Axiom Home Page Forums General Discussion Technical Questions Amount of gain on EP500 volume control

When calibrating the EP500 sub, how much gain (in dB) should I expect when moving from minimum gain to maximum gain on the volume control/knob of the amp?

I currently have my sub calibrated to 75 dB (to match the left front speaker) and the volume control/knob is at approximately 7:00 with the receiver's trim at -10 dB (left front speaker is at -3 dB). How much of an increase (in dB) should I experience if I increase the sub's amplifer gain control to its maximum setting while keeping the receiver's volume/settings consistent?

Thanks in advance!

Is your home fully paid off, and/or do you have a line of credit to cover the repairs you'll have to make?

Bryan, first a little bit of terminology/technology. The volume control on an amplifier, including a sub amplifier, isn't actually a gain control. Amplifiers provide the full designed gain of the incoming voltage whenever they're on and receiving some input. This is typically about 25-30dB of voltage gain, which is an increase in the voltage of a bit less than 30 times. What the volume control does doesn't change the amount of gain, but either allows all the incoming voltage through to be amplified(at its maximum setting)or reduces the incoming voltage to practically zero(at its minimum setting).

Now, at the minimum setting the sound level would be essentially zero, while at the maximum setting when a strong bass signal was input the sub might play at well over 100dB if the sub amplifier was capable of the required output and the sub driver could handle it(neither may be possible; just because there's room left on the volume control doesn't guarantee results). Maybe 40dB over the 75dB figure might be possible with a good sub.

I am not quite sure I understand your post. Are you saying you have your EP500 gain contol set to max while the gain on the receiver for the subwoofer is set -10?

Are you using an auto setup or an SPL meter when you calibrated?

I would set the subwoofer gain to the half point (maybe even less) and set the receiver trim to -4 to start and then gradually increase the trim on the receiver to level match the subwoofer using an SPL meter.

If using an auto setup, I would set the sub gain to half and run it mulitple times to see what kind of results you get.

No, he said he has the volume(gain) knob at 7 o'clock and the receiver at -10db level. I think most of us run our 500 and 600's knob pretty low, around 6-7 o'clock, 2however, I'm able to have my receiver closer to 0dB (-2dB) must be because of my larger room.

It is unlikely he will be able to start at the midpoint on the EP subs, historically that brings your drywall down.

Hi,

As Dr.House has pointed out, you should increase the AV receiver sub level trim towards the -2 or 0-dB mark, so that the subwoofer gets enough voltage from the AV receiver to ensure that the auto-on signal-sensing function will kick in and activate the subwoofer, especially with low-level music CDs.

You certainly never want to run the sub's own volume control at maximum. Find a kind of happy medium between the sub's volume control and the AV receiver's sub level adjustment.

Regards,
Alan

As sirquack mentioned, the EP500 volume control is at the 7:00pm setting while the Outlaw 990 receiver's subwoofer channel setting is at -10db (compared to -3dB for the front left main channel).

I am a little concerned that I've trimmed the receiver's setting to -10dB as per Alan's post - not getting enough voltage to ensure the subwoofer's amp is turned on. However, if I set the receiver's setting any higher, I'll need to turn the EP500's volume control closer to the minimum volume setting (perhaps 6:00pm to 4:00pm).

My original question was how much variance (in dB) I should expect between say 6:00pm and 12:00 on the EP500 volume control? For example, if 7:00pm on the EP500 at -10 dB on the receiver yields 75 dB (when played at reference), what should 12:00 on the EP500 yield?

Perhaps I haven't explained this well enough. I ask because I had to send back a faulty EP500 amplifier due to a faulty volume control. I'm simply wondering how much variance should exist between minimum and maximum settings on the EP500 volume control.

Thanks!

I can’t give exact number but I can offer some perspective. When I first set up my EP500 I misread the documentation and the sub volume at 9 o’clock with the receiver at 0dB and played a test tone. Before I could hit the mute button the windows, dishes in the kitchen and something inside the TV started rattling violently. To get it down to 75dB with the receiver set at 0dB I turned the subwoofer volume down to between 6:30 and 6:00 o’clock. I can’t imagine what it would have done had I set it to 12:00.

Turning it down won't hurt anything.

Bryan, the concern that you describe shouldn't be a major one. If you want the sub trim on the receiver to be significantly higher than -10(although it's possible that the 990's sub output is higher than most)so that you're confident that enough voltage is being fed in to keep the sub amp "awake", turn the volume control on the sub even lower than 7:00. There's no disadvantage to this, as it just cuts the part of the incoming voltage that actually winds up being amplified in the sub amplifier down farther.

