Too much bass??

[BigE]

Here’s the set-up:

• PrimaLuna Prologue 3 preamp
• PrimaLuna Prologue 7 Monoblocks, 6550 tubes instead of KT-88s
• Monitor Audio GR20 speakers
• Analog Source – MMF-5SE w/ Grado Cart.
• Digital Source – NAD M-55 multidisk player
• Interconnects by Grover, speaker wire is generic medium gauge zip cord
• Solid Steel rack. Top shelf holds a 100 pound slab of 2” granite set on three resilient tile feet (1” x1”) and on top of that is the TT sitting on three spikes.
• Speakers set about 15 inches from the wall; toed in to a sweet spot about nine feet away. Room is 12 feet wide at this point and opens up to 22 feet wide past the right channel speaker. Left channel speaker is not in a corner as it sits next to a hallway going back about another eight feet. Ceilings are low; about 7’-9”. Floor is carpet on concrete slab. Speakers are spiked.

Here’s the media:

• Redbook and standard LPs everything sounds balanced and “normal”
• DVD-A (Knoffler’s Shangi-la, Morph the Cat) bass is very strong and ‘upfront’
• 180 gram LP (Petty’s Highway Companion) bass is very strong and ‘upfront’
• MOFI Original Master standard weight (Tull’s Aqualung) bass is strong and clear but also somewhat out front

Here’s the problem:

At higher volumes (not earsplitting by any means) the bass is almost overwhelming on High Res digital and Hoffman-Mastered analog. I think it is safe to say that mastering is not a suspect here. Maybe this is the way it is supposed to sound?? I’m just not used to this much bass response, but this rig is fairly new. I know no one personally that has a system anywhere near this good to compare with. (no close friends are even at the Mid-Fi point yet) If this is the way it is supposed to be, I’ll leave it alone. If not, what do I do to moderate the bass output?

Need a solution:

1. Port plugs for the speakers? Will I need to swap these in and out depending on what media I’m playing.
2. Room Treatment? What kind and where? (generically speaking since I didn’t provide a room sketch.)
3. Look at 6L6s or EL-34s instead of the 6550s? I really don’t want to take a power hit.

Any suggestions are appreciated,

Eric

[bdiament]

Hi Eric,

The topic is big but for starters, see if these articles help:

Setting up your monitoring environment
http://www.barrydiamentaudio.com/monitoring.htm

Vibration control for better performance
http://www.barrydiamentaudio.com/vibration.htm

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

[DaleH]

My speakers get boomy in the bass that close to the wall. Two and a half to three feet out and the bass evens out.

[dgstrat]

I had a similar issue in my 2nd room, which is 16 X16............My Kef 104.3 speakers were simply too large and bassy for the room.I thought I was upgrading the speakers, but i downgraded the sound in that particular room. ........Solved problem with a smaller pair of speakers on stands.........Your room is narrow where the speakers are placed, so I would just sub a different speaker to test it out.

[BigE]

Barry, Thanks for the shout back. Helpful links to say the least.

Dale, If I moved the speakers that far out into the room they'd be headphones. Maybe if I had a new room . . .

Porziob, An astute observation in the first sentence. One I had considered myself. The second sentence . . . WTF did you say?? Low dampening factor adversely affecting . . . poor cone control? Whoa, you gotta dumb it down a little for me. If you would be so kind as to present that second thought again in a little bit more depth? You may be on to something, but I don't know what it is. LOL

Darren, Thanks for your feedback. When I auditioned these they were in a treated room that was roughly 10 x10 to 12x12. They were a little bass heavy on the high rez digital food I was feeding it and they were at least 24 inches in from the back and side walls.

Thanks to all who chimed in so far!!

[Casino]

Most (though not quite all) speakers sound better more than 15 inches from room boundaries, as Dale pointed out. Most of the manufacturers of cone speakers I've owned recommended 3 feet or more. In my case they're about 2-1/2 feet from the side walls and 3 feet from the rear wall.

Even though you say 3 feet from the rear wall would bring the speakers too close, give it a try to experiment. If it helps, at least you've got the problem defined.

[Ethan Winer]

Eric,

> Room Treatment? <

That's my guess. Changing vacuum tubes etc won't - or shouldn't - change the frequency response by much if at all. Most gear is acceptably flat unless it's broken. On the other hand, most domestic size listening rooms have a bass response like the graph below. Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step.

