Speaker‘s mid/upper bass boost is obvious. Solutions?

Hi all,

I am using Paradigm Signature S2 version 2 as my mains in my family room. There are obvious mid/upper bass bloats during certain songs playback.

Here is the measurements for Signature S2 version 1, which uses the same enclosure design and woofer. The difference is only in the tweeter, thus should be valid to evaluate the mid/upper bass bloats issue:



As you can see, there is obvious boost between 100 to 200 Hz.

Plugging the port in this case would not help, I think. Other than using eq, any other way to solve the issue?

Thanks!

 

You can do no harm with socks in the port as an experiment. You're risking some old socks and 20 minutes.

Otherwise, you start getting into the joy of changing placement to see what you can achieve with speaker/boundary relationships.

Start with the socks and let us know what you think!

Also, the anechoic frequency response curve often has nothing to do with what's going on in your room.

Also in the mix: room treatment options even if you can't change speaker placement.

 

Thanks!

My speakers in the room indeed has the bloat problem based on the actions taken by the room setup software. My preamp‘s auto room setup reduced 120 Hz by ~3db, I believe. I have moved the speakers a few times (limited in how much I could move) and I heard the bloat each time.

With EQ on, the bloat issue significantly reduced. However, I do not really like the eq results. It made 110 and 100 Hz a bit too low as a results. Made music sounds a bit thin.

Also, I did stuffed the ports a while back and as I recall it did not help. : (

May be is time to try a different pair of speakers and see if the bloat issue is room based or speaker based.

Thanks again!

 

Can you describe the current placement?

Are they on OEM stands?

I'd keep making small placement changes. Not just distance from walls, but from floor / ceiling as well.

Over the weekend I moved a pair of Totem Sttaf no more than a few inches in a couple of directions in my living room stereo set up, including toe-in, and it had a noticeable effect on the bass performance. (At least I thought it did when I listened to them yesterday.) And these are speakers that are already not backing up against a wall, and are three feet from the side walls.

Jeff

ps. If you get absolutely fed up with them I'd be happy to alleviate your suffering by covering the cost to ship them to me to get them out of your sight.

 

Haha. I am not giving up yet. : )

Yes, those are on Paradigm J-29 stands, which are designed for Paradigm Studio and Signature bookshelves.

Currently they are about 3' from the front and side walls. About 10' apart and about 11' from listening position. I had them closer to walls before and didn't help. My placement options are really limited. : (

Certain songs sounded just great, but then certain songs with lots of 100 to 200 Hz tones can sound bloated.

I think it is time to spend lots of time doing REW measurements with multiple minor speakers placement changes. : (

Thanks again!

 

Can you manually tweak the auto setup? If so, see if you can narrow the Q on the 150hz reduction so it doesn't affect the 100-110hz range.
If that doesn't work maybe add a decibel or a half back instead of using the entire correction.

 

Thanks!

Unfortunately, the eq capabilities of my Marantz preamp is very limited. May be 8 fixed frequencies to adjust (no ability to select 150 Hz or 100 Hz, etc, other than one fixed one at 120 hz and only can add or reduce dB. : (

I do have minidsp (non HD version), but don't want to use it for main speakers. I think it is only good for subwoofer adjustments.

I am very curious if this is speaker specific or placement specific issue. I will try with different speakers soon to compare.

 

Can you get them further from the wall behind them? Even a few inches might help.

Also, try toeing them in really tight, so they are angled to meet behind your head. This will give you more highs and mids and should help balance out the tonality of your speakers.

I had bass issue with my current speakers and the two suggestions I made above helped a lot.

 

Thanks for the suggestions.

Moving further from wall behind more than 3' would be tough due to foot traffic issue.
Speakers already pointed behind my head.

Will continue to make small adjustments and listen. Really need to do REW measurements soon. The family room is kind of tough to tackle due to large openings on the right and protruding fireplace on the left. : (

 

I'd be curious to see measurements around the listening position, compared to the mic right almost touching the woofer cone. If both have a bump, it's the speaker. If just the room has the bump, it's the room.* Also a measurement with the mic stuck actually into the port a bit, to try and see if that's affecting the upper bass much.

Besides socking the port again as a re-check, you could stuff the enclosures (not touching the woofer cone or blocking the inside of the port). This will make the enclosure act bigger and lower the response of the woofer/port combo. The excellent "Loudspeaker Design Cookbook 7th Edition Book" from www.parts-express.com! has a chapter about this with all different materials tested; IIRC fiberglass and rock wool and Acousta-Stuf were the champions but I haven't read it in a long time.

*Or you just happen to be at a bad combination of distances from walls/ceiling/floor, the "Allison Effect" and if you can't really move the speakers, you might need multiple-woofer towers to get away from this spacing problem. Allison made speakers with like the woofer on the floor and the mid/tweet up high. The tweeter was a cool kind of pulsating nipple.

