D.I.Y Sonosub not working properly (AMP and receiver issues)

[ReZeN]

okay i built a sonosub With an RLP D2 15" driver it is wired to have a 4 ohm load, and I bought a Crown XTI 1000 from Dougie. I own a Denon AVR-987. The sub works but the amp bearly pushes the sub.... the only way the sub works properly is if i raise the gain on the amp all the way... and the gain on the receiver for the Sub woofer all the way up to like 12 db..... it hits hard right their... but my question is what could be the issue.... and how can i resolve it thanks

[ThomasW]

Sounds like a line level shifing device is in order.....

http://www.artproaudio.com/products.asp?type=90&cat=13&id=77

[ReZeN]

ThomasW,

when i was playing gears of war today i noticed that the sub would cut out.... i would have to turn off the amp then turn it back on.... then the sub would work once again... do you still think the device you suggested to buy will fix the prblem of the amp not sending signal to sub after it is on for a while......

also i was wondering if using the sub with the amp gain and receiver SW channel gain to the max can mess up the receiver or amp.... thanks for the help

[kevmurray]

Where is the sub positioned in the room? What are the dimensions of the room?

Kevin

[ThomasW]

do you still think the device you suggested to buy will fix the prblem of the amp not sending signal to sub after it is on for a while......

The device simply raises the drive voltage level going to the amp.

From the Crown website the amp takes 1.4 volts to drive it to full output. I don't know what the output drive voltage is of the Denon sub-out circuit (see the specs in your owners manual for this info)

I'm not familar with the specifics of the amp other than it has a ton of DSP protection, EQ and other functions. It's possible these are having an effect.

[Dennis H]

AFAIK, Denons have plenty of output voltage to drive a pro amp. People have had problems in the past with defective adapters between RCA cables and pro amp inputs. Got an ohm meter to check the cable/adapter?

[ReZeN]

i have a volt /ohm meter how can i check if the cable is good?i dont want to spend 60 dollars and its not the problem



Im looking at the SPECS in the Manual

it doesnt say anything about the voltage on the pre outs onlything i can maybe see is....

it says Rated Output 1.2V in anolog mode


Rated Output in digital is
2V at 0db playback.....

i hope this helps

[ThomasW]

Set the meter to measure ohms and check to see if the cable has an open circuit.

1.2V is more than enough output to drive the amp pretty loud.

You should review the Crown owner's manual to make sure there aren't some settings causing the problem.

[ReZeN]

i took the readings on the cable today... i got readings when Ohms was set to 200.... but i notcied i only got readings from one prong on the xlr cable... if i touched prong 2 and rca with Volt Meter i would get nothing prong 3 and rca got nothing prong 1 and rca got a reading of .04....


thanks for the help

[ReZeN]

alright guys i had my dads friend check the cable and he said everything is good he checked with a voltmeter... so the cable isnt the problem

[ThomasW]

If you have a iPod, Walkman, Discman, whatever, run the headphone out into the Crown. If you don't get any sound from the sub either the amp is bad, or there are internal settings for the amp that are causing the problem.

Beyond this I have no clue other than taking the amp into a service center....

[geoffstgermaine]

I'm running an XTI 2000 with a Onkyo TX-SR674 and I've had no problems with levels. I was even running a pair of SS RL-p15s before. I am not sure what the output voltage of the Onkyo is.

[Adam321]

The XTI-1000 has built in crossovers and can be configured for sub duty. However, if you are using the sub output on your Denon and have the crossover on it set, then you are using the filters in parrallel and will have reduced output. If you are using the Denon crossover, you should be running the Crown full bandwidth with no low pass crossover. You can use a high pass so nothing below say 10 hz goes to the sub, as an example, if the Crown has a high pass for that low a frequency. Of course this depends on the tuning frequency of your sub. Let one or the other do the crossover not both.

[Hdale85]

The crowns crossovers are not being used. I helped him make sure of that.

[exojam]

What is the "channel level" for the sub set for in the Denon? I have a Denon 3803 and have it set to +1db with the same Crown as you and it works fine. I have the Crown set to about the 1 or 2 o'clock position. You can also download the System Architect from the Harman Pro website and see what the input level is showing on the Crown.

