Line out to proamp options

[Brodon]

Hey Team,

I know this is a topic that has been covered quite a bit, but in my searching I have not found the exact info I am looking for. I just finished building a custom subwoofer setup using two of the new Stereo Integrity SQL15 drivers and a Crown XLS 1502 being run through a pretty low end Denon receiver. I am running from rca out on the receiver to the rca in on the crown and I am running one sub for each channel on the amp. The subs are dual 2 ohm voice coil, and I am presenting a 4ohm load to each channel. The crown is set to the higher sensitivity for the input (.775v I think is what its labeled as). That said, I have had to turn the LFE level up to its highest possible setting on the Denon (+12) and I see only one or two leds lighting up on the front signal level indicator on the Crown even at high volumes. I get decent output to the sub, but still far lacking compared to possible output from my previous Velodyne sub which was smaller and about 1/4 of the power of this setup.

I have seen people using the ART cleanbox and similar devices, but have seen that a lot of them are using them to convert rca to XLR. Do these devices also boost signal from RCA in to RCA out as well? Also, what is the consensus on the best option for that these days? Heard the ART starts to reduce output below 30Hz for example. Samson S convert seemed well regarded, but no longer available.

Is there a unit that will achieve the goal of boosting signal but also has built in DSP functions? I know this topic has been tread multiple times, but looking for the most up to date info. Thanks in advance for any helpful responses.

[billfitzmaurice]

Your receiver output is consumer level, -10dBv, the amp input is pro-level, +4dBu. In addition the pro amp is looking for a balanced signal for maximum sensitivity. You need something that will take that unbalanced -10dBv signal and boost it to +4dBu balanced. I can't recommend anything from personal experience.

[Brodon]

Hi Bill, thank you for the response. That is definitely what most people typically do with proamps that only have the XLR type inputs a la Behringer, etc. Since the crown offers RCA level input (That is what I am currently using and getting some volume, but not as much as I know the amp is capable of), I was wondering if there is a good alternative that anyone has tried? I have been searching more and found this little signal booster from Home Theater Direct that seems like it could work. I do not know if this would cause any kind of signal degradation though. https://www.htd.com/LGB-1

[fpitas]

That Crown has selectable input sensitivity, first make sure you're switched to the most sensitive setting: https://www.crownaudio.com/en/products/xls-1502

[devnull]

Check that the speak-on is wired correctly
Check that the amp is in the correct mode Check that you have no filters set up
Check that the sensitivity is set correctly

[Brodon]

I definitely have it set to the higher sensitivity setting. Only filter right now is a high pass filter at 80hz (same results without it). Not using speakon, this unit has regular speaker wire connections that I am using. Mode seems correct as well. I had a little issue with a hurricane nut that pulled out of the MDF, so I have to repair the baffle and rotate the driver in some new holes, but when it is back together I will test again and play with the settings on the denon and the crown one more time. I ordered that line amplifier. I think it is close enough with my current settings that just a little boost will get me what I need/want

[johnny5jz]

If you can download a 50 hz sinewave tone, you could measure the output of the sub out. Most receivers have a specified output of around 1 volt. If you have a multimeter you can play the tone, turn up the volume, and measure the output. That will verify if you have something wrong with your receiver.

[Paul O]

Only filter right now is a high pass filter at 80hz

You mean low pass right? What filters are set in the Denon?

[Brodon]

No meant high pass. The denon has the crossover point on the mains at 80hz to block low frequencies. I was only referring to the LFE channel. The crown has a high pass to block anything above 80hz on the sub. I can change that point, but it was just selected during initial testing since it was the same point of transition as the speakers.

[Brodon]

Sorry to bump this, but the forum would not let me edit the most recent post. I just wanted to follow up in case anyone else has a similar question and stumbles across this thread. The little box I linked above from HTD solved my problem perfectly. Now i get plenty of signal running to the crown amp. As a result, I am getting a little noise when the room is silent and nothing is playing through the speakers, but it is a very low hum (which I got when the gain was up higher to compensate previously as well). Would be imperceptible with any background noise. I am very happy with the output at this point, but I want to see what these subs are capable of, as I can tell I am not fully driving them. The power rating is 1000watts RMS on the sub and the crown is "only" putting 775 per channel in 2ohm stereo mode. So, I decided to order a crown 2502 to see if there is a noticeable enough difference to justify the extra money. If not, I will return it. If I decided to keep the 2502 (Which I think I probably will), then I will sell the 1502 to recoup some of the expense.