 

Thanks. I will start the REW thing soon....I did that many years ago, but have not used REW since.

I have HDMI capable laptop and non-USB omni mic with related hardware to get started. First I will need to install latest version of REW, read up on user guide, etc.,etc....probably will take me a while to get going....

 

Just found out the issue is my room and my sitting position. The issue is not limited to just between 100 to 200 Hz. I measured with both Paradigm S2 and KEF LS50. Both got kind of similar kind of response... : (

Here is an example of LS50 measurements, with mic 1 ft away (blue trace) vs ~12.5 ft away at sitting position. I am using 1/12 smoothing.



At sitting position, I got quite a few peaks from 300 Hz down. : (

 

Putting speakers the same distance from the front and side walls is going to exacerbate whatever room boundary related peak or null you're getting relating to that 3' distance. I'd play around with the speaker position so they're either much closer to the front wall or much father away from the front wall and either way not have the distance to the side wall be the same. And it's not just speaker-boundary interference and reinforcement that matters it's listener-boundary distances as well, so I'd play with listener positioning too, including maybe trying some nearfield listening. The good news is that above 125 Hz it can be relatively easy to improve problems relating to boundary interference response with porous absorption. Do you have any treatments in this room?

 

Thanks! Next is moving the speakers around and measure.

With nothing else changed, I measured from a couple ft in front of sitting position and got similar kind of graph. So sitting further in the room seem not helping when keeping speakers at same distance from walls.

No treatments in this room. May consider some after more measurements.

Thanks again!

 

@chervokas made a great point, to make sure that woofer distances to various boundaries are all different, so that you distribute the room effects across multiple frequencies.

 

Yes, will try different distances combinations. I will move items away from the speakers next, including 100+lb subwoofers, to free up some spaces. Thanks!

 

There is a phenomena known as 1/4 wave bass cancellation. Most people don't want it, you want it to work for you and cancel out the peak you are experiencing. Careful placement closer to the wall in accurate steps- e.g. 6"- and then measure the response if possible.

Speaker Placement 101: Is Speaker-Boundary Interference Killing Your Bass?

 

Yes, will move the speakers little by little and do measurements. Having the ability to do measurements will be a big time saver for me. Should have done REW months ago.

Thanks!

 

Hmm. What crossover adjustments can you make in the Marantz? Can you leave the subs crossed low, but increase the highpass frequency to the satellites? That could reduce the energy into the midbass.

 

Looking at the chart I'm curious what you are hearing. The chart is +/- 3db from 45hz through the mids and into the highs. The graph doesn't seem to fit the description.

I'm curious what it isn't showing. Could the smoothing be hiding something?
Or is there a ringing that doesn't show on this graph? A waterfall plot would show ringing.

Or am I reading this wrong?
Is the mic calibration file loaded into REW?

 

Thanks for the tips!

Actually, the measurements were taken using pure audio and subs were not involved. My original post about music was also observed when playing with just speakers and no subs.

Adding back the subs will again require lots of measurements in the coming days.

BTW, the Marantz can't use different crossover for sub and main speakers. To do this, I think I would need to add midsp to the chain.

 

Curious, are you reading the top blue line only?

That blue line was measurements taken with mic about 1 ft away from speaker. This is just to show that with less room effects, the whole chain is OK. So it is used as a good baseline to compare.

The bottom brown line is measured with mic placed at sitting position. This is what I actually would hear when sitting on sofa to listen to music. Use 100 Hz as example, it was measured at 70 dB. All freq from 1.2k and up are less than 60 dB. For example, 10K is about 55 dB. So that is 15 dB difference between 100 Hz and 10k hz. I am not sure how this line could qualified as +/- 3db from 45 Hz up. Shouldn't this +/- 7db? Would you please explain more?

Thanks!

 

Those results are not uncommon, you have room effects from 300 Hz and below. That is why quite many use parametric EQ corrections below 300 Hz.

 

Oh, I was reading them backwards. I thought the top line was at the seating position and the bottom line was a measurement of the woofer. Yikes. Now I get it. Start moving stuff around and measuring I guess.

Both measurements are with the sub off? Curious how the octave from 20 to 40hz is the loudest part of the lower line.

 

It sounds like a standing wave problem in the room (created by the room's dimensions) if every speaker introduced to the room triggers the same room boom issue. It's not easy to alter a room's dimensions but I used to resort to the trick of opening doors. The open door (acting exactly like a speaker port) sometimes would de-tune the problematic room modes.

I also agree that room boom requires a trigger (usually a loud bass peak created by boundary reinforcement and/or the port resonance). If you can prevent this (by playing around with positioning so that the speakers are a different distance from each room boundary and also using solid plugs in those speaker ports) that may prevent the room modes from being set off.