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Pd121 a bit too weak in my 4 way system ? |
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raspix 
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Joined: 02 December 2009 Location: Paris, France Status: Offline Points: 63 |
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 Topic: Pd121 a bit too weak in my 4 way system ?Posted: 26 May 2015 at 1:32pm |
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Hello,
I'm currently in the (long) process of building my setup. It consists of a pair of HOGs, a usb, 2 MT130s and separate CDs. I've done my math to estimate each way's output to see who'll be the limiting factor, and it turns out it's the mids (which isn't a real surprise). I've got, @1m for RMS power ratings, 133dB on subs, 131dB on bass, 127dB on mids, and 130dB on highs. It's a roots sound system, I've already done this for all rounder installations where I need pretty flat responses, but in this case I don't really know what to look for. Obviously the subs have the most output so whe're good with that, but a 7dB difference between subs and mids tends to scare me a bit, it'll be rapidly dangerous to try to keep up with the rest pushing the mids over their limits. So should I choose other speakers for the MT130 build, or does it seem okay ? Good afternoon guys |
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app
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Joined: 26 December 2013 Location: Finland Status: Offline Points: 2435 |
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Posted: 26 May 2015 at 1:40pm |
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The human hearing is most efficient in the himids (about 4khz) which would be good in your case.
Those are just numbers. Best thing is to use your ears and find a good balance for your system. Your system is as good as its weakest link. You cant push anything over,makes no sense. If the mids are "weak" you should IMO setup according to them. Not go full power on subs and destroy your mids  |
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"what!?"
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raspix
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Joined: 02 December 2009 Location: Paris, France Status: Offline Points: 63 |
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Posted: 26 May 2015 at 2:42pm |
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Already having the subs and not the mids, I'd like to optimize my system ! I've seen beymas 12MI100 being talked about, would they fit the Mt130 well? I'd get 130dB @1m, close enough for me
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Teunos
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Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Posted: 26 May 2015 at 3:30pm |
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If you really think that the 3dB difference will conpensate for what you experience as a lack of mid, you might get very disappointed when moving to different drivers.
More likely is that this is a combination of several other factors such as a general wrong frequency response of your current system, strange dips due to phase cancellation, high(or low) distortion percentage. Etc. etc. I would first find out what the real problem is. Also, how did you measure that dB figure? Surely with an uncalibrated spl meter which can only register up to 130dB, with a very unflat frequency response and also measured at a single frequency in the passband of each driver? |
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Best regards,
Teun. |
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levyte357-
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Joined: 27 July 2012 Location: UK, South East Status: Offline Points: 8128 |
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Posted: 26 May 2015 at 3:56pm |
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One of the problems on this site, is some people spend too much time theorising, as opposed to listening to speakers first, tuning,then making decisions.
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Global Depopulation - Alive and Killing.
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raspix
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Posted: 26 May 2015 at 6:28pm |
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I'm sure I haven't made myself clear: I ave the bottom half of the stack, and thought that my near built Mt130s would be better off with other drivers, partly due to a lack of power. I'm a live sound engineer, so as I was saying I've been dealing with general use pa, but concerning my sound system playing roots I was a bit caught off guard. My method is to calculate the gain at ems power, 10log(400) for instance, and add it to sensitivity, so I get a rating at 1m. When finalized, I will take the time to work my system, listen, tweak, no worries about that. I actually share your point of view. thanks for your time
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Teunos
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Joined: 23 November 2008 Location: The Netherlands Status: Offline Points: 1799 |
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Posted: 26 May 2015 at 6:37pm |
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Well in that case i'm sure that this rough estimation of SPL will give you a basis to start of with. I'd say that is more than ample. Being a roots sytem you will probably be short at least 10dB in the sub range anyways, i highly doubt the mids will be the lacking part.
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Best regards,
Teun. |
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Mark James
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Joined: 15 January 2006 Location: rig side Status: Offline Points: 5309 |
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Posted: 26 May 2015 at 6:47pm |
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+1 id want to double the bass before i upgraded the mid tops tbh
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me so horny me love you long throw
horn loaded for her pleasure |
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levyte357-
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Posted: 26 May 2015 at 6:52pm |
I've heard PD121s/PD123s in 6x MT121s, cover over 2,000 people... So IMHO, maybe time to re-examine use of MT130s. |
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Global Depopulation - Alive and Killing.
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fatfreddiescat
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Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1083 |
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Posted: 26 May 2015 at 7:42pm |
Why are you asking this question????????
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raspix
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Posted: 26 May 2015 at 8:05pm |
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Well because I've never been anywhere close designing a system for such a specific use, I wasn't asking about technical data, just thoughts on how you estimated your system and what it translated into. Thanks for your answer concerning the sub, this two sub basis will be, I hope, the first of many
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fatfreddiescat
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Posted: 26 May 2015 at 9:12pm |
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Your PD 121's will easily keep up with the low end and would do so as direct radiators, no horn required, with them being horn loaded you will have plenty of headroom room to add more lows
 I wouldn't at this stage be too concerned about the dB figures but would be looking at what HF and waveguide that will play low enough not to compromise the xover point to much and also match the radiation angle at the xover point. |
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Mark James wrote: