Velodyne SMS-1 Problem PLEASE HELP!

You'll need to run a Stereo RCA cable from Velodyne "EQ Output" to any Stereo Input in your AVR (i.e CD In). Then select in your AVR that input in order to get the Test Tone signal. To get the test tone signal press "Menu" on the remote and "1-2-3-4-5"

I'll recommend you read this guide:

www.velodyne.com/pdf/sms-1/sms-1_guide.pdf

Yes!!! Everything is correct. The test tone signal goes out from the "EQ Output", not from the LFE Output. That's why you are not getting any test tone signal.

Again, I'll recommend you read first the OutLaw SMS-1 Guide....

Don't use the SMS-1 to set levels. It's not an SPL meter. Don't turn your sub down that much unless you're sure it's set that much too high.

To set the subwoofer's gain setting, first set the SMS-1's Volume to 15, (15 is "Unity Gain".) Then, use an SPL meter and the receiver's internal test tones to calibrate the speakers and sub. Those will be the proper calibrated levels. Then, proceed to the SMS-1 EQ process. Once you've finished EQ'ing, then come back and adjust the SMS-1's Volume to get the final output back to the proper calibrated level.

Craig

Go back and do the process I described. An SMS-1 level setting of 65 is *way* too high.

You have 3 "Volume Controls" that impact the final output of the subwoofer: 1. the subwoofer gain setting; 2. the receiver's subwoofer trim setting, and 3. the SMS-1's Volume setting. You want all of these settings in their "mid-band" settings so you are not over- or under-driving the next "stage" of the system.

An SPL meter is fine for setting the subwoofer gain and receiver trim. The receiver's test tones are 40 to 80 Hz "noise" tones, so your SPL meter will be fine for the pre-EQ receiver trim settings. Set the subwoofer gain so you get a subwoofer trim setting, (in the receiver) of about -3, with an SPL meter reading of about 75 dB.

Then proceed with the EQ process. Adding boosts and cuts will affect the overall "system gain", so when that process is finished, you go back and set the SMS-1 gain, (i.e., the Volume setting) to the correct calibrated level.

Craig

PS. Are your graphs just the sub, or are the speakers on as well?

Also, what receiver do you have?

You have your volume set really high on the SMS-1. I have mine set at 32 and it is very powerful. My sub levels are set at about the 11 o'clock position. Attachment 232747

If your graph shows the speakers and subs, you have one of the 3 subwoofer volume settings I described above set way too high. Also, it's not surprising that the subwoofer SPL is "spiking." Something is set way too high.

To fix this, set the SMS-1 to 15. Set the receiver's subwoofer trim setting at "0" or "-3". Then use the gain setting on the subwoofer to get the SPL meter to read ~75 dB. You may need to run through a few "cycles" of the test tones to get there, but persevere until you get it right. This step is very important.

Then proceed with the EQ process. You should end up with the SPL above the crossover very similar to the SPL below the crossover.

Craig

BTW, here is a very old post that describes how I used the SMS-1 in my system:
http://www.avsforum.com/avs-vb/showt...5#post11731755
It has a lot of detail that may be helpful to you.

Craig

Do all of the steps I suggested BEFORE you do any of this ^^^. You need to start out with a calibrated system BEFORE you begin the SMS-1 EQ process. Once you've done the steps I described in Posts 9 and 13, you can begin the SMS-1 EQ process as you and the manual describe above.

If you do things the way I suggest, and then do the step you describe above, you will end up with both the speakers and sub displayed on the SMS-1 output AND the levels will be set properly. The goal is to have the speakers' output above the crossover point, (80 Hz?), the same as the subwoofer's level below the crossover point. There will be some peaks and valleys, but the average level of the speakers and sub should be close to the same.

In your graph, the subwoofer's level below 80 Hz is WAY higher than the speakers's level above 80 Hz:



You need to bring the subwoofer level down and the speaker level up so they are closer to the same BEFORE you go any further with the EQ process.

Craig





4:30 central time tomorrow I will proceed with your advice. Thanks John.[/quote]

The dip at 80 Hz could be a small cancellation between the speakers and sub at the crossover. Try adjusting the subwoofer distance setting in your receiver. Write down your original setting so you can get it back if this doesn't work.

The dips above 80 Hz can't be corrected with the SMS-1. They're caused by the speakers and the SMS-1 only EQ's the subwoofer. You can try playing around with speaker positioning to impact them.

The first graph you posted was better than the 2nd. I would keep the subwoofer level at 16. It looks too high at 21. You want a flat line all the way across the screen.

The Q setting widens or narrows the effect of the filters. Instead of bunching multiple filters together, try using one filter with a wider Q, (lower number.)

Show me a pic of Page 2.

Craig

OK, I forgot you posted the settings previously.

I can't predict the optimal setting for Q for any given filter. Q is the width of the filter. The default is 4.3, which is 1/3 octave. The lowest setting is 0.3, which means the filter covers 3.5 octaves, or basically the full range of the subwoofer. The highest setting of 20 equates to a 1/12 octave, or a very narrow filter. I would try replacing the 3 filters you have bunched together around 60 Hz with one filter with a wider Q, maybe 2.0 or so. Experimenting is the only good answer here.

To adjust Q, select a filter and scroll down to Q. Select it and adjust up or down.

Another thing you can look at is just the sub's response without the speakers. Adjust that to be as flat as possible and then add back in the speakers. This will help you "see" the interaction between the speakers and sub.

