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post #1 of 7 (permalink) Old 2017-12-18, 08:07 PM Thread Starter
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Powered Subwoofer Question

Recently i was given a Kef psw2010 sub. When i hooked it up to my Denon 3805 avr i wasn't impressed with the sound. The bass is very mild even with the levels set at their highest. To troubleshoot i hooked up a friend's Yamaha 8" sub and it provided a much louder and deeper bass. I would assume this is an issue specific to the Kef sub but i am wondering if their in something wrong with the sub's amplifier? Just looking for help before i spend money at a repair shop to test what you experienced home theatre gurus might be able to help me with. Thanks.
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post #2 of 7 (permalink) Old 2017-12-19, 01:43 PM
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Could be a number of things.

Make sure Power toggle is ON and POWER switch is set to manual.
Cross-over frequency too low. Set this to max.
Phase Adjustment. Doubtful but try 0 and 180 to see if another bass source is cancelling it out.
Input Level. Put it at 12 o'clock and slowly turn it up to see if the volume increases.
Toggle Music/Cinema. Just in case there is some multi-channel/stereo processing going on.

Make sure both Left and Right line-in are securely connected. I had an issue where the RCA plug was not tight.
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post #3 of 7 (permalink) Old 2017-12-19, 01:56 PM
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Things to check re. Denon 3805 AVR's SW Output, see fol. pages in Owner's Manual. It would help us to diagnose your problem if you could tell us how the AVR is set up NOW and also after you make changes, see pg26 & pg31:
https://usa.denon.com/us/product/hom...eivers/avr3805

1) pg26: Check of the measurement results. Be sure to STORE the RoomEQ Results, otherwise they are lost.....

2) pg27: 1-2 Setting the Manual EQ Setup. INITIALLY you can start with all EQ Settings = 0.0 dB, so you can quickly compare to RoomEQ Results. If you like the RoomEQ settings, you can transfer them across to Manual EQ Settings, except perhaps with different settings for 63 Hz and 125 Hz [Output by SW], per your "Personal Taste".

3) pg28: 1-3 Setting the Room EQ Setup. You can quickly change between Auto RoomEQ Results and Manual EQ Settings.
[Step 3: Recommend you select "ALL" and Step 4: Recommend you select "NORMAL.]

4) pg 32: 2-1 Setting the type of speakers. If you don't set Speaker Size for LF/RF [as per procedure in Manual] prior to running RoomEQ, then AVR will TRY to determine proper setting based on measured Freq Response. BUT, in many cases it will ERRONEOUSLY set it to LARGE, when actual speaker size is NOT 12-in or Larger. Unless you have LARGE Speakers that can hold their own against the Sub-Woofer, you should ALWAYS select SMALL for ALL Speakers. This prevents the LF/RF [et. al.] from TRYING to reproduce Low Freqs when ithey're just not up to the task of providing LOW-DISTORTION at High Power....and let the Sub-Woofer do what it's designed to do instead. This also prevents Low Freqs from LF/RF from INTERFERING with SW Frequency Response. You should do this BEFORE re-running RoomEQ.

5) pg37: 2-5 Setting the low frequency distribution: IF LF/RF are inadvertently set to LARGE, then SUB-WOOFER MODE = "LFE+MAINS" will result in Low-Freqs from LF/RF ALSO being routed to the SW Channel. This is important when listening to STEREO (and Synthetic Surround), since otherwise the SW Channel would have NO Signal. However, if you set LF/RF to SMALL, then LF/RF Low-Freqs are already being routed to SW Channel. You should do this BEFORE re-running RoomEQ.

6) pg40: 3-2 Setting the Ext. In Subwoofer Level. Allows you to adjust AVR's SW's Output level going to SW....note that DEFAULT is at Max = + 15 dB. You should do this BEFORE re-running RoomEQ.


7) pg34/35: 2-3 Setting the Channel Level. FINAL TWEAKS to SW (and other Speaker Levels) can be entered while listening to Test Signals being output from each Speaker.

