Print Page | Close Window

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: 28 November 2022 at 7:38am
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
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

  

~~~~~~~~~~~~~~~~~~~~~~~~~~
 
My expectation (hope) was that the 1.5" comp drivers would behave better above 10Khz but that's not what i am seeing. The comp drivers are attached to a P-Audio P2723 2" horn (with 1.5" -> 2" adapter).

So, I'm a little stuck as to how to proceed. I'm wondering if the issue is being caused by the P2723 horn. Maybe i f'ed up and bought the wrong horn and i need to buy different horns? However, before I spend more $$$ on new horns/shipping, I wanted to get a 2nd opinion on the above issue cos maybe I am missing something or maybe there is some more troubleshooting i can do..

If it is the horn, can anyone give an opinion on the BMS2230 horn or the B&C ME60 paired with the BMS4555? Am also open to other suggests.

Thanks in advance
B

Links:
Comp Driver: http://www.bmsspeakers.com/index.php?id=bms_4555
P-Audio Horn: http://www.paudiothailand.com/pac/index.cfm/products/product/?id=566

BMS 2230 horn: https://www.thomann.de/intl/bms_2230.htm
B&C ME60 horn: https://www.thomann.de/intl/bc_me_60.htm



Replies:
Posted By: biggins
Date Posted: 25 April 2021 at 7:37am
OMG, trying to get images to display. Faaark.... Confused


Posted By: fatfreddiescat
Date Posted: 25 April 2021 at 9:20am
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


Posted By: MarjanM
Date Posted: 26 April 2021 at 12:44pm
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
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.LOL


-------------
Global Depopulation - Alive and Killing.


Posted By: levyte357-
Date Posted: 26 April 2021 at 3:55pm
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
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.  Thumbs Up

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)?


Posted By: gcaDIY
Date Posted: 17 May 2021 at 3:16pm
Originally posted by levyte357- levyte357- wrote:

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.



Hi! 
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 much

Ant. 


Posted By: levyte357-
Date Posted: 21 May 2021 at 1:21pm
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
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
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
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
Originally posted by cravings cravings wrote:

Could not believe your ears cos it was good, or bad?

Was ultra smooth, bullets type sizzle, without bullets !!  


-------------
Global Depopulation - Alive and Killing.



Print Page | Close Window

Forum Software by Web Wiz Forums® version 12.05 - http://www.webwizforums.com
Copyright ©2001-2022 Web Wiz Ltd. - https://www.webwiz.net