Craig

Flat response is the goal, so if switching polarity gives a flatter response, then that is the right setting. However, instead of switching polarity, try adjusting the subwoofer distance setting in the receiver. The distance setting is a delay setting with much finer incremental control than 180 degrees of phase/polarity shift.


If you use the SMS-1 Volume Control to decrease the total average output, then small boosts will have an insignificant impact on the amps or on driver excursion. What you want to avoid is stacking filters close together with wide Q's and then adding boost to both of them. This WILL challenge the amps and drivers.


My "guideline" is to avoid more than 3 dB of boost and 6 dB of cut. The boost rule is pretty firm, and I rarely break it, and then only if the system has considerable headroom. However, there are times when you need more cut than 6 dB. In those cases, be as judicious with the cut as possible while still hitting your goal of flat response.




Craig

You are probably used to heavily cooked bass and getting your system in proper balance probably does sound lacking to you. However, I would encourage you to listen to your system for a while with the new settings. I think you'll come to find that there is a lot of detail in the bass that you were missing before and that the "flat" settings will ultimately be more enjoyable. You can always use one of the Presets to set up a "hot" setting if you really need it.

Craig

That is unnecessary. The fact that the SMS-1 doesn't give absolute level (no, it's not an SPL meter) is utterly irrelevant for the task of setting relative levels between mains and sub. Test tones from the AVR are going to be unduly skewed by peaks and nulls in the response of both mains and subs.

I agree with setting the SMS-1's volume to unity gain (15) and then using the level control on the sub to bring the sub up to the level of the mains*, but otherwise a better procedure is as follows:

(1) turn subs off, and set SMS-1 to 15.
(2) start running sweeps on the SMS-1
(3) turn up the volume on the AVR such that there's a fair bit of room above and below the graph of the mains.
(4) turn on first sub (the closest one to the mains) at minimum gain, and gradually bring up its level using the control on its own amp* such that it's more-or-less the same as the mains.
(5) Adjust the phase control on the SMS-1 or the sub (or the distance on the AVR) for smoothest response
(6) If one only has one sub, go to Step 7. If one has a multisub system,. then change the above steps to have the bass lagging by a few dB, and repeat steps 4 and 5 for the second sub (though, obviously, only using the controls on the sub itself), then repeat steps 4 and 5 for the third sub, until one has no more subs.
(7) Start playing with the EQ to get the smoothest response and the desired house curve.

*unless one is running amps with quite high input sensitivity (pro amps, but also some consumer ones such as the NHT A1 and knockoffs) and the AVR doesn't put out much juice. Then the SMS-1 will have to be used as a line driver. Also, some subs (e.g. KEF HTB2, NHT Verve) don't have level controls. Then the SMS-1 will be used in place of level controls. Obviously, to use such subs as part of a multisub system one needs to add some sort of line-level attenuator to all of them (except the first sub calibrated) at least.

An octave is a doubling of frequency. So 20 to 40 Hz is one octave and 40 to 80 Hz is another octave Obviously 1/3 of 20 to 40 Hz is a "smaller" range than 1/3 of 40 to 80 Hz. However, they both have the same filter "width." If you have a narrow peak, then use a narrow Q filter to reduce it. If you have a wide, broad peak, then use a wide Q filter to reduce it.

Never use a wide Q boost to try to raise a null or valley. Nulls, true nulls, are always narrow, and boost doesn't usually correct them anyway. Adding more energy to a cancellation just causes more cancellation. It's not worthwhile to try to boost nulls, and it can be dangerous to your subwoofer.

As long as you limit the boost you apply to 3 dB, you shouldn't need to be concerned about damaging the sub.


Another thing you can do to augment the bass is to just turn up the SMS-1 Volume Control. If you know your "baseline" setting, you can always go back to that. Then, if you want to run 3 dB "hot" just turn it up 3 dB. You do need to be a little more judicious with the receiver's Master Volume Control, but that could give you the extra output you want.


I don't mind helping out a Vikings fan, but being a Vikings fan right now can't be easy.

Being a Packers fan, OTOH...

Craig

I read this thread with great interest as I'm considering purchasing the SMS-1. However, I'm not sure if I would like it or not.

A little background; a little over a year ago I purchased an SVS EQ-1. While it seemed to do a good job giving a flat response, I really didn't like what I heard, or more accurately, what I didn't hear (low bass seem to disappear). Even playing good classical recordings the low bass didn't sound anything like I've heard in a live concert; removing the EQ-1 sounded closer to "live" to my ears.

I would have thought that I would have preferred a perfectly flat frequency response, but after my experience with the EQ-1, perhaps the reality is that I just don't like a flat bass response. Since the EQ-1 doesn't offer any manual or user customized settings, I returned it.

This brings me to my interest in the SMS-1. It seems from what I've been reading I can set my own preferred curve if it like, for example, if I wanted a smooth rise from the crossover frequency down to the lowest frequencies?

Benclement11, it seems when set to the flattest response, you also didn't care for the result. Were you able to come up with a setting that you liked? Has the SMS-1 been pretty easy to use, or has it caused much frustration?

Might the SMS-1 be what I'm looking for, or am I more likely to be disappointed based on my experience with the SVS EQ-1? Am I better off with another product?

If another thread would be more appropriate for my questions, please let me know.

For reference I'm using a single SVS 16-46PC+ powered cylinder sub.

Thanks.