Author Topic: Anemic subwoofer  (Read 239 times)

Offline MacGeek

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Anemic subwoofer
« on: December 30, 2018, 11:31:28 PM »
Happy New year all- I am trying to set up a temporary satellite sub system until I get my remodel finished and the big rig running.  I was running a pair of B & O S-80.2s until the woofer foams crapped the bed. They were in this house when I bought it and I was impressed with their performance until the surrounds tore ( I like life like SPLs).  In their place, I have a pair of Def Tech studio 350s paired with a Def Tech SuperCube III sub.

I am disappointed in the low frequency performance of the system with the sub, versus with-out it (the B & O's blow them away).  I am hearing very little difference with the sub in the system.  I am new to integrating subs, having historically owned full range systems, and understand it can be a challenge, but it seems to me that if the sub is not integrated well, I should be able to hear either too much or two little bass; I only get too little.

My temporary system is a minimalist approach, with no preamp.  A CD player with DAC has a volume control, as does my tuner.  Both run through a switch box to change sources, then straight to the amp.  I am using the high level speakers outs from the amp into the sub and then the high level outs to the satellites.  I have disconnected the satellites and confirmed the sub does work and seems to dig plenty deep.

I have the sub volume set to it's maximum, phase at zero (the sub and satellites are in about the same plane and distance to my chair) and have tried the x-over at several points between 40 and 150 hz.  The sub is placed in a corner and I have moved it around with no or little change in performance.

The system otherwise plays as it should, the sound stage is decent and the low frequency performance is what one would expect from a six inch two-way system. It's as if the satellites were of considerably greater sensitivity than the sub, but the system is all one manufacturer of the same vintage.

One possible option I have not tried is to split, via a "Y" connector, the output of the CD/DAC and run a low level signal directly to the sub and separately to the amp, which has variable input gain adjustments allowing me to reduce the input signal to it.  However, I am trying to avoid digging through my unpacked boxes to look for my cables and it seems I should be able to get sufficient bass the way I currently have things set-up.  By the way, I have reread the subs manual and verified all connections are correct and everything is in phase.

Hopefully someone will have an idea or two to share.

Moving sucks about as much as remodeling.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Tandberg 10X

Offline OldiesButGoodies

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Re: Anemic subwoofer
« Reply #1 on: December 31, 2018, 12:57:46 AM »
Happy New year all- I am trying to set up a temporary satellite sub system until I get my remodel finished and the big rig running.  I was running a pair of B & O S-80.2s until the woofer foams crapped the bed. They were in this house when I bought it and I was impressed with their performance until the surrounds tore ( I like life like SPLs).  In their place, I have a pair of Def Tech studio 350s paired with a Def Tech SuperCube III sub.

I am disappointed in the low frequency performance of the system with the sub, versus with-out it (the B & O's blow them away).  I am hearing very little difference with the sub in the system.  I am new to integrating subs, having historically owned full range systems, and understand it can be a challenge, but it seems to me that if the sub is not integrated well, I should be able to hear either too much or two little bass; I only get too little.

My temporary system is a minimalist approach, with no preamp.  A CD player with DAC has a volume control, as does my tuner.  Both run through a switch box to change sources, then straight to the amp.  I am using the high level speakers outs from the amp into the sub and then the high level outs to the satellites.  I have disconnected the satellites and confirmed the sub does work and seems to dig plenty deep.

I have the sub volume set to it's maximum, phase at zero (the sub and satellites are in about the same plane and distance to my chair) and have tried the x-over at several points between 40 and 150 hz.  The sub is placed in a corner and I have moved it around with no or little change in performance.

The system otherwise plays as it should, the sound stage is decent and the low frequency performance is what one would expect from a six inch two-way system. It's as if the satellites were of considerably greater sensitivity than the sub, but the system is all one manufacturer of the same vintage.

One possible option I have not tried is to split, via a "Y" connector, the output of the CD/DAC and run a low level signal directly to the sub and separately to the amp, which has variable input gain adjustments allowing me to reduce the input signal to it.  However, I am trying to avoid digging through my unpacked boxes to look for my cables and it seems I should be able to get sufficient bass the way I currently have things set-up.  By the way, I have reread the subs manual and verified all connections are correct and everything is in phase.

