Bass deficiency

There is no reason why your system should be showing a lack of bass.

I would suspect that there is a problem with the set up somewhere. Try repositioning your speakers and see if any of the missing bass returns.

Also try re-conecting all the connections and speaker cables to see if this helps, making sure any directional cable is connected the correct way.

Regards

NB

Some calculations show that because two of the dimensions of your room are close (16' x 15' makes it almost square) you get axial standing waves along the length and width that fall close together. For the longer dimenion you'll have standing waves at 35.3 Hz, 70.6 Hz, 105.9 Hz, and 141.2 Hz. On the 15' dimension you'll have standing waves at 37.7 Hz, 75.4 Hz, 113.1 Hz, and 150.8 Hz. If you place the SBLs at an even fraction of either room dimension you would activate or energize the standing waves for that dimension and boost the bass at the frequencies associated with that dimension. On the other hand if you have the speakers at an odd fraction of either dimension you'd suppress the standing waves for that dimension. This would also be true for your listening position, you may be sitting in a "null" between the peaks of the standing waves created by your room dimensions.

My suggestion is that before you buy any new gear you try different placements for your speakers and listening position. You might also consider buying a copy of the acoustic measurement software for Windows made by ETF Acoustic . It costs only US$150, can use the ubiquitous Radio Shack SPL meter as a mike, and is very powerful. ETF will tell you a tremendous amount about what's going on in your room. There's a bit of a learning curve involved with it but the author is quite responsive to email questions. Another option would be the US$100 Room Optimizer automated speaker placement software from RPG. You input the dimensions of your room, some information about your speakers, limitations on the placement of the speakers and / or listener if any, and Room Optimizer does the rest. For my room it ran through over 1200 iterative models before settling on a recommendation. A third possibility is CARA 2.1 , another room modeling software package. I haven't used it but Stereophile's Kal Rubinson is a big fan.

If you have moved your SBLs, have they been properly set up again? It is possible that the aluminium pads need replacing and the gasket re-sealing after moving them. Just a thought....

Jo

You say you brought the problem from the old house so you were getting light bass there. Are you sure the SBLs' gasket seals are intact? To check, push the main driver in (lightly now!) for its total travel, hold for a second and let go. If the driver takes a couple of seconds to come out (i.e. relatively slowly), the seals are fine. If not, and the driver just bounds straight back, the seals are broken and you need to re-seal the speakers.

Otherwise, ensure the speakers are a good distance apart (around 8 - 9 feet) and I would possibly toe them in by a millimetre or two although that is quite room dependant.

Oh and one day get a decent rack. The usual suspects are Mana, Quadraspire Reference, Hutter and Naim Fraim.

Regards,
Frank.
All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.

quote:

---

Originally posted by David Booth:
I agree with Frank. Repositioning of speakers by only a fraction can make such a difference, as I have recently found. I don't use SBL's so I am not sure about their positioning, but toeing them in might make a significant improvement.
Just keep trying different options.
Yeh, racks also make a great difference, but I'm not going down that road. Audition what you can and hear which YOU prefer.
Cheers,

DAVID.

The music is the most important thing.

---

I have to agree with David on the speaker postioning, also try Granite plinths these definetly 'Tighten' up the bass No end and greatly inhance detail (IMMHO) Racks too can make a signifcant differnece if used correctly, although very recently I have heard of a very intresting method of bass control a servo driven driver Does any one have any info on this and how it would fit into a naim system.

Kind Regards David (another one )

Well Balanced Beings Promote Harmony In Music and Soul

quote:

---

Originally posted by David Booth:
_Thunderbird 2_

Always my favorite Thunderbird. Big green f*cker. Not now in yer face but now gives a feeling of quality and it can do anything you want it to do! Bit like yer system mate.

DAVID.

The music is the most important thing.

---

Why thank you kind sir I have what I feel is average bass control and wish to improve on this greatly and I feel That the massive amount of knowledge of this forum may help to improve/remeday this situation, possibly a speaker change as well you see Thunderbird 2 may be slower but it has huge carrying and lifting potential, which in essence is useful for large amounts hifi equipment moving potential

Kind Regards David (T)

Well Balanced Beings Promote Harmony In Music and Soul

Many thanks for the suggestions. The seal issue on the speakers occurred to me especially as they went into storage prior to their new home. I rechecked the drivers and they seem to return fairly slowly so presumably no problem there. Re positioning I am restricted but have tried some experimemtation without improvment. The peculiar thing is there seems a range of base that is missing - as I said originally I have achieved extremely deep base response from certain well recorded CDs and tightness is not a problem. The unspoken thought out there is probably perhaps this guy is partially deaf but others have listened and agreed with me. By the way no one commented on the dedicated spur question - I presume this would not help the base issue but how does it improve sound and to what extent?

