MT121 comp driver probs
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=106249
Printed Date: 22 March 2023 at 12:24pm
Software Version: Web Wiz Forums 12.05 - http://www.webwizforums.com
Topic: MT121 comp driver probs
Posted By: biggins
Subject: MT121 comp driver probs
Date Posted: 25 April 2021 at 7:25am
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Hi there, I'm hoping someone can help me troubleshoot an issue that i am having with some comp drivers in MT121. Originally, I had the cabs loaded with P-Audio BMD750 and was seeing an issue where the audio dropped off steeply arund 10Khz. I thought the BMD-750s
were crapping out above 10k because they are 2" comp drivers and apparently that is A Thing. To try and rectify the situation, I picked up some BMS 4555. However when I measure the new comp drivers driver using REW I am still seeing a pretty steep drop off around 10K. * Measurement of BMS 4555 (laptop > soundcard > amplifier > BMS4555):  * Measurement of BMS 4555 (laptop > soundcard > processing > amplifier > BMS4555)processing is just some EQ to smooth stuff out ~~~~~~~~~~~~~~~~~~~~~~~~~~
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Replies:
Posted By: biggins
Date Posted: 25 April 2021 at 7:37am
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OMG, trying to get images to display. Faaark....
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Posted By: fatfreddiescat
Date Posted: 25 April 2021 at 9:20am
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Looks like a normal response for a constanrt directivity waveguide, here's a link to a previous discussion that cove rs this topic: https://forum.speakerplans.com/radial-vs-constant-directivity_topic44930.html" rel="nofollow - https://forum.speakerplans.com/radial-vs-constant-directivity_topic44930.html
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Posted By: MarjanM
Date Posted: 26 April 2021 at 12:44pm
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First of all you can not put 1.5 inch exit driver to a 2 inch throat horn. I mean you can, obviously, but it will have issues. Second, just add a highshelv eq above 10Khz and it will be way better. ------------- Marjan Milosevic MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
Posted By: levyte357-
Date Posted: 26 April 2021 at 3:49pm
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Also the 2" horn is very important.
Been easily getting upto 16khz, with Beyma CP750TI, with B&C ME60 & ME75 Alum horns. But they are decent, not Cheap sh*t. I also have approx 12x EV HP940 horns, which are best I have ever heard, but will not be going anywhere.  ------------- Global Depopulation - Alive and Killing. |
Posted By: levyte357-
Date Posted: 26 April 2021 at 3:55pm
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Make life easy, try using decent comps with fairly flat response chart upto 12khz. Then add correcting eq as suggested by Marjan. Beyma cp755nd as used in some Void tops, are smooth, loud, go plenty above 12khz. ------------- Global Depopulation - Alive and Killing. |
Posted By: biggins
Date Posted: 27 April 2021 at 10:17am
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Hi, Thanks for the replies all. Lots of info to digest in the Audio Heritage thread in the thread shared by fatfreddiescat. I think that will take a few sittings to digest. MarjanM & Levyte357 - Thanks for the replies. I'll have a play about with the High Shelf EQ.  MarjanM - Sorry, I'm gonna be that guy and ask The Question. Why would you not put a 1.5 comp driver on a 2" horn (using an adaptor)?
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Posted By: gcaDIY
Date Posted: 17 May 2021 at 3:16pm
totally okay with making it easy using decent comps.
What models of Void tops do you mean exactly? Which ones use that Beyma compression driver? Thank you very muchAnt. |
levyte357- wrote:Posted By: levyte357-
Date Posted: 21 May 2021 at 1:21pm
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Can't remember exactly, I'm not a Void groupie, Staysis something.
But combinations I've used personally for years. B&C DE85 + B&C ME60 Beyma cp750ti 2" + B&C ME60 or ME75 Alu horns, Beyma cp750ti 2" and Paudio PH4525 In a nutshell, get rid of BMD750 Beyma 750ti probably best of the budget 2". ------------- Global Depopulation - Alive and Killing. |
Posted By: smitske96
Date Posted: 21 May 2021 at 3:32pm
| I would also look at the RCF ND950. 4" VC with still a good response higher up. |
Posted By: cravings
Date Posted: 21 May 2021 at 8:01pm
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think it was the porn horns used that beyma comp... not technically a void product, more like a rog / pro audio parts product. i think that porn horn high horns are in the void stasys phil now, but i don't know what comp is on them. |
Posted By: levyte357-
Date Posted: 21 May 2021 at 11:27pm
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One of the Staysis tops, also uses Beyma CP755Nd 1.5".
Heard them in a Reggae Dance, could not quite believe my ears. I'm sure Void engineer was there that night, and set the Void LMS, they were using.
------------- Global Depopulation - Alive and Killing. |
Posted By: levyte357-
Date Posted: 22 May 2021 at 9:00am
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I don't know of many great 1.5" horns, but there are loads of good 2", so I've stuck to 2" comps.
Paudio PH4525, sounds great with many makes of 2" comp, with corrective eq for 12khz+. Sounds better than JBL 2380A that costs a fortune, and breaks so easily. As said previously, I have 12x of the EV HP940, which maybe similar to the Porn Horn 2" horn, and I've heard them do 16khz+, with JBL 2450.
------------- Global Depopulation - Alive and Killing. |
Posted By: cravings
Date Posted: 22 May 2021 at 7:33pm
| Could not believe your ears cos it was good, or bad? |
Posted By: levyte357-
Date Posted: 22 May 2021 at 8:53pm
Was ultra smooth, bullets type sizzle, without bullets !! ------------- Global Depopulation - Alive and Killing. |