oscilloscope overkill?

[anger 10+ year member]

This isn't exactly a technical question, but not sure where else to post it. I added some new pieces to my setup and have been wanting to tune it with an o-scope. Not wanting to purchase one, I've been going to local shops and checking pricing on having them do it. But when I ask if they have an oscilloscope they say..."a what?".

They all claim to do it by ear...so to the question. Is tuning with the o-scope kinda 'overkill' for an average setup? or are these shops full of lazies/unknowledgeables?

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[jasonbillnelson 10+ year member]

Tuning with an O-scope will show you visually whether you are clipping or not. O-scope tuning is a great way to tune so you have a clean unclipped signal going to your woofers. I don't own an O-scope so I tune with a Digital Multi-Meter to get proper RMS output from my amp. I intend on buying an O-scope in the future.

 

[Full Tilt 10+ year member]

In my personal opinion, there's no such thing as overkill when it comes to your subwoofer's safety. Most average shops don't exactly have a good reputation to enthusiasts because most of them only sell mainstream product at crazy prices (which may be necessary to stay alive in this business nowadays when you're restricted to a smaller area), and their lack of knowledge. That's where 'tuning by ear' may come into play. A lot of kids working in these shops barely understand the concept of clipping, much less are actually able to detect the slightest trace of it by sound. I really wish more shops had o-scopes, because then they'd realize how dirty a lot of the power they sell really is.

 

[calebkhill 10+ year member]

Dude...

Stay away from shops.....

 

[anger 10+ year member]

Dude...Stay away from shops.....

Ya, that's the feeling I'm getting. Found out I paid almost double at a shop, than I could've elsewhere, for my amp. So, one last question. Any recommendations for a scope, hopefully under 3 bills? Do I just need to make sure it will read the frequency range I need? DD-1 better option? (guess that's a few questions)

Thanks for the input.

 

[calebkhill 10+ year member]

Your right.

DSO Nano at Amazon. 60$ oscope. Works like a charm

 

[Sub Woofin 10+ year member]

its not over kill for any setup imo.

 

[anger 10+ year member]

sweet. thanks again ppl!

 

[maylar 10+ year member]

You gotta understand that the vast majority of systems being installed are just upgrades from stock. An experienced installer can do it all by ear. It's only us "enthusiasts" who want to squeeze every clean watt possible out of our amps. I would only expect a shop that did competition systems to have a scope.

 

[calebkhill 10+ year member]

That's true and all but people left and right go home and burn their ***** up

 

[trumpet 5,000+ posts]

anger, where in Southern California are you located? Maybe I can direct you to a reputable shop for an installer you can trust.

That's true and all but people left and right go home and burn their ***** up

So your logic is don't go to a shop because the individual is most likely going to burn their **** up regardless?

 

[T3mpest 10+ year member]

Only in car audio are gains set by O-scope. Gains if being done for a real setup that plays music, should be set by ear. The point of a gain is to match various speakers in SPL relative to one another, not to run everything everything to it's max unclipped output. Also, 99% of cars, without any clipping are quiet if you play good music wih dynamic range. So no, a good shop, unless they are doing SPL builds has no real need for an O-scope for gain setting, it's not rocket science and your ears and common sense will do a better job than a O-scope since it's the actual acoustic output you should be concerned with.

Even if your going to run around blaring bass head music all day, you'll generally get more output with some clipping than without, and unless your already overpowering the woofer that's generally pretty safe to do.

 

[Jepalan]

Only in car audio are gains set by O-scope. Gains if being done for a real setup that plays music, should be set by ear. The point of a gain is to match various speakers in SPL relative to one another, not to run everything everything to it's max unclipped output. Also, 99% of cars, without any clipping are quiet if you play good music wih dynamic range. So no, a good shop, unless they are doing SPL builds has no real need for an O-scope for gain setting, it's not rocket science and your ears and common sense will do a better job than a O-scope since it's the actual acoustic output you should be concerned with.
Even if your going to run around blaring bass head music all day, you'll generally get more output with some clipping than without, and unless your already overpowering the woofer that's generally pretty safe to do.

I respectfully disagree, point for point, with almost everything you wrote above.

1) O-scopes are used for gain balancing in all kinds of professional audio installs, including high-end home audio, concert halls, and studios.

2) The point of gain setting is to:match speakers AND to optimize signal to noise ratio through the system, AND to set peak levels to the *desired* clipping point

3) In my *opinion* a reputable shop should own an O-scope, know how to use it properly, and use it on every install to set gains.

4) There are many things that can go wrong when setting only by ear (and many things that can be corrected by a critical ear). In my opinion, o-scopes and DMMs ensure you are starting with the optimal baseline before using the ears to fine tune everything. For example, it is can be difficult to set optimal signal levels when multiple devices are being daisy chained (like LOC to DSP to AMP) and they all have gain or input pots.

