Mini-dsp input voltage and its limitations. - Page 2 - AVS Forum
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post #31 of 39 Old 11-03-2013, 09:17 PM - Thread Starter
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Originally Posted by paskal9 View Post

additional information:
if you're still clipping the minidsp input when the avr trim is 0, might wanna change the input sensitivity. minidsp have 0.9v and 2.0v if i remember correctly. try and change it and see if you still clip the input. i can't remember what mine is set at but i did experimented with it.

+0 trim at the avr shouldn't drive the minidsp input to clipping. if you still have it the something is wrong. check it first then we'll continue from there.

AVR is set to -7 sub trim for a 75 db cal at 0 AVR volume using AVR noise.

As it stands now, as noted in post one, I have ~ -15 db of headroom on the mini input. But, if I want to run my subs hot 10 db I drop down to ~ -4.5 db of headroom. Not so much a problem right? Wrong.....

Each time I boost that takes from the headroom too. (that might be elementary for some, it was not for me). SO that leaves me 4.5 db of headroom which could easily be long gone depending on content being fed to the system.

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post #32 of 39 Old 11-03-2013, 09:27 PM - Thread Starter
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Originally Posted by andyc56 View Post

Now, I'm not excusing the miniDSP's lousy dynamic range and p-poor documentation.

However, there is a situation here in which the maximum output of the AVR is boatloads higher than the maximum input of the miniDSP that follows it. Pflughaupt's article assumes a wet dream scenario in which all circuits hit clipping at once as the input signal is increased. This scenario is physically impossible in this particular case. Short of putting an attenuator at the AVR output, the miniDSP will always clip before the AVR out does. Any procedure, such as the one in his article, whose purpose is to steer the result to try to achieve this physically impossible scenario of simultaneous clipping of all outputs is bound to result in a sub-optimal configuration when the target scenario is unrealizable.

Had to think for a second, on who the hell Pflughaupt is.... hah... now I remember. It's Wayne, the writer of the HTS article.

Really, I've read more times than not the point is to get the AVR, or first piece of equipment in the chain, to clip last. That way you'll never be sending a clipped signal down the chain.


All I really wanted to bring up here was exactly what you started this post with, and I just got done typing it on the mini-dsp forum about an hour ago.

I only posted my numbers and notes I spent considerable time taking last night here to help back up what I, and as noted in my first post, others have stated.


I get there's work arounds etc..... I just think the entire mini-dsp, as neat as it is, is amateur hour. From the time you open the box from the time you start to really learn about it's inner workings.

Hell,.... just tonight someone posted again.... what power supply should I use... really? Minidsp still can't get the word out? Amateur hour....... tongue.gif Then again I guess it is kind of a DIY type product.... maybe it's so neat people expect too much? I dunno.....

good night smile.gif

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post #33 of 39 Old 11-04-2013, 04:14 AM
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Originally Posted by pdxrealtor View Post

Had to think for a second, on who the hell Pflughaupt is.... hah... now I remember. It's Wayne, the writer of the HTS article.

Really, I've read more times than not the point is to get the AVR, or first piece of equipment in the chain, to clip last. That way you'll never be sending a clipped signal down the chain.


All I really wanted to bring up here was exactly what you started this post with, and I just got done typing it on the mini-dsp forum about an hour ago.

I only posted my numbers and notes I spent considerable time taking last night here to help back up what I, and as noted in my first post, others have stated.


I get there's work arounds etc..... I just think the entire mini-dsp, as neat as it is, is amateur hour. From the time you open the box from the time you start to really learn about it's inner workings.

Hell,.... just tonight someone posted again.... what power supply should I use... really? Minidsp still can't get the word out? Amateur hour....... tongue.gif Then again I guess it is kind of a DIY type product.... maybe it's so neat people expect too much? I dunno.....

good night smile.gif

So with the many documented issues with the MiniDsp, can you recommend a different, less troublesome EQ devise that can do what the MinuDsp can do, while not costing a fortune?

I am saving up to buy some Behringer iNuke1000dsp amps for my LCR's and an iNuke3000dsp for my subs. I believe that the iNukes will give me great power, and the ability to EQ my setup with out having all of the problems assisted with a MiniDsp, although I did order a balanced 2x4 MiniDsp last week to tinker with, haven't decided if I want to keep it.
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post #34 of 39 Old 11-04-2013, 01:07 PM - Thread Starter
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Originally Posted by Martycool007 View Post

So with the many documented issues with the MiniDsp, can you recommend a different, less troublesome EQ devise that can do what the MinuDsp can do, while not costing a fortune?