Makes me wonder how complicated it is to set up a HT system. My nephew with a Bose system just plugged it in and turned it on.

No highs, No lows, must be BOSE.

Iceman, another option would be to pick 78dB as your target, something a little higher. I used to have the same problem on my 500 and 1st 600 amp as you describe. Also, it won't hurt to put the sub on 6 o'clock...that way you should be able to bump up the outlaw a little more....

I wonder what percentage of your posts are that line, Randy.

Bryan, I will guess you are wondering about the overall output of the sub's amp and how much SPL increase there is going from minimum to maximum, trying to see if this amp is up to specs or not. I don't know the answer, as yours was my first and only EP500 experience.

Like the others have said, turn up the receiver output and drop the volume on the sub's amp, no problems this way. I have my sub's volume control near minimum and the receiver output at -5.

My 500 has been and still is the hardest part of my home theater to set up. After a couple phone calls to Axiom last week and tweaking the trim from half to full to get more bottom end which I feel I'm extremely lacking, I'm still not happy.

I need a local Axiomite's assistance.

wheelz999,

Have you ever ran Audyssey's auto calibration on your Denon?

You could basically do the same thing with your new set up but you won't get the maximum benefit (sound) of having it.

For the amount of time you've spent scrutinizing your decision and concerning how much money you're putting into this. I would hope you would have the interest and desire to want to learn to set it up correctly and maximize the potential. It really isn't that hard, but yes, there is a lot of new information and terms to learn. Making sure to read through the manuals, hit the net and ask question will make the set up that much easier.

Don't worry Bob you're in good hands here and you'll be very happy you didn't buy an over priced plug an play system.

Yes I have ran it several times and I wasn't very happy at all with the results. Honestly, this sub does sound different than when I first purchased it, but I don't know if that has to do with all the renovations and the room dimensions drastically changing.

Thanks for all the replies and advice. It helps to hear others have had similar issues.

I'm going to play some more with it today. I'm going to increase the 990 receiver's subwoofer output level to around -5 dB (for comparison, my front left main is at -2 dB) and drop the EP500 volume control down. I also think I'm going to calibrate the subwoofer level a little higher than 75 dB on the SPL meter. I know that the SPL meter isn't reading the actual subwoofer level at such low frequencies, such that a reading of 75 dB actually indicates a higher real SPL level. But I don't listen to things too loudly and feel that I lose the subwoofer at lower listening levels. I'll try and calibrate it to 80 dB on the SPL meter and see how that sounds.

Is there any concern setting the EP500 amp's volume level down to between 4:00 and 6:00?

BTW - I haven't played around with the Full/Half settings on the EP500 amplifier? Do these make a big difference? I might try these out as well. I might also play around with different locations for the sub but I'm somewhat limited in placement.

Thanks again!

I was told that the trim setting depends on, or a lot on your room. The issue I am having with my 500 is that I'm lacking the bottom end. This isn't really that new in the sense that I've been testing different placement hoping for different results and that I'm very limited with the amount that I'm actually able to get up and about. When I first got the 500 I was totally happy with it, lots of bottom end "boomy bass", just overall good LFE, and back then I had my trim setting to "flat". I listen to a lot of music with bass in it and am well accustomed to certain songs, now when I'm playing them I get a noticeable "thud" sound with some bass. It's improved slightly when the trim is set to full, but it just doesn't sound as it once did.

Cam, better check for stuffed animals in the port.

Who you talkin' to?

Me?

He did say Bob, don't worry we are here to help, why ya getting all excited.

Because we are never much help?

Does soft plastic and air, with a name and blonde hair constitute a stuffed animal?

wheelz999 - I'm in a similar situation as you as I don't feel that I'm quite getting the performance/response out of my 500 as I expect. My problem was that the 500's original amp had a faulty volume control and I couldn't calibrate the sub to match the same level as the other speakers. I didn't realize this to be a problem for some time, though, as I just recently had the opportunity to use an SPL meter (thanks to jakewash) to calibrate. Before that, I simply ran the 500 extremely hot and didn't realize (due to my ignorance) that my sub was playing too loudly. Now that it is properly calibrated, I don't feel it's response is "quite right". Keep in mind - I probably don't know what "right" is and that may be the problem

I'm going to keep working on it. And, much to appreciation, I'm going to lean on the expertise of jakewash to keep helping me out when I have the time.

Good luck with your tweaking.