Thanks again for the input
SF

...but there are a cohort of us here who believe the SBLs, good as they are (and I lived with them for 7 years), just don't do deep bass. There's lots of old threads relating to this and I have no intention of raising that old hoary chestnut again but, IMHO, you need different speakers if you want really deep bass - the SBL is wonderfully tight, dry, controlled.....it just ain't deep enough. When I replaced my SBLs a whole octave (or three) suddenly appeared from nowhere. Have you tried something comparable? From what I've heard of the SL2, they share this characteristic as well - you'd need to try something non-Naim? Whilst I couldn't live with Isobarik type colouration, there's no doubt they do bass for example.

Steve

quote:

---

Originally posted by James:
SF,

_The peculiar thing is there seems a range of base that is missing - as I said originally I have achieved extremely deep base response from certain well recorded CDs and tightness is not a problem._

I believe you have the classic problem of cancellation. This occurs when the speakers are placed in a position where, at certain frequencies, the direct waves and indirect (reflected) waves are out of phase with each other and hence cancel. An earlier pair of loudspeakers I had (Sonus Faber Concerto) plumbed the depths nicely down to around 40Hz, but exhibited a –18dB loss around 100Hz.

When I experimented, I found that varying their proximity to sidewalls was just as significant a difference as the same to the backing wall. Furthermore, moving them by small distances made big changes to the balance. As the SFs were free-space loudspeakers, I had to contend with positioning on two planes. Your wall-mount SBLs should make it easier. I’d suggest you get hold of a test-CD with 1/3rd octave frequency test tones, and an SPL meter to find out what is going on. Then fine-tune to a location that pleases your ears.

James

---

James, Thank you for comprensive reply sir, very informative too, I have also experimented with different wall placing, toe in angles, heights various different stands and hanging rugs (to great effect I might add) I feel the best most noticable difference was the addition of a granite plinth, this not only tightened up the bass, but the sound became more defined and the mid band 'appeared' cleaner I do have a very odd room unfortunatly, so I feel only minor pluses will be gained by 'Tweaks'. Recently I have read that 'Room correction EQ' is a great 'Fixer' in the acoustic dept. I was wondering if any of you gentlemen has come across it, and if any advantages to be gained?

Kind Regards David (T)

Well Balanced Beings Promote Harmony In Music and Soul

Fox,

Your gaskets might still be OK, but if the spikes have worked deeper into the pads when being moved (could be unevenly) this could also be a problem which testing the movement rate of the bass cone would not reveal. The amount the spikes penetrate the pads is important, if I remember some posts by Julian Vereker on the old forum correctly.

The way to test this is to remove the bass box and clean the sealant from the top of the gasket. Replace the bass driver box (without sealant)and check that it sits evenly on the pads without rocking and that when you look from the side there is a visible gap between the top of the gasket and the bottom of the bass driver box (where the sealant goes).

If all is well you can then re-assemble with new sealant.

Jo

If rooms are so difficult to adjust for bass and resonance what would it be like to design a concert hall like the Disney hall being built in Los angeles? The seats are to have the same ddensity as a human so resonance won't be altered if the hall isn't filled.
LA PHil web page

quote:

---

Originally posted by silver fox:
System: LP12/CDS2/80/2xHiCaps/250/SBLs

The above has recently been re-housed in a room approx 16' x 15' x 9' with fitted carpets on a timber floor. Sadly the problem that I have brought from my previous home is a lack of base weight. Until the recent purchase of the CDS2, all my listening was analogue. The 12 year old Linn was Cirkused four years ago and an Arkiv put on the end of the LVIII. Doug Hewitson of Manticore (anyone know where he has gone?) further tweaked the deck and added his MB6 power supply. It sits on a fibrolan base on a fairly solid MDF equipment rack. The recently added CDS2 shows that I can get some extraordinarily low base from the system - lower than anything achieved from the LP12 - however it is far too subtle and the weight is missing when either front end is employed. Top and middle frequencies are a delight. Will a Mana/Fraim help? Will a dedicated power supply do the trick? Any assistance is appreciated.

SF

---

Hi Mr Fox,

I had a similar experience recently in terms of losing bass weight, and I discovered I had introduced an Earth loop by adding a connection from my home cinema system into my 62. The effect was dramatic (I really thought I had somehow trashed my Troika, or maybe the Ittok bearings!). I didnt have an earth hum as such - or at least only rarely and faint, but the impact on the music was profound.

Now I read somewhere that Naim CDP's have an earth, and of course LP12's provide an earth also, so the normal advice seems to be to disconnect the LP12 earth spade where it connects into the pre-amp, and let the CD provide the 0v earth point.

Maybe its worth a shot?

Cheers!!!
Chris