 

[T3mpest 10+ year member]

I respectfully disagree, point for point, with almost everything you wrote above.
1) O-scopes are used for gain balancing in all kinds of professional audio installs, including high-end home audio, concert halls, and studios.

2) The point of gain setting is to:match speakers AND to optimize signal to noise ratio through the system, AND to set peak levels to the *desired* clipping point

3) In my *opinion* a reputable shop should own an O-scope, know how to use it properly, and use it on every install to set gains.

4) There are many things that can go wrong when setting only by ear (and many things that can be corrected by a critical ear). In my opinion, o-scopes and DMMs ensure you are starting with the optimal baseline before using the ears to fine tune everything. For example, it is can be difficult to set optimal signal levels when multiple devices are being daisy chained (like LOC to DSP to AMP) and they all have gain or input pots.

I agree on a few things here, sort of.

1. If you have alot of inputs before your amp an O-scop can make it easier to set the gains for those. However, it's hardly critical as while doing it by ear may not totally maximize S/N ratio, you can usually get it to be quiet enough to not hear the noise. That's really all you need, any quieter is kinda excess for obvious reasons.

2.Shops should use DMM's for 1 reason only, minimize warrantee issues, that's it! That's more or less where this absurd idea came from in the first place.

Here is my contention, realize when people here about gain setting with an O-scope, they are almost NEVER talking about preamps/input sides. Most people just have a HU going to an amp going to speakers. That's it, we both know where the O-scope is going, the amps outputs! You can test where you HU clips for the sake of knowing, but beyond that the O-scope has no job in an install like that.

People use O scopes to eliminate clipping, that's the idea, as somehow ANY clipping has become the devil on here. No clipping whatsoever.. Now what if we are listening to classical music? Average crest factor in classical is on the order of 20db. (crest factor is the difference between average volume of a track and it's maximum, for those unaware) If your refusing to clip and have a 100 watt amp on your speakers, they will see right around 1 watt of power for most of the song.. See the problem yet? If you system isn't going to clip, then you better have amps with AT LEAST 2x the power the speaker claims to need. That's fairly expensive and again, not what most people are doing. Granted most people aren't listening to classical either, but there is plenty of well recorded music that has well over 10db of crest factor. Anyone who has music from the early 90's probably has some, early days of the CD were very good in this respect.

Let's look at how most people would setup gains with an O scope on the output side. They'd find the clipping point of each amp and then HOPEFULLY, turn down anything that is now too loud. Granted, that step seems like it's often forgotten. However, even doing this, you can see we've further decreased overall listening levels for the sake of fidelity. Not always a bad thing, but when you started with a bad premise to begin with.. Road noise, low amp power and you refuse to clip. (again most people here are matching RMS on speakers to amps fairly closely, that's not cutting it on good music without clipping)

Even modern music has between 6-14db of crest factor. If your getting near 6db, then yeah, you probably don't need to clip very much ie avenged sevenfold, but 14db can usually stand a fair bit of clipping and will require it to get your max output that will still sound the same without damaging equipment. It all comes back to what you listen to. Now to throw another wrench into it, some people listen to music in cars from different sources. Alot of those can be several DB's quieter than others too. Again, another reason to give yourself some range on the output side. There was a thread on here just a week or two ago with someone who said things sound great with their CD's, but there phone's MP3's are just too quiet.. Everyone's response, spend more money! Boost your signal, stop using the phone, etc, etc. NOBODY brought up turning the gains up some and the HU down on your CD's, not a single person for 2 freaking pages. That's how brainwashed some people are to setting gains with a machine.

Lastly, you mentioned setting things to the "desired" clipping point. I can't imagine doing that with a scope. Setting your output to clip with a scope is ridiculous. How would you even know when to stop? At that point, using your ears as a judge seems far more sensible.

 

[calebkhill 10+ year member]

Good discussion.

I understand what y'all are arguing.

On one hand, clipping isn't useful to the average person fur various reasons.

On the other hand we are trying to save equipment bt.

That's the point, to save equipment.

Now, when you say, "a shop tunes by ear because the scope is overkill for the average person".... it would be true, but shops don't even know what a scope is to begin with. So that's not the reason, "because it isn't applicable to the average system", they don't use one because thet don't know what it is. Which strengthens the point that "shops don't know *****" And they don't.

And they don't know sht. I asked Kar Tunes to scope mine, they said what's that.

I asked Jimmy Car Stereo "what's the crossover point on those passives", the only Memphis tweeter he sold. He didn't know. And when i mentioned 3.5khz is normal in passives, he said "ono, that's to low"

That's just a couple examples.

I'd be scared to let a shop install, say, 4000 watt system. Let's clip some subs and amps at that power.

Overall, the point is. Customers pull out the parking lot and burn up equipment. Shops need to use a scope or dmm and let the person know when they cross the line.