So which do you think is the more likely culprit? :D

--Ethan


http://www.realtraps.com/art_response.gif

[Sneaky Pete]

Here’s the set-up:


At higher volumes (not earsplitting by any means) the bass is almost overwhelming on High Res digital and Hoffman-Mastered analog. I think it is safe to say that mastering is not a suspect here. Maybe this is the way it is supposed to sound?? I’m just not used to this much bass response, but this rig is fairly new.

Eric

What you may be hearing in part is due to the Fletcher-Munson curve. This is an acoustic effect that causes bass to sound much quieter at lower volume levels. Originally the loudness buttons were intended to compensate for this effect at quieter listening levels. When you turned up the volume you were meant to disengage the loudness because the proper bass balance would be restored. In my experience most casual listeners never bothered with the second step.

I am not a real techie if I have mischaracterized the effect or botched the explanation some of you who are more qualified please elaborate or clarify.

As to your problem I concur with the majority; bring the speakers further out from the walls. Placement is tricky and over time you may be fine tuning the location of speakers an inch at a time. Then you can seek counseling for the affliction, like many others have before you.:laugh:

[dblfntsy]

I say to use port plugs.

[wgriel]

Eric,

> Room Treatment? <

That's my guess. Changing vacuum tubes etc won't - or shouldn't - change the frequency response by much if at all. Most gear is acceptably flat unless it's broken. On the other hand, most domestic size listening rooms have a bass response like the graph below. Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step.

So which do you think is the more likely culprit? :D

--Ethan

Hey Ethan,

is that graph typical of an (untreated) in-room response? I had no idea it would be so ugly!

Bill

[DaveN]

Just to clarify about speaker placement. The distances that everyone is throwing out reflect the distance from the baffle (front) of the speaker to the wall. I agree that 2.5 feet to 3+ feet is optimal.

I'd advise that you 'beta test' this by moving the speakers out that far - even if it presents a decorating challenge. Just see if your bass issue changes. At least you'll know what you are up against. Whether you can keep the speakers there is another issue.

[JBStephens]

I say to use port plugs.

I don't recommend doing that. To state as simply as possible, ported speakers are designed to provide an air load on the woofer at resonance. As the bass frequency approaches the design resonance, you'll notice that the woofer is hardly moving at all, the majority of the bass output is coming from the port. If you plug the ports, that design resonance and woofer air load disappears, and you risk physical damage to the woofer from over-excursion. If you plug ports, be VERY careful with volume levels.

Your listening position might be in a standing wave. Try moving around the room and see what happens to the bass levels.

[DaleH]

Your listening position might be in a standing wave. Try moving around the room and see what happens to the bass levels.

Good point, I have standing waves in my room, just not at the listening position.

If you can return the speakers you can look for a set that works better close to the wall.

Dale, If I moved the speakers that far out into the room they'd be headphones. Maybe if I had a new room . . .

Many people listen in near field setups and swear by it. Try it and see.

[Ski Bum]

Big E:

With all respect to the prior posts, they have ignored the fact that you said the system sounds fine with normal weight LPs and redbook CDs but bass-heavy only with heavy thickness records and DVD-As.

With respect to LPs, that is a classic VTA (vertical tracking angle) problem. If your rig is sensitive to VTA adjustment, you need to raise the pivot point of the tonearm to accommodate the thicker vinyl. The classic symptoms of having the pivot point too low are (a) boomy, muddy, uncontrolled bass, (b) poor imaging and (c) some loss of information and detail.

With respect to DVD-As, please make sure you have the menu on your disc player and wiring of your system set properly so that you are not dumping the multichannel signal into two channels. This has the effect of doubling up the bass signal because of the extra sub channel.

[Taurus]

Originally the loudness buttons were intended to compensate for this effect at quieter listening levels. When you turned up the volume you were meant to disengage the loudness because the proper bass balance would be restored. In my experience most casual listeners never bothered with the second step.Most loudness circuits in my experience automatically decreased their effect as the volume is increased and at a preset level (this was kind of an educated guess on the designer's part) it basically turned itself off. My Pioneer SX-6 receiver bought in 1983 for $220 has it. Usually only very old gear or more modern, really cheapo gear omit this automatic aspect.

Anyway....

[Metralla]

Good observations Ski Bum.