I am saving up to buy some Behringer iNuke1000dsp amps for my LCR's and an iNuke3000dsp for my subs. I believe that the iNukes will give me great power, and the ability to EQ my setup with out having all of the problems assisted with a MiniDsp, although I did order a balanced 2x4 MiniDsp last week to tinker with, haven't decided if I want to keep it.

I'm not familiar with the iNuke amps, or any amps for that matter, with dsp in them so I have no idea how they would compare to the minidsp.

For me, if I don't end up needing the delay/crossover settings in the mini I will not be using it as there is a real concern for over driving the inputs to clipping. Can it be setup properly with 'bandaid' techniques, sure. There are so many variables on the input/output side one must really understand how it all works to ensure proper setup.

Until mini-dsp can put together a manual that documents some of the more complex **possible** issues one might run into and how to deal with those issues.....I don't want to use it.

Again, I suggest people read these links, don't browse , read, (the DIYAudio link in particular has a lot of great factual technical info) some of which has been corrected by minidsp. But it still leaves the not so educated people like myself walking away with more questions than answers.

http://www.diyaudio.com/forums/minidsp/230470-signal-level-minidsp-x-over.html

http://www.avsforum.com/t/1443652/minidsp-require-signal-boost-with-pro-amps/0_100 <--- in post 14 even Ricci explains a bit about the minidsp and it's inability to easily be added to the signal chain in some instances.

http://www.avsforum.com/t/1281290/minidsp/1100_100#post_22711797

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post #35 of 39 Old 11-06-2013, 07:24 AM
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^^^

So what you are saying is that you bought a low cost solution, are confused when it doesn't work as you expected it to, and then feel the need to vent on a forum degrading all the work they have done? The miniDSP provides a ton of options for little $. You need to be willing to deal with the limits of a low cost and high value solution in a positive way. If not, you need to look at a higher cost / high value solutions in order to reduce your frustrations. The same thing applies to people buying the clone amplifiers.

The miniDSP isn't perfect, the but level of vitriol you seem to be having is not unwarranted.

I must be guilty because people say I am guilty because they chose to call me guilty because they refuse to see the truth. Much easier to be part of the mob..
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post #36 of 39 Old 11-06-2013, 01:30 PM - Thread Starter
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Originally Posted by Trepidati0n View Post

^^^

So what you are saying is that you bought a low cost solution, are confused when it doesn't work as you expected it to, and then feel the need to vent on a forum degrading all the work they have done? The miniDSP provides a ton of options for little $. You need to be willing to deal with the limits of a low cost and high value solution in a positive way. If not, you need to look at a higher cost / high value solutions in order to reduce your frustrations. The same thing applies to people buying the clone amplifiers.

The miniDSP isn't perfect, and the least they could do is provide some instructions and documentations so that a lot of it's target audience is aware of some of its limitations. Then people like you would not get so frustrated and feel the need to voice their frustrations constructively in an open forum

I fixed that last half for you. wink.gif

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post #37 of 39 Old 11-06-2013, 01:52 PM
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I fixed that last half for you. wink.gif

I don't believe the "target audience" is the amateur or novice. The fact that enthusiasts with basic knowledge can use the device I think speaks volumes (pun intended) about the product. Maybe their long term goal is a broader group. But based upon their pricing, they need the community (e.g. crowd sourcing) to help them out. That is my point.

Your frustration in palpable. That is evident. Dealing with quantization and scaling when going through multiple A/D and D/A stages will always be frustrating to some degree. When you want really wide dynamic range, the issue compounds itself. Hope tings work out for you though. smile.gif
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I must be guilty because people say I am guilty because they chose to call me guilty because they refuse to see the truth. Much easier to be part of the mob..
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post #38 of 39 Old 11-06-2013, 02:02 PM - Thread Starter
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Originally Posted by Trepidati0n View Post

I don't believe the "target audience" is the amateur or novice. The fact that enthusiasts with basic knowledge can use the device I think speaks volumes (pun intended) about the product. Maybe their long term goal is a broader group. But based upon their pricing, they need the community (e.g. crowd sourcing) to help them out. That is my point.

