Presonus Eris Sub8 - Odd subwoofer volume issue

[Blevee]

Greetings from a long time lurker (5+ years). Hoping you can help me resolve an issue I'm having.

I recently acquired a Presonus Eris Sub8 subwoofer to use with a couple different pairs of active speakers for a desktop setup and/or in a workout room. I'm seeing very odd unexpected functioning, so much so that I'm going to return it and either buy another or something else.

The Presonus Eris Sub8 is a front driver front ported studio monitor subwoofer with an 8 inch driver. It offers balanced TRS connectivity and unbalanced RCA connectivity with a selectable High Pass Filter (HPF) with LINE IN and LINE OUT for both balanced and unbalanced pathways.

All of my connectivity per following was via unbalanced RCA's. I have no sources with balanced connectivity to test with.

When I connect via LINE OUT of a device to the LINE IN of the Sub8 and from LINE OUT of the Sub8 to the LINE IN of a set of active speakers, there is an unexpected gain of volume with the subs' driver while it seems that no extra volume output is provided to the connected pairs of active speakers. So much so that the baffle over the sub driver rattles during some tracks and I was forced to lower the gain on the Sub8 to near -30dB.

I experienced this with my active Kanto YU2's and a set of active Fluance Ai40's. If anything, with the Sub8 I was expecting to have it set at closer to 0 dB gain with the unbalanced RCA's as with these studio subs you'll often see the balanced connectors marked +4dB and the unbalanced connectors marked -10dB (or similar). I could not get the sound level of the subwoofer driver to balance against the satellite levels at a reasonable listening level. The bass was always overpowering.

I've tested with four sources streaming music to the Sub8 + satellite active speakers.

1. the selectable L/R RCA LINE OUT of my Topping DX3 Pro+ DAC/Headphone Amp that offers variable -0 to -99 dB gain on the Line Out,
2. the headphone jack of my laptop using a 3.5mm to dual RCA adapter and
3. the RCA LINE OUT from an old SMSL M100 DAC that offers only non-variable output.
4. the built in DAC of the Kanto YU2's via LFE port

The result being that from the first 3 sources, the sub's volume is overbearingly loud and/or cannot be balanced against the volume level of the satellite speakers, either YU2's or the Ai40's. It is almost as if the sub driver is getting something like +14db fed to it internally while the LINE OUT from the Sub8 is at -30dB to the satellite actives.

However, when I connect via the built in DAC of the Kanto YU2's and then connect to the Sub8 using the LFE port of the YU2's thru a Y splitter to the LINE IN L/R RCA's of the Sub8, with nothing connected off the Sub8 LINE OUT, the system sounds really fantastic. Big, spacious, and great detail from the YU2's in servicing the mids & highs.

I had hoped to use the High Pass Filter that the SUB8 offers so this inability to use the Sub8's LINE IN thru LINE OUT is really disappointing.

I figure I have missed something very fundamental about how this type of subwoofer works, particularly what is coming out of the DAC Line Out's and the laptop headphone jack versus what the subwoofer Line In is expecting.

As I'm looking down the road at getting something like a pair of Kali Audio LP-6's or JBL 305P's (balanced) to use with this sub or maybe a pair of Klipsch The Fives (unbalanced), I would appreciate any guidance you can provide.

B

 

[AnalogSteph]

The result being that from the first 3 sources, the sub's volume is overbearingly loud and/or cannot be balanced against the volume level of the satellite speakers, either YU2's or the Ai40's.

So let me get that straight - sub input gain is already at -30 dB and volume on the satellite speakers is cranked up, and you still cannot get proper integration?

Volume control obviously has to happen on the source end.

 

[Blevee]

Both the Kanto's and Fluances were used with their volume control varied up to about 75% of max. There is obvious hiss/line noise (an issue noted in some reviews) with the Fluance's over 75%.

The Fluance's normally by themselves are never over about 70% in my workout area as I find them too loud. I've measured about 90+ dB cranked in that space at 10 feet away.

I could not get either in balance against the Sub8 using the LINE IN / LINE OUT pathway of the Sub8. The Sub8 drive always sounded over driven in relation to the output from the satellites except when it was at somewhere between -27db to -30dB (a very small movement of its Gain knob) and then it seemed abnormally muted. Move the Gain control just a bit higher and the state of sounding over driven returns.

I also tried lowering the variable output of the LINE OUT of the Topping DX3 Pro+. It ranges from 0 to -99. Connecting the DX3 Pro+ directly to the LINE IN of the satellites did not induce any sense of the active pair being over driven, even at 0 output. Yet that same level thru the Sub8 LINE IN / LINE OUT pathway resulted in what seems to be the woofer driver being over driven.

If I went digital to the Kanto's DAC and then LFE to the LINE IN of the Sub8 and NOT using the LINE OUT of the Sub8, it is a very pleasing sonic experience and easily adjustable.

It is just odd to me that the Sub8 driver would seem so over driven and yet the satellites connected from its' LINE OUT are not demonstrating any sense of being over driven.

.

 

[Berwhale]

FWIW, I'm using the Sub8 in-line between my Topping EX5 and iLoud MTMs using the balanced connections. I have no issues with the volume from the Sub8.

I set the reference volume for the Sub8 using a UMIK-1/REW following the instructions in the Presonus manual. I have the gain turned down a little as I found it a tad too loud - input gain is set to -20dB (LPF is set to 80Hz, HPF is Off).

The 'volume' on the iLoud's is set around 1 o'clock (which is maybe 60%) - LF Extension is set to 80Hz on the iLouds and sensitivity is set to +4dBu.