[ReZeN]

excojam do you have one of the presets selected on the amp, and if so which one... i dont have windows anymore so does the program work with OS X?

[exojam]

I did have the BRG SUBS preset but made a custom one. I am not sure what OS can be used but I would look on their website and it should say.

[ReZeN]

right now i have the channel set from the dennon at +12 db... and what do you exactly mean by the 1 o'clock and 2 o'clock position... i also checked the website for System Architect and it only support Windows XP SP 2 .... also do you have aim because i think the filter in the amp is what is giving the sub such a low output.... and i would like to use the same settings as you to see if it works.... thanks

[Hdale85]

The last time I helped you with System Architect we set it to default where there were no filters enabled.

[exojam]

I was referring to the "level" control for channel one (the rotary dial). I am not sure what you mean about "aim". What preset do you show on the display of the amp? When you play a test tone on from the Denon do you get a signal led on the Crown?

[Dennis H]

Ithe only way the sub works properly is if i raise the gain on the amp all the way... and the gain on the receiver for the Sub woofer all the way up to like 12 db..... it hits hard right their... but my question is what could be the issue.... and how can i resolve it thanks

Errrr, what "issue" are you trying to fix? Turn the amp up all the way (standard mating pro gear to consumer gear) and set the receiver to whatever it takes to get the right SPL. Have you calibrated with an SPL meter? Maybe you just like the bass way too hot.

[ReZeN]

Dennis H,

when i have gain on amp like mid way and gain on receiver at +1db you can bearly even hear the sub....... and plus the signal cuts out on the sub... like i'll be watching a movie and the sub wont work then all a sudden the sub works again... after i turn the amp off then back on... so i dunno what it could be

[Dennis H]

when i have gain on amp like mid way and gain on receiver at +1db you can bearly even hear the sub....... and plus the signal cuts out on the sub... like i'll be watching a movie and the sub wont work then all a sudden the sub works again... after i turn the amp off then back on... so i dunno what it could be

Turn the amp's volume controls up all the way. Use the receiver's test tones and an SPL meter to set the receiver's sub level. Running at extremely low levels like you describe, I suspect the amp's AD converter (analog to digital for the DSP functions) isn't sensing a signal so it mutes the input. So turn it up!

[Hdale85]

Thats what I'm thinking as well. He had it turned up all the way before. The signal from the receiver is just too low. Also feeding an unbalanced signal to a balanced input might have something to do with it. Regardless I'm pretty posative he has everything setup right it's just a lower end receiver and the pro amp needs a pretty high input.

[exojam]

If he has the sub channel level set to +12db on the Denon, I don't think he needs to max the level control on the amp. I have an older Denon and only have my level set +1 or 1.5 on the sub and the level on the Crown at the 1 or 2 o'clock position and it works fine. The part that is making me think it is working correctly is when he said this "and plus the signal cuts out on the sub... like i'll be watching a movie and the sub wont work then all a sudden the sub works again". This seems to tell me the amp is getting a signal and playing when it is supposed to and not getting a signal and not playing when it is not supposed to. I watch my "signal" led on the Crown go on and off all time during movies and music. I do agree with Dennis that the easiest thing to do is calibrate with an SPL meter.

[Hdale85]

Well an older Denon and a low end Denon are 2 different things. I don't know I really think the Clean Box will fix his issues.

[Dennis H]

If he has the sub channel level set to +12db on the Denon, I don't think he needs to max the level control on the amp.

In the post I was replying too, he said he had problems with the Denon set at +1 and the amp's level controls set midway, typically -10dB on a pro amp but I don't see any dB markings on the XTi. You need to start with the level controls all the way up on a pro amp to match the sensitivity of a consumer amp. Then, if it's too loud, you can turn the level controls down to improve S/N ratio. There are no level controls on a consumer amp and the controls on a pro amp are just pots to knock down input signals as high as 10V from a pro mixer -- way higher than any receiver will put out.