[BigE]

Damping factor (usually the higher, the better) is the ability of an amp to electronically control the movement (the starting & stopping) of the cone so it doesn`t continue moving after the signal to it has ceased. This tends to be more of an issue w/ larger woofers. I believe those in the GR 20 are 6"/61/2". They shouldn`t need more damping than a tube amp can supply, so this is a longshot fix. I tend to agree w/ others that your spkrs. need to come forward from the wall @ least 21/2' to 3' ft. If you want a better explanation of damping factor, google it. There`s plenty of info out there.

Thanks Jerry! Makes more sense to me now. I appreciate your expanded response to the first post.:righton:

Eric

[BigE]

Big E:

With all respect to the prior posts, they have ignored the fact that you said the system sounds fine with normal weight LPs and redbook CDs but bass-heavy only with heavy thickness records and DVD-As.

With respect to LPs, that is a classic VTA (vertical tracking angle) problem. If your rig is sensitive to VTA adjustment, you need to raise the pivot point of the tonearm to accommodate the thicker vinyl. The classic symptoms of having the pivot point too low are (a) boomy, muddy, uncontrolled bass, (b) poor imaging and (c) some loss of information and detail.

With respect to DVD-As, please make sure you have the menu on your disc player and wiring of your system set properly so that you are not dumping the multichannel signal into two channels. This has the effect of doubling up the bass signal because of the extra sub channel.

Hal,

Excellent points! I don't have a monitor hooked up to the NAD so it is a crapshoot what layer is playing sometimes. As for the VTA being out, I'm not sure the Music Hall table is that sensitive. The bass isn't bad, just a little out front if you know what I mean. When I auditioned the speakers, they were running off the same NAD player into a 180 WPC NAD integrated (Master Series) and the bass was strong on the Hi-Rez demo discs I brought. It really isn't a problem on most DVD-A or SACD media. Just the ones I listed before. Shangri-la and Morph the Cat. The others seem pretty much right on. Even organ music has tight, well-defined bass; just not too much of it. It is entirely possible I'm inadvertantly playing the wrong layer.
If the VTA were the culprit, the MOFI Original Half-Speed Masters (from the late 70s - early 80s) would not be having the same symptoms since they aren't "heavy weight" LPs would they?

Thanks for the tips. I got some experimenting to do I guess.

Eric

[bluesky]

Thanks bdiament for the links to setup. Will Do!!!!!

[Ski Bum]

If the VTA were the culprit, the MOFI Original Half-Speed Masters (from the late 70s - early 80s) would not be having the same symptoms since they aren't "heavy weight" LPs would they?

Eric
MFSL did make some 180g records at the end of the firm's first life (such as Nevermind, Clapton and Derek and the Dominos in Concert -- I believe they called them Anadisc or something like that), and the UHQRs were on heavy vinyl. . In any event, the MFSL Aqualung LP to which you refer is normal weight so any bass-heavy problem with that record is probably not VTA-related. I don't have the record (I have the DCC version), BUT a lot of the MFSL records were mastered with the bass and highs boosted -- the infamous "smiley face" EQ -- so if you are finding that the bass is just somewhat prominent, the mastering may be the issue.

Petty's Highway Companion 180g LP has reasonably well-balanced sonics on my system. If it is bass heavy on yours, I would suspect that VTA is, at the least, contributing to the problem.

[BigE]

Thanks Hal. I'll check the VTA although Joe N-H at Saturday Audio looked it all over a few weeks ago when I had it in for a tonearm adjustment. Thanks for taking the time to respond!

Eric

[Ethan Winer]

is that graph typical of an (untreated) in-room response? I had no idea it would be so ugly!

Yes, absolutely typical. That graph is from my first article Room Acoustics for EQ magazine:

http://www.realtraps.com/articles.htm

There are many other related articles listed on the same page.

--Ethan

[Ski Bum]

Thanks Hal. I'll check the VTA although Joe N-H at Saturday Audio looked it all over a few weeks ago when I had it in for a tonearm adjustment. Thanks for taking the time to respond!

Eric
Keep in mind that a VTA that is correctly set for a normal thickness record will be wrong for a 180g record -- the tonearm pivot will be too low (by an amount equal to the incremental thickness between a normal and 180g record). A low pivot point produces bass heavy sonics (and some other ills).