Bryan

Whenever I calibrate our 600 with the rest of the system using the SPL meter it seems a little too weak for me so I run the sub about 3-5 db's hotter than the other speakers, and then sometimes will bump it up or down a little depending on the material being played.

Even after exacting calibration with the SPL meter you may still want to tweak the system for your ears, after all that's what really matters.

That's one of the benefits of the BFD. I like running the sub about +6db hot on the extreme low end, with a house curve bringing it slowly down to +0db. The "boominess" seems to hit me around the 60Hz range, and by that time I'm down to +0db, while still retaining the boost at the extreme low end.

Yes sir.

Issues with bass could have to do with a lot of different things.

Ricks comment about running the sub hot seems to be quite common and probably has to do with our reduced sensitivity to sound the lower we get in frequency. [Most] Everyone seems to run their sub hot.

Bass seems to be the most affected part of the spectrum in smaller rooms as well. Small rooms seem to bunch up room modes so that you get pronounced peaks or nulls, so that missing bass could well really be missing without it being the subs fault.

Room modes can also be beneficial. My first mode for room length is at around 24Hz and is probably the reason I am getting extension down to 21Hz with my EP350.

It can also be that whatever sub/speakers you had in the past had a boost at one frequency that you had gotten used to, so when you get a better sub like the EP500 that has a flat frequency response, you feel like you are missing something.

Last, but not least, it can be the position of the sub.

So, there are lots of variables in the equation and it can take a while to sort things out.

At this point there are three things you can do: tweek until you get tired of it and then call it a day, buy an EP800 , measure whats going on in your room to see whats going on.

The only way to know what is really going on in your room is to measure it either manually or with software like REW.

Here is an example of an in room measured response. If you look at the first graph you can see how there are peaks and valleys showing how my room and the position of the sub affects its response. Measuring like this can quickly tell you what is going on with your sub at various positions in your room.

Fixing some of the stuff you find while measuring can be challenging, but once you measure, at least you know what you are dealing with.

Hey Hay, (that's weird)

Yes this is a lot of money for me. Especially without having heard these speakers. Someone did offer an audition a while back but never came through. It's been weeks since I ordered. Many of my comments have been in jest. However there are times when I don't know what the heck is going on. Maybe I put a little too much weight on people's opinions.

In the beginning I heard that M80's give great detail even at low volumes. Now I hear that M80's may be to big for anything but a large room.

I heard problems with someone's setup with a 350 maybe not being enough. I have thought long and hard for a long time about upgrading to a 500. In this thread in sounds like a 500 is had to calibrate. (btw I did upgrade to a 500)

In another thread it sounds like the M60's put out plenty of bass and maybe don't need a sub. Since I'm getting M80's and they produce more bass than an M60 what am I suppose to think.

Center Channel: Go without and have a Phantom Center. M22's, VP150, M80 At times I think it's NOT me who can't make up m mind.

QS8's only problem here is the guy who wants to go back to 2.0 or 2.1

I guess my problem is that I'm a sucker for a deal. The more I buy the cheaper it is. The better I go the less chance of sending something back and paying shipping and maybe a higher cost for not getting the same discount as getting it all at once.

I was hearing about how seemlessly each Axiom component blends with each other and now I'm hearing about how complicated the calibrating is and getting comments about my "interest and desire" to get my system set up right.

Is my head spinning right now? You bet it is!

BoB/335

You seem to have spent a great deal of time and have gathered quite a bit of information before choosing your current setup. My advice is not to overthink anything at this stage. Your system should be arriving soon, correct?

Information overload. I'm glad I could contribute to your confusion.

Its all about context though. For instance, talking about the effects of a room on a sub and the challenges of figuring out what the cause and effects are (and how to deal with that) is different than integration of a sub with the mains.

Relax, wait for your stuff to ship, and listen for yourself.

For the record, I do think that the M80s are a tad big for the loo.

Don't worry Bob, it will all be good. The only problem comes when you start to tinker and calibrate too much and then it becomes a never ending quest.

You should be more than happy with everything you're getting. Take your time to just set it up, play with it, get familiar and then do a basic calibration. If you're happy take a break and enjoy it and then when you have time or interest tweak a little more.

You should be ready for the 500 and ensure all knick knacks are secured. I had one originally and it was crazy how much it put out and how much it still had left over. I ended up returning it for a couple reasons but the main one was the cost over what I got my HSU VTF3-MK2 for and how well it performed for the price difference in MY room.

Have your wife with the camera in hand to take a picture of you when your fire up the system with War of the Worlds queued up