================================================
Note that AVR only has TWO FILTERS available for the entire 20-200 Hz Bass Frequency Region, with actually only ONE Filter (centered on 63 Hz) available for Sub-Woofer when using typical 80 Hz LFE Crossover Frequency Setting. Since there WILL be one or more fairly narrowband RESONANCES in the 20-80 Hz spectrum due to ROOM MODES, this single Filter will TRY to ATTENUATE the primary Room Mode Resonance....resulting in the appearance of "Weak Bass" on other Low-Freqs. So you will probably want to BOOST the SW Level and/or REDUCE the 63 Hz Filter Attenuation so you can HEAR the OTHER Bass Notes. [BTW: Yamaha AVRs with YPAO PARAMETRIC Equalizer uses Filters with variable Center Frequency and "Q" (inverse Bandwidth).]

If you REALLY CARE about HEARING ALL of the Bass Notes, I recommend inserting a 1/3-Octave Equalizer in-between AVR's SW Output and SW Input which provides SEVEN Filters for 20-80 Hz SW Channel to attenuate MULTIPLE Narrowband Resonances while also reducing the NULL Depths, such as 2-Channel Unit from Monoprice...which can independently equalize up to TWO SW's: [You may also have some minimal controls on your Sub-Woofer you could try].
https://www.amazon.com/Monoprice-31-.../dp/B00KLRP5CK

Room Equalization (via means other than AVR) for the 1/3-Octave Equalizer MUST be done PRIOR to running AVR's RoomEQ (which will Equalize from LFE Crossover Frequency and up. This can be done using a Calibrated Microphone and computer (or Cellphone) Software...or manually using a Sound Pressure Level Meter with integrated Calibrated Microphone and a 1/3 Octave Test Tracks (Download or Disc).....a LOT more on this subject is found here:
Please Help me understand my system - AVS Forum | Home Theater Discussions And Reviews

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #4 of 7 (permalink) Old 2017-12-19, 02:49 PM Thread Starter
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Thanks for all the info but I don't think the poor performance of the Kef sub has anything to do with the avr. I have the speakers set to small, the mode in setting 2.5 as lfe, the gains are maxed out and it produces weak bass. I have hooked up other subs to the avr and not touched any of the settings and they have pounded much harder than the Kef. I am just wondering if it could be an issue with the sub's amp or something due to there being some bass produced, just not nearly as much as the other subs I have connected to the avr.
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post #5 of 7 (permalink) Old 2017-12-20, 01:34 PM
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Have you removed the subwoofer grill and checked the speaker for damage and movement when being driven?
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post #6 of 7 (permalink) Old 2017-12-20, 02:12 PM
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You've probably played with KEF's controls already....but, FWIW, per the Manual:
https://www.manualslib.com/download/...f-Psw2010.html

1) MUSIC (vice CINEMA) provides Deeper Bass.

2) FREQUENCY CONTROL should be set for 140 Hz (the Maximum). The LFE Crossover Filter in the AVR should be the ONLY Filter controlling the SW High Frequency Roll-off Characteristics. IF both AVR and SW were set to say 80 Hz, then a significant DIP in the Frequency Response would result in vicinity of 80 Hz (70-110 Hz) resulting in "Weak Bass".

3) SLOPE 12dB/24dB: Try BOTH settings....in the hope that only ONE of the Filters is possibly defective????

4) PHASE: Try BOTH settings, as mentioned in earlier post.

AND, as always, try different room LOCATION, LOCATION, LOCATION.
You might also want to try the "SUBWOOFER CRAWL".

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #7 of 7 (permalink) Old 2017-12-21, 12:07 PM Thread Starter
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Yes, i've had the sub out of the box and it doesn't appear to be damaged or it's movement inhibited in any way. I have the sub set to "cinema" as that provides louder and deeper bass. The sub itself is set to 140hz. Is there a setting on the avr that i should be looking for other than the sub levels and lfe? I have the crossover freq set to 120hz and my speakers are set to "small".
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