Canuck Audio Mart Hifi and Audio ForumCanuck Audio Mart Hifi and Audio Forum
It is currently Wed Dec 13, 2017 7:03 am

All times are UTC - 8 hours




Post new topic Reply to topic  [ 18 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Sun Sep 17, 2017 9:33 am 
Offline

Joined: Tue Oct 20, 2015 4:22 pm
Posts: 71
Location: Waterloo, ON, CA
I'm getting excessive bass in some audio files. Hard to describe it, but it sounds as if there is low frequency built up. The bass notes are overly extended to the point that it becomes unpleasant. I'm getting this on phono, FM, and through an external dac.

Speakers are custom made with Kef b200 sp1014 woofers and Peerless tweeters (Falcon Electronics crossover) with front ports.
I tried placing the speakers at different distances from the wall, also further apart, but the excessive bass is still there.

Receiver is an old Fisher 550T that has been recapped. I've read that bass can be excessive on some vintage 1st or 2nd generation transistor amplifiers.
I leave the bass control in neutral, and sometimes I reduce it by 3 db but that extended bass is still there

Did anyone experience this before? I'm thinking that the woofer or speaker stands are not isolated well, although I don't sense vibrations when I touch the speaker cabinets or the woofer.
Is it also possible that a capacitor needs to be replaced in the crossover?
I know there are many possibilities, I'm just trying to figure out what is the most likely cause.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 9:53 am 
Offline

Joined: Sat Feb 07, 2015 6:57 am
Posts: 280
Location: North Vancouver, BC, CA
My order of suspects would be
1. Speaker is generally very bassy this includes the crossover design but also the woofer selection
2. Speakers are oversized for room
3. Speakers not properly isolated from floors if theyre not concrete
4. The rest of your components


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 10:24 am 
Offline

Joined: Tue Oct 20, 2015 4:22 pm
Posts: 71
Location: Waterloo, ON, CA
Thanks for the suggestions.
I will check the components in the crossover since they are over 30 years old.
I don't think the speakers are oversized for the living room.

There is no isolation foam between the woofer and the speaker cabinet, can this be an issue?
I am using dollar store no slip gel stoppers between the speaker and the metal stand, and I removed the spikes from the stands as they are on hardwood floor (not real wood)


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 10:44 am 
Offline

Joined: Mon Dec 28, 2009 10:04 pm
Posts: 77
Location: toronto, ON, CA
Try using 3 quarter size balls of mastic putty between your speakers and the stand. 2 in front, 1 in back. Mastic putty= fun tac, stik tac, blue tac, etc. they are all the same and you can get it at any dollar store. There is a great article in the Stereophile archive about coupling speakers to stands.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 10:48 am 
Offline
User avatar

Joined: Wed Jul 23, 2008 5:04 pm
Posts: 1761
Location: saskatoon, SK, CA
Not all putty is created equal.
Avoid the dollar store crap

-- 17 Sep 2017 18:48 --

Not all putty is created equal.
Avoid the dollar store crap


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 11:43 am 
Offline

Joined: Mon Apr 26, 2004 2:33 pm
Posts: 3095
Location: Toronto, ON, CA
Depending on the knowledge and experience of the person who did the custom design, the excessive bass may be a design defect, possibly in the crossover.

Having made or participated in making numerous DIY speaker systems, I can confirm that crossover design, whether active or passive, is definitely a black art. Neither golden ears nor having and knowing how to use measurement equipment is sufficient. Years of experience are the key.

It would be worthwhile to purchase, from the miniDSP website, a calibrated USB measurement microphone and download their free measurement/EQ software. With a laptop, you can then get a precise indication of where (at what frequencies) your speakers are non-linear. This may then require you—or not—to invest in an equalizer.

In a recent issue with a pair of my own speakers, a certain thickness and boominess in the upper bass/lower mids was largely cured by lowering the crossover frequency on the bass drivers from 120 to 100 Hz—even though 120 Hz had been optimal with a different pair of bass modules. But that's just one example of what "the cure" can look like.

Decoupling the speakers from the floor with stands (or something else) is always a good idea. It may or may not contribute to solving your problem.

But, above all, I would want first to get an objective (measured) indication of the frequency response of my speakers before I began attempting to find a solution.

Good luck and (eventually) happy listening!


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 12:00 pm 
Offline

Joined: Wed Feb 27, 2013 8:43 am
Posts: 844
Location: Stratford, ON, CA
Hi,

About various kinds of putty, like Blu-Tak. I used it until it took the veneer off the bottom of some very expensive speakers!! Beware, since as it ages it can get pretty 'tacky'. I prefer rubber grommets inserted between stands and speakers as I belong to the 'decoupling' school of thought - with no stand spikes in the floor.

About the extra bass. Decoupling the speakers will lighten the bass as will getting them out of corners. Furthermore, sometimes a room just has a few nasty resonant frequencies determined by it's dimensions and the composition of the walls and windows and ceilings and the furnishings and that just sucks. Try the system in another room as an experiment - even the kitchen if necessary. See what happens.