Your frustration in palpable. That is evident. Dealing with quantization and scaling when going through multiple A/D and D/A stages will always be frustrating to some degree. When you want really wide dynamic range, the issue compounds itself. Hope tings work out for you though. smile.gif

Thanks.... they always do in the end.

I would say one thing about your words above RE: the target audience.

If you follow the the couple of different mini-dsp threads that are active on just this board, you will see questions being asked that clearly prove a large portion of the buyers and potential buyers are beginners and have a lot of basic questions when it comes to eq, dsp, signal chain, even balanced cable questions.

How are they to know about input clipping and proper headroom in the dsp if they don't even know how to make audio cables, or what Q does, etc... ?? A lot I see don't even have the desire to learn about the cables they just want to hook it up, run REW, and auto eq to be done.

And .....that goes for me too. I'm just as new to a lot of this stuff. I just happen to have OCD and the need to know how stuff works. smile.gif
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post #39 of 39 Old 11-18-2013, 03:41 PM
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Originally Posted by pdxrealtor View Post

Thanks.... they always do in the end.

I would say one thing about your words above RE: the target audience.

If you follow the the couple of different mini-dsp threads that are active on just this board, you will see questions being asked that clearly prove a large portion of the buyers and potential buyers are beginners and have a lot of basic questions when it comes to eq, dsp, signal chain, even balanced cable questions.

How are they to know about input clipping and proper headroom in the dsp if they don't even know how to make audio cables, or what Q does, etc... ?? A lot I see don't even have the desire to learn about the cables they just want to hook it up, run REW, and auto eq to be done.

And .....that goes for me too. I'm just as new to a lot of this stuff. I just happen to have OCD and the need to know how stuff works. smile.gif

Reading through this when searching for information on the MiniDSP, and for all the functionality of the product, the issues about voltage and cabling are the single biggest reason I haven't bought one yet. Let me explain...

I have a Denon 4311 AVR with MultiEQ XT32 and Audyssey Pro.. My system has Mythos ST mains, a CS-8080 HD center, Gem XL surrounds, and two HSU ULS-15 subs. The mains and center are powered, with a woofer section that you can run either as LFE input as a faux sub, or you can run these speakers as a single speaker, with the signal carried on speaker wire. All my LFE/sub connections are currently unbalanced RCA types.

However, I'm toying, based on the suggestion of some guys on my REW/HDMI thread, with going the Geddes "more bass, even with less capable subs, is better" route, and using the Mythos ST LFE inputs, the CS-8080 LFE input, and my two real subs in some manner to ultimately get a better overall bass response with frequency response and more importantly bass decay rates.

Having said that, the MiniDSP 10x10 in a box, and the 10x10 plug-in, would be perfect. I could put the two real subs and the three woofers on LFE, set separate levels, and matrix them into one or more sub channels as output (which I can always run on a Y-adaptor as a single output from my AVR if I want). That way I can manage delay and levels within the MiniDSP for the individual (or grouped) subs, experiment with different high shelf filters for the channel or channels input from my powered speakers (example: maybe I use a steeper high shelf filter to minimize distortion from my powered center, which only reaches to about 40 Hz, than my powered mains, which can reach more like 25 to 30 Hz), even set some crude house curves on the final output once Audyssey is done. Plus the MiniDSP has multiple presets, which facilitates experimentation.

In a way I'd have more flexible functionality than from either Sub HT EQ, where you can set distance and trim for only two independent sub channels and then EQ them as one (vs. a more interesting approach with an AntiMode or MiniDSP for > 2 subs before you do the final "EQ as one"), or the Audyssey Pro Kit, with its +/- 3 db Target Curve Editor.

But...I get bogged down about the need for XLR cables, creating your own Phoenix cables, and the issues with what voltage to set. For me, the naïve thinking is that since all my inputs are RCA and unbalanced, there's no issue, and connect away on the units unbalanced input/output. Yet, I see a lot of advice that you should go balanced, and tweak voltage for your own situation. And I don't want to blow out my subs with gear designed for pro audio/DIY enthusiasts rather than home audio consumers.

Reading all that, I don't feel comfortable buying a MiniDSP unless I was a lot more DIY than I am with voltage boards and creating my own cables, which I could care less about with my focus on the unit's versatility. Is there really a straight forward answer to this, like you only need to play with voltage if you have some high-powered Emotiva amp, XLR inputs, and DIY stuff? And that as a consumer, there's no risk in taking the plunge as long as I don't start running REW sweeps at 95 db or something?

Stuart

 

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