Hopefully someone will have an idea or two to share.

Moving sucks about as much as remodeling.

Questions: 
  • You liked how the B&Os sounded in the same position that you have the DefTech subsat system now?  (so the room does not have a crazy null at that position)
  • Have you tried slowly adjusting phase in the sub,  aiming to peak bass response at the listening position?
  • Have you done a subwoofer crawl?  (google that or ask for details)

Pepe

Spkr: Harbeth 30.1 on Sound Anchor stands
Pre: Rogue 99 Super Magnum
Power:  Rogue Stereo 90 Super Magnum
Phono: VPI Aries 1,  Denon 103R
CD: Oppo 203
Sub: Rhythmik FV15HP

Offline MacGeek

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Re: Anemic subwoofer
« Reply #2 on: December 31, 2018, 08:19:25 AM »
Pepe- Thanks for the tips.  The satellite position is about the same as with the B & O's.  I have only incremental room to reposition them, but can try them closer or further from the rear wall.  I have adjusted the phase setting, but not slowly (yet).  I have not tried the crawl, but the sub is positioned in a fashion consistent with the instructions recommended in the manual.  Finding and using my pink noise generator and measuring gear may be tough, considering the remodeling project and the shape my rom is in

The low frequency performance of the sub is actually not bad, except for the level.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Tandberg 10X

Offline Jim Pittsburgh

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Re: Anemic subwoofer
« Reply #3 on: December 31, 2018, 08:53:17 AM »
Reading through your info, I was a little taken back by the statement that you have the sub volume at max. Have never seen that necessary on any system I've heard or owned. Also didn't see where you have the transition set on the sub.... max htz before it transitions to the satellites. Very sincerely think there is something wrong with the sub amp, unless you have the transition point set at the absolute minimum (lowest htz on the dial) . That would /could explain why it isn't showing itself very much.
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Offline Kingman

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Re: Anemic subwoofer
« Reply #4 on: December 31, 2018, 11:05:23 AM »
Quote
I am using the high level speakers outs from the amp into the sub and then the high level outs to the satellites.  I have disconnected the satellites and confirmed the sub does work and seems to dig plenty deep.
...This doesn't sound right? Without the main speakers the sub has plenty of bass. Something's wrong in the connections IMHO.
IN REALITY IT ONLY MATTERS WHAT IT SOUNDS LIKE TO YOU!!!!!

Offline Sir Thrift-a-Lot

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Re: Anemic subwoofer
« Reply #5 on: December 31, 2018, 12:42:52 PM »
Reading through your info, I was a little taken back by the statement that you have the sub volume at max. Have never seen that necessary on any system I've heard or owned. Also didn't see where you have the transition set on the sub.... max htz before it transitions to the satellites. Very sincerely think there is something wrong with the sub amp, unless you have the transition point set at the absolute minimum (lowest htz on the dial) . That would /could explain why it isn't showing itself very much.

When using speaker level in and out, does the Hz knob even do anything?   I think the integrated passive x-over is likely at a fixed point.   My best guess is that the sensitivity on the satellites is much higher than on the sub.   

I also considered a polarity issue from the amp to the sub, but I don't think it would play nicely without the satellites if that were the case.   Maybe a polarity issue to one of the satellites?
« Last Edit: December 31, 2018, 12:45:04 PM by Sir Thrift-a-Lot »

Offline Sir Thrift-a-Lot

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Re: Anemic subwoofer
« Reply #6 on: December 31, 2018, 12:45:53 PM »
Or maybe the level pot is dirty.

Offline scorpio333

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Re: Anemic subwoofer
« Reply #7 on: December 31, 2018, 01:00:35 PM »
Ive been trying to find a good spot for a tiny Mirage sub in my 2 channel system. For my room, I may just need a second sub to balance things out. The crawl method works, but the sub was out in the middle of the floor in a footpath.

I've found that running leads from amp to line level on the sub and then leads from amp to speakers. NOT using line out on the sub to other speakers. It works better for me.

You could try to get the sub up off the floor. Sometimes raising it 1/4 the distance from floor to ceiling works, 2' for 8' ceilings. Make sure whatever you use is solid.