[ReZeN]

Hey guys,

I took off the crossover on the amp and noticed it helped the sub some, but i still lose signal to the sub when running the channel level setup on the Denon receiver. It sends a low freq to the sub while testing it, so after running these tests I started to play Halo 3 everything is working great, then i noticed the sub isn't hitting when its supposed to, so i went back to the channel level setup and the sub wasn't working. I let it send signal after a while and the sub was cutting in and out and the sound was really distorted. Once i turn the amp off and back on the sub begins to work again. Is the clean box really the answer?

[Hdale85]

I think it is. I mean it just sounds like its a low signal level to me. The pro amp can't lock the signal there for it loses it. But it works somewhat when there is a lot of action going on or something. I really doubt that anything but the Clean Box is going to help you.

[exojam]

You may have to go that way but I would call Denon and ask what the output voltage of that receiver is and if you can find a voltmeter that will go down to 1 volt rms you can measure the output to see what you have. The only reason I say 1 volt is the amp only needs 1.4 to run to spec.

[Hdale85]

I believe he said it's 1.2v But maybe that was a guess.

[ThomasW]

I believe he said it's 1.2v But maybe that was a guess.

That's from the owner's manual, I just looked it up online...

[Hdale85]

Oh, well it could be inaccurate? I don't know. Maybe thats max output?

[exojam]

Dang, I looked all over that manual and did not see it. If it's 1.2 that should not be an issue than.

[ThomasW]

In the specs section, analog pre outputs, it says 1.2V

http://www.usa.denon.com/AVR987Lit.pdf

[ReZeN]

Thomas W,

So what do you think about the clean box fixing the problem, i have an iPod i am going to try what you said about hooking it up to the amp later on today. I am also going to contact crown to see what settings the amp should be on to be running a sub.

[exojam]

rez,

Don't yell, I just have to ask. Do you have the manual for the amp? If not you can download it from there website and it covers everything in it. Also, another silly question, you do have the sub wired to the amp in the bridged wire posts correct?

[Hdale85]

ReZ, You have all the crossover stuff turned off correct? If so then you have it setup correctly. Your reciever is doing the LFE and everything for your sub because you have it connected to the sub output.

[exojam]

Doug,

If he has the crossover turned off on the Crown it sounds like he would have had to create a custom setting and I thought he did not have a pc to connect to the amp and I thought that was the only way to make custom setting. If he sets the preset of "brg subs" it will set a crossover at 90 and if on the Denon he sets it to 80, I would not see an issue would you?

[Hdale85]

No but if he has the crossover on the Denon set to 80 that should be fine as well with the crossover turned off on the Crown. Just means the crown is not doing anything to the signal so it gets what the reciever sends to it. He had a PC it was just really slow. It took him like 10 min to load up the program and I think his PC is dead now. He just got a Mac Mini.

[exojam]

So than a custom program was created for the Crown, correct? I would like to know what icons are displayed on the Crown.

[Hdale85]

No everything was just turned off as far as filters and crossovers. It was locked when he got it so he had to unlock it with the program.

[ReZeN]

i have the pre-set to sub synth and i have the sub hooked up to channel 1. should i try using the BRG Subs... hook up to BRG in the binding posts of the amp and set the crossover at 80 hz on the receiver>?

[exojam]

What can your sub handle? I just don’t have time right now to go look at it but I am pushing a TC2000 15" Sonosub and I using the “bridge subs” and actually bridging the amp. With the way you are describing your hook up, the most you are putting out at max is 500 watts. If it was me, I would unlock the Crown change to bridge subs, rewire on the back of it to the bridge posts, drop your sub level in the Denon to zero to start with, put the channel one level around 1-2 o’clock and see what you get.

[ReZeN]

Hey guys,

I think i may have fixed the issue. I went to the channel 2 on the binding posts then moved the XLR cable to channel two. I edited the pre-set SUB SYNTH like this. For Y i have setting Ch1 + Ch 2, X OV is off, EQ is OUT, No delay, Limit is off, Bridge is On, i dont know if i should set to stereo tho... It seems that i am not losing signal anymore. going to check my bass with an SPL meter as suggested too.