sms1 sub levels

Hi all ,loving this unit, my question is:if I have the level of the test tone thru my fronts at say 80 db according to the radio shack spl meter what should I set my sub level at? 80 also, I know this sounds like a dumb question. but i'm just wondering the proper way to do it. I have my subs betwen 1/4 and 1/2 like it says in the manual and with the test tone on it kind of flattens out around with the volume at 30 to 34 on the sms1. does it sound like I'm doing it right?

If you have the volume of your processor up so that the mains are showing around 80dB or so on the frequency response screen, then all you need to do is keep the response curve level to the left and you'll end up with the sub adjusted to the correct level. With so many places to adjust the sub level (sub amp, processor, and SMS-1), it does get a bit confusing, but I simply set my sub's volume nob at around 1/2 and set the sub trim on my processor around 0dB (I had it at -4dB previously), then left it up to the SMS-1 volume control to handle the rest.

thanks Gonk, but my question is, should there be a certain db level that the subs should be, my thinking is fronts 80 db sub 80 db or should I just adjust the sub volume to what i like{I like good bottom end} be not boomy, but I want the subs to kind of match the fronts, I mean I went thru the response chart in the eq and the fronts are pretty good down to 40 hz.

If the mains are 80dB and the curve is flat, then the sub is 80dB as well - that's the nature of the curve. Having said that, I'd suggest calibrating to 80dB and adjusting to taste (up or down).

Thanks again Gonk thats what I thought, By the way how are you making out with your unit

I'm quite pleased with mine - even got a review up here /

very informative review, hope I was a bother with all the questions

Nice review Gonk. So is the slope supposed to be set at 0 if the SMS crossover is off then?

If I remember correctly, as soon as you set the crossover to "OFF" the slope also reads "OFF".

gonk,

did you turn off your amp at all during the tuning process in order to see just the freq curve of your sub? i didn't realize my sub still played a lot of material above my 80hz crossover that i had set for my mains.

If I could put in my two cents? I tried what jonaro wanted to do by muting my reciever and you get no test tone, so you can't see any freq response. and Gonk what I meant to say in my last post.I hope I wasn't a bother with all the questions. thanks

You weren't a bother, loopy. Q&A is one of the reasons that we all gather here, after all.

Shutting off my amps is not an easy process (the M200's are under the TV, and probably the only way to turn them off short of hiring a leprechaun to crawl into the cabinet would be to unplug the amps at the power conditioner), so it didn't even occur to me to try it. I did mute the SMS-1 some to see how the mains faired without the sub, but that's about it.

you can't mute your receiver as that is the source of your test tone. i turned off my amp which sends the test tone to my mains. i'm not sure if it is providing any useful info to me. i've been messing with the slope which came as a default of 24/db and i honestly can't see any change in my freq curve.

what i found handy is to overlay my 990 menu with the sms curve so that i can see changes made thru my 990 immediately on my freq curve of the sms. realized that a 60hz crossover resulted in a smoother freq curve sans the big dips i was getting at a 80hz crossover.

another big help is to write down where you put your slides and their settings as it makes it easy to compare various tweaks you might have done.

a cool feature that isn't included, but i wish was, would be the ability to compare freq curves to determine which one ultimately was better. you can make so many small tweaks that it is easy to lose track of what you had in terms of a freq curve and what you now have. hope that makes sense.

Good point. One trick to do what you are thinking of would be to experiment with adjusting each preset's EQ separately and flip between them to compare - then write down the settings that work best and apply them to the "setup" preset.

good point gonk. lots of practice till my new sub comes!

also I tried setting the crossover in the sms to 60 and left my reciever at 80 seemto smooth things out for me, I was worried about noise or low output because that is what it says in the manual I also adjusted the phase on the subs I have a volume type phase, I set one to 180 and one to about 40 and it brought up some of the dips boy there so much you can do be it bring up the volume, change crossovers etc. having lots of fun playing though.

loopy,

you are cascading your crossovers. use either your pre-pro or the sms but not both.

can you use it at the same crossover, I put it at 80 which is what my reciever is at and used the 24DB octave slope and it smoothes my response out or is this not the right thing to do,I have just been doing different things to try get the respone flat,the way it's set up I only have to boost or cut with the eq 1 to 1.5 db on the slides from 20 to100 But if you think what i'm doing is wrong I will change it again thanks guys

Two crossovers at the same point will essentially create a dip in response around that point - the two crossovers' slopes will basically combine, exaggerating the effect of the slope. It is something that is generally recommended against, but with the SMS-1's ability to show you exactly what is happening I'm a little less leery of the idea (after all, you can see the flat response, so there's no dip created).

The one problem I see with using the SMS-1's crossover at all when also using a receiver's crossover is that any LFE soundtrack data (the information contained only in the .1 channel) above 80Hz (or wherever the SMS-1's crossover is set) will be lost. The ideal approach would be to turn off the SMS-1's crossover since your receiver already takes care of bass management. If there is a peak at 80Hz afterward, you can try to flatten it out with the EQ. You might also play with your receiver's crossover point if it allows it. Jongaro did this - he moved his crossover from 80Hz to 60Hz - and was able to get a flatter response, but not all receivers have enough bass management flexibility to make this a convenient option.

yes I'll try that, I 'm still playing around with it to see what things do but a big difference came with just adjusting the phase on the two subs.

Tried something new this morning, set my fronts to small, and bass out to just sub and crossover to 60 and and sub distance in reciever from the default setting of 10 feet to 8 feet made a big difference just wanted to let people know so they have other thing to try and thanks so much for your help guys also shut off crossover in sms I got so excited that i wasn't thinking

I am going to use this unit on a stereo system. My plan is to remove my ICBM (which happens to be set at 80hz anyway) with this unit and EQ only my IB sub.

As I understand it there are a set of inputs on the SMS that permit a full frequency stereo analog input (such as would be output from a stereo pre-amp) and there are also two sets of analog outputs. One set passes the full bandwidth and the other passes only the signal above the fixed 80hx crossover point.

So far, thats cool.

But...because I run an IB sub, I have NO gain control. It runs wide open off of two M2200's. There is also NO subwoofer out on the pre-amp so I have no gain control there either. The only sub gain will be the SMS (as the ICBM is the only sub gain now)

Now...what I need to know is this:

When I use the gain on my pre-amp (the overall system gain) will it also boost the sub gain accordingly like it now does with the ICBM or do the sub outs on the SMS need to be adjusted separately? (this sounds stupid but I have seen this type of set up before).

My hope is that once adjusted, the SMS will increase or decrease the sub volume along with the input gain, AND that if I wish, I can boost or cut JUST the sub level (via remote) to taste for thin recordings or overly fat ones.

Anyone using one of these SMS's for a stereo?

Mike

I think I follow your question. Increasing the gain on the pre-amp will affect the volume of the signal coming into the SMS-1, and that increase will appear in the SMS-1 output as well. It will do exactly what you hope it does - track the gain/volume of the main system and boost or cut the subwoofer independently as desired. Oh, and the default volume for the SMS-1 is remembered as one of the settings, so if you change it and want to go back to your default you can simply hit "RESET" on the remote and it will put you back where you calibrated to. It will also return to the default volume when turned off and back on (although I've been leaving mine on all the time).