I think you know what your speakers can sound like, as you may have built them I am guessing, and so I am pointing my long crooked finger at the amplifier. The early tranny's could be both bass heavy and woolly in the bass region. Borrow an amp from a friend for an evening, or ask a CAMMER in your area to assist. Trial and error is the only way to handle this.

Cheers,
David Neice

_________________
Chinese Proverb: 'Man who waits for roast duck to fly into mouth, waits very, very long time'.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 12:43 pm 
Offline
User avatar

Joined: Wed Dec 07, 2005 11:07 am
Posts: 649
Location: London, ON, CA
Insufficient power to control the woofer would be my guess.

I have a friend who bought a system with large speakers with a 12" woofer, powered by an inexpensive Sony receiver. Every stroke of a classical guitar treble strings was accompanied by a whoosh of air, and he thought that was impressive bass ...


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 1:10 pm 
Offline
User avatar

Joined: Wed Jul 23, 2008 5:04 pm
Posts: 1761
Location: saskatoon, SK, CA
L-Man wrote:
Insufficient power to control the woofer would be my guess.

I have a friend who bought a system with large speakers with a 12" woofer, powered by an inexpensive Sony receiver. Every stroke of a classical guitar treble strings was accompanied by a whoosh of air, and he thought that was impressive bass ...


Isn't that less about power and more about the debatable damping factor?


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 3:03 pm 
Offline

Joined: Mon May 23, 2016 1:19 pm
Posts: 179
Location: Mississauga, ON, CA
All of the above could be your problem. However, some music is just recorded BAD. Or recorded for $100 stereo with over boosted bass. Most recently iTunes download of 2 Heads, Coleman Hell, terrible bass mix, was the sound engineer asleep?


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 3:43 pm 
Offline

Joined: Sun Jan 27, 2008 1:15 pm
Posts: 235
Location: Brandon, MB, CA
You're likely experiencing a bass peak because of how the speaker is interacting with the room. Try pulling them further away from the wall.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 5:45 pm 
Offline

Joined: Mon May 01, 2017 9:11 pm
Posts: 47
Location: Saskatoon, SK, CA
I 2nd the amp cannot drive the speakers properly. You need an amp that can drive a less than 8 ohm speaker. More importantly an amp that can supply current.

Had this bass problem with my Paradigm Studio 100 v2 which is difficult speaker to drive. Receivers I tried all sounded like ass. My Yamaha av/receiver could power them but it wasn't until I got a Bryston 3B ST that the speaker opened up.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 17, 2017 9:30 pm 
Offline

Joined: Fri Jun 01, 2012 8:18 pm
Posts: 965
Location: Richmond Hill, ON, CA
It is a ported speaker. Possibly the port is not correctly tuned. Try moving a book across it, to see if it has any effect. Try stuffing the port with rolled-up socks.
If there is any touch of the sound you get talking through cupped hands, damping the interior might help. I like to see all internal surfaces, except the baffle, covered. I use fibreglass insulation. More fibreglass gives more damping to internal resonances. In some cases, attaching damping to the baffle, covering the woofer, can help.
Good luck.

Cheers,
Alec


Top
 Profile  
Reply with quote  
PostPosted: Mon Sep 18, 2017 5:00 pm 
Offline

Joined: Tue Oct 20, 2015 4:22 pm
Posts: 71
Location: Waterloo, ON, CA
Thank you for all the suggestions.
I tried these speakers with my brother's Nakamichi stereo receiver and even with the tone off, the bass seems a bit excessive.
Perhaps the speakers are very sensitive to room positioning or the ports are not tuned properly (I still have to test this).

The speakers are from a DIY kit from Electronic Today International 1977. Some components in the cross over may have gone bad?


Top
 Profile  
Reply with quote  
PostPosted: Mon Sep 18, 2017 5:12 pm 
Offline
User avatar

Joined: Tue Jun 21, 2011 1:18 pm
Posts: 884
Location: St. John's, NL, CA
malthuse wrote:
My order of suspects would be
1. Speaker is generally very bassy this includes the crossover design but also the woofer selection
2. Speakers are oversized for room
3. Speakers not properly isolated from floors if theyre not concrete
4. The rest of your components



I'm surprised speaker placement isn't on this list. Ie) too close to a rear or side wall. Oversized speakers could perhaps be it. Or speaker design. Nothing worse than a boomy ass speaker for the sake of being boomy.

Also, is there a sub woofer in the mix? Can you tune the frequency cut-off for it?

If the OP is playing vinyl, could the speaker be too close, and at loud volumes be causing feedback in the way of low humming causing the driver to make lots of movement and bass?


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 18 posts ]  Go to page 1, 2  Next

All times are UTC - 8 hours


Who is online

Users browsing this forum: dlnlt and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group