
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Thanks man, greta job. this is realy usefull:D ------------- S.O.K. |
Posted By: eltron
Date Posted: 15 March 2011 at 3:05pm
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djeddie beat me to it! you can get pretty far with the free version imo. I had a one year license of the 7 pro, ended up not using most of the "pro" features - the only useful one is dwg import/export. |
Posted By: graftak
Date Posted: 17 March 2011 at 1:42pm
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yes but I cant open this plan in the free version, it said I need version 8. something... Cheers, Graftak
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Posted By: eltron
Date Posted: 17 March 2011 at 6:31pm
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Yes, the current (yes, free) version is 8, downloadable on the site posted above. Also it seems like you can install 8 parallel with 7 nowadays, just checked on two different systems, mac and win xp pc.
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Posted By: collision
Date Posted: 08 January 2012 at 4:35pm
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what driver did you adapt this plan for? would a pd123er work well in it? thanks ------------- ONE LIFE. AVE IT. |
Posted By: smoore
Date Posted: 08 January 2012 at 11:10pm
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Yea can anyone make a list of compatible/recommended drivers for these plans? Or similiar T/S parameters would probably be more useful. I have eminence alpha 12" drivers and was looking at building. Top stuff anyway!
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Posted By: PuppaBB
Date Posted: 09 January 2012 at 8:56am
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And PD 12MH25? ------------- www.facebook.com/PuppaFran www.facebook.com/CrucialRuler www.facebook.com/DUBFever |
Posted By: vibez
Date Posted: 10 March 2012 at 11:31am
| I have mt122's and mt121's and have tried many drivers in them but have been most happy with bms drivers, i had to alter chamber size slightly from the original design that is on this site but results were very good in my opinion. I haven't had a close look at these new dimensions but would advise anyone building mt's to check out bms available from Tony Wilkes on here. |
Posted By: fat_brstd
Date Posted: 28 December 2012 at 10:47am
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I would like to build some of these over summer but dont really want to have to work out how sketch up works so was wondering if anyone had a pdf of the designs and maybe a cut list so I can start working out how many sheets of ply im going to need. ------------- Melbournes Rootical Warrior Roots - Dub - Steppers http://www.facebook.com/adrians.wall" rel="nofollow - facebook page |
Posted By: pfly
Date Posted: 28 December 2012 at 11:33am
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the .ZIP file should have all dimensions needed in JPEG format. I don't have cutlist, that you need to work out yourself. |
Posted By: pfly
Date Posted: 28 December 2012 at 12:09pm
This comes a bit late apparently: Really, differences of few cubic cm and millimetres here and there won't really make this that different to the original Rog Mogale MT122/MT121, everything said about the original applies for this redesign also, the point of my redesign was to just make it easier to build. |
Posted By: UpComingSound
Date Posted: 04 January 2013 at 3:39pm
| If any one can help me out, question I just purchase the B&C 12pe32 for mt121 and am using the ashley protea 4.8sp for crossover what should i set the cross over settings at ? HPF freq and LPF freq right now I have the HPF at 150 and LPF at 2000 |
Posted By: LjudLahger
Date Posted: 04 January 2013 at 3:46pm
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Nice work!
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Posted By: UpComingSound
Date Posted: 05 January 2013 at 4:35pm
| If any one can help me out, question I just purchase the B&C 12pe32 for mt 121 and am using the ashley protea 4.8sp for crossover what should i set the cross over settings at ? HPF freq and LPF freq right now I have the HPF at 150 and LPF at 2000 is that a good xover setting? |
Posted By: cravings
Date Posted: 05 January 2013 at 4:51pm
| can't get my MT121 12" sections to go much higher than about 900hz... |
Posted By: pfly
Date Posted: 06 January 2013 at 1:58pm
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Slight update: I made a version with a space for horn and compression driver, the cutout I drew is for 18Sound 1,4 to 2 inch XR series horns but there is enough space for example JBL 2380 series of horns. https://dl.dropbox.com/u/9726318/mt121/mt121_twoway.skp" rel="nofollow - https://dl.dropbox.com/u/9726318/mt121/mt121_twoway.skp  |
Posted By: soundchippy
Date Posted: 06 January 2013 at 2:47pm
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thanks plfy! i'm going to make it my summer project to finally build and test one of these. |
Posted By: scss
Date Posted: 03 April 2013 at 5:22pm
| Does Anyone Know If The Fane Sov Pro 12-500 Will Fit / Work Well In This Cab? |
Posted By: pfly
Date Posted: 03 April 2014 at 6:07pm
Update from other thread:
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Posted By: bozhidar
Date Posted: 07 March 2016 at 6:00am
| Hello! The driver I want to put inside the single MT121 (without the horn) is 155 in total depth. How can I modify the back chamber to fit it in? How much space do I need between the magnet and the backdoor? Right now there is 145 MM from the baffle to the backdoor. |
Posted By: Miles
Date Posted: 19 August 2017 at 9:54am
 4 mt121 bulit after the 15mm plan by forum member pfly - give thanks for providing the plan - first audio measurements and thing looking good! |
Posted By: T-Bone
Date Posted: 23 August 2017 at 12:50am
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The later 2 way version in 15 mm with CD top, isn't this MT121 40X25 degree dispersion? So I would need 4 per side for 160 degree splay? I am thinking JBL 2386 2" horn with a JBL 2450 CD? Thanks for the input, 12PE32 is what I am going to use. ------------- BASS, how low can you go! |
Posted By: bob
Date Posted: 30 July 2018 at 5:57pm
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Hello, can you please reupload the plan? Would be very helpful!
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Posted By: Archi
Date Posted: 01 June 2019 at 8:23am
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Hi all, I've been lurking here for a while and ready to build MT121 next week Lots of pics of MT121 has been removed or gone also the zip file in previous discuss , I need more information(like flare angles) before I start it. Could anyone send me the file? I'll thank you thousand times! |
Posted By: nejten
Date Posted: 15 March 2020 at 11:41pm
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Hi everyone, I can't open any of the links posted. Can somebody help me with this? Bless ------------- From small acorns oak trees grow. |
Posted By: lola_handycam
Date Posted: 29 March 2022 at 12:35pm
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Same here i would love to get the dropbox files, do anyone has the file somewhere in their computer ?? cheers
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