There's also the rule of thirds, full moons, garlic, and maybe putting a ring ground up bricks around the sub.

Offline Sir Thrift-a-Lot

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Re: Anemic subwoofer
« Reply #8 on: December 31, 2018, 01:27:44 PM »

I've found that running leads from amp to line level on the sub and then leads from amp to speakers. NOT using line out on the sub to other speakers. It works better for me.


That will certainly give more bass as the sats are running full range.   Of course the downside may be that the sats are running full range.   It is very system dependent if that will be better or worse.

Offline scorpio333

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Re: Anemic subwoofer
« Reply #9 on: December 31, 2018, 03:30:08 PM »

I've found that running leads from amp to line level on the sub and then leads from amp to speakers. NOT using line out on the sub to other speakers. It works better for me.


That will certainly give more bass as the sats are running full range.   Of course the downside may be that the sats are running full range.   It is very system dependent if that will be better or worse.

Ah yes, I was assuming the sat's had internal crossovers blocking the lower frequencies, it's very possible the crossover is in the sub.

I should clarify that I use my method with full range speakers, I like the sub to extend their range a little lower and give some better impact and resonance. 

Offline OldiesButGoodies

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Re: Anemic subwoofer
« Reply #10 on: December 31, 2018, 05:10:32 PM »
Pepe- Thanks for the tips.  The satellite position is about the same as with the B & O's.  I have only incremental room to reposition them, but can try them closer or further from the rear wall.  I have adjusted the phase setting, but not slowly (yet).  I have not tried the crawl, but the sub is positioned in a fashion consistent with the instructions recommended in the manual.  Finding and using my pink noise generator and measuring gear may be tough, considering the remodeling project and the shape my rom is in

The low frequency performance of the sub is actually not bad, except for the level.

Hi Klaus,  Happy New Year's Eve to you and everyone on the forum...

Do not worry about getting any of you room eq stuff out,  just place the Deftech sub (phase set at zero, volume in the middle) on your listening position (plop it gently on the chair seat,  use a towel to protect the seat if the sub is wearing spikes).   Then play a bass-heavy track while crawling along the perimeter of the room like a cat.  You will find spots where the bass sounds more solid than others and places where there is amlost no deep bass (the nulls).  Then move the sub to one of those places where the bass sounded good to you,  go to your chair and listen to the track,  adjust the sub volume to taste (it may be too high) and you are done.   The difference can be amazing in some rooms. 

P

Spkr: Harbeth 30.1 on Sound Anchor stands
Pre: Rogue 99 Super Magnum
Power:  Rogue Stereo 90 Super Magnum
Phono: VPI Aries 1,  Denon 103R
CD: Oppo 203
Sub: Rhythmik FV15HP

Offline MacGeek

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Re: Anemic subwoofer
« Reply #11 on: December 31, 2018, 10:24:41 PM »
Happy new tear to all and thanks for all of the tips.  I think I am going to do the sub crawl first, in the event I have a severe null, and then pursue the possibility of a sensitivity issue.  If that doesn't fix things, I'll try all of the other suggestions. Regardless, I'll let everyone know what I learn and the solution and hope it's not a trip to the repair shop for the sub.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Tandberg 10X

Offline MacGeek

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Re: Anemic subwoofer
« Reply #12 on: January 01, 2019, 12:31:05 AM »
Well, I disconnected and rewired the entire speaker level signal path, just in case I had an oops somewhere.  No change.  So, I disconnected the speaker level wiring and used the low level inputs on the sub and separately to the amp driving the satellites via a "y" connector coming out of the switch box.  I had to back down the input level gain on the amp to nearly zero , but finally got a reasonable balance between the subs output and the satellites.  I loosely estimate there is at least a 10 to 15 db difference in sensitivity between the satellites and the sub when using the speaker level connections, compared to the low level approach.

Over all maximum system loudness is down considerably, and depending on the source material I can't play it too loud, which doesn't seem to be right.  I have never owned a system I couldn't drive to ear bleeding levels (even when all I had was a 26 watt Pioneer receiver).  Once I get my system up and running, this sub may need a trip to the shop, but it's serviceable in the meantime.

Thanks again to all for your suggestions.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Tandberg 10X