I'm Looking to Upgrade My Current Sound System

[Phileas]

From the review I linked to the AVIs seem quite good, and might be of interest to our OP. However it did seem to me that they are not so good on extreme bass... though they can be coupled with a sub woofer...I know from experience with cheapish AV set ups that a badly integrated sub woofer can render the SQ significantly worse

(Apologies for snipping your post)

The AVI sub was (according to AVI) created because of the lack of sufficiently high quality subs on the market.

There is also a floorstander in the AVI range, the ADM40, which reaches lower (quoted at -6dB at 40Hz) and which I find to be entirely adequate for all the music I listen to. (I listened to the ADM40 with and without the AVI sub (turned well up) and couldn't hear a difference).

There will also be a small 5" two-way active (minus DAC/pre) later in the year, which AVI are very excited about.

[Gordon]

From the review I linked to the AVIs seem quite good, and might be of interest to our OP. However it did seem to me that they are not so good on extreme bass. Arguably few speakers are, but I have heard some (traditional, and old designs - not necessarily "state of the art modern" - there were some good speakers 30 or 40 years ago!) which do/did a significantly better job than most with the low frequencies. Some traditional designs did manage to get down to around 30 Hz with a significant output. Doing that without boom or cabinet resonances is hard, and in any case is likely to require larger speakers - which might not fit in with room and aesthetic constraints.

The AVIs are fairly small I think, though they can be coupled with a sub woofer, which might improve things at the low end. I once heard some LS3/5A speakers coupled with a sub woofer. The subjective SQ went from very good to excellent when the extra bass unit kicked in. However, I know from experience with cheapish AV set ups that a badly integrated sub woofer can render the SQ significantly worse, and even with blockbuster movies, where this might be expected, the results can be undesirable and overwhelmingly horrible. On classical music such sub woofers could be a disaster if not carefully matched to the rest of the system.

Sound without adequate bass is not satisfying even though for much music a weak bass isn't a problem so when it is added it is a revelation! When it comes to bass extension - and I mean getting down to 30 Hz and those deepest of organ pedals and bass drum beats many modern speakers don't get there. Bottom note on a bass guitar is 41 Hz. My speakers produce a very satisfying deep bass [I love organ music] going down to 30 Hz without stress but they are large! If you want better than this sort of performance you have to attack the problem seriously.

To reproduce deep bass a lot of air has to be moved and a small enclosure will find that hard however it is designed or constructed - an active device in the bass is not really any different from a conventional speaker. Deep bass needs a largish enclosure with either large drive units [the old fahioned way - eg Tannoy etc as used by Decca in the early days] or smaller ones wilth long throw which adds to the design constraints. Adding a sub-woofer is only adding external enclosure volume in effect.

Many years ago the then editor of HiFi News [John Crabbe] took up his floorboards and built two flared horns made of cement with their throats coming up between his conventional speakers. He was getting strong response down to 16Hz [only an octave I know] and in his decription mentioned a sense of his trouser cuffs moving in the breeze!!! I wish I'd kept that set of issues - maybe they are on-line these days. I know of someone I used to work with who built a single column loaded speaker using an unused chimney!!

PS: see here for Crabbe's articles:

http://www.saturn-sound.com/history/hi-fi,%20diy%20projects.htm

go down the page a bit to find it. There are also some other interesting articles on speakers there too.

Having said all that how much music actually produces that depth of bass anyway [opening of Rheingold - that long Eflat?], and how much is actually captured by recording media and then reproduced!! Digital systems do that but old analogue systems from the "golden age" certainly had problems doing it.

Try converting an LP to digital and then get Audacity or the like to make a spectrum of a section of the sound and you'll see the problem in the region below 100Hz. You don't want bass extension if your turntable is a bit rumbly.

[johnb]

The other factor when discussing bass is the actual room you are listening in - it's dimensions, the speaker locations, the listening position(s), level of damping, the peak and null effects due to standing waves in the room and the compromises you are willing to make between aesthetics and audio.

If you play a single low frequency tone on your audio system, depending on the frequency and the room modes, you can hear the sound level dip and increase as you walk round the room.

For example, my living room is roughly 15' x 17' x 10.5', wooden floor extensively covered by rugs, two wall hangings but no curtains (I use the shutters as it seems such a pity to hide the lovely ceiling to floor woodwork surrounding the windows).

My speakers are PMC FB1+ and a REL Strata 5 Subwoofer, powered by a Meridian G55 power amp running in stereo bridge mode (300 watts per channel).

I've measured the frequency response at various listening positions (using REW software, DRC software and a calibrated measurement microphone) and I can get a reasonably flattish response down to 15 Hz by at my listening position. But, there is always a trough of 10 to 16 dB, between 36 Hz and 48 Hz due to the room standing waves at that position. Dramatically moving the seating position would help but there are practical restrictions - and so (I presume) would increasing the damping with curtains.

PS I have started looking at using Digital Room Correction with my Squeezebox to somewhat reduce the trough (eliminating it would be totally unrealistic).

[Phileas]

there is always a trough of 10 to 16 dB, between 36 Hz and 48 Hz due to the room standing waves at that position. Dramatically moving the seating position would help but there are practical restrictions - and so (I presume) would increasing the damping with curtains.

I don't think you can damp low frequencies with curtains, you'd need proper bass traps.

[johnb]

I don't think you can damp low frequencies with curtains, you'd need proper bass traps.

Yes, of course you are right.

[Gordon]

JB, your #78 raises a very relevant issue of course. My room is a little larger than yours and from a bit of investigation, not as thorough as yours, I get similar eigentones but slightly lower in frequency. One can hear them in a tone sweep from a test source.

I have found that the effect of these resonances can be mediated by leaving the living room door to the hall open by about 45 degrees and the sliding doors into the dining room part open too when they seem to act as crude untuned bass traps!! It is not perfect and not scientific either but it does take the sting out of room resonance. I haven't tried the effect of opening windows for the obvious reason, but the curtains when closed certainly help with higher resonances as one can readily hear!

Another way to help deal with room resonance is to have the corners occupied with something solid and also to have odd shaped items like furniture placed carefully, distaff willing of course, in order to distribute the sound and break up the major resonances into more less troublesome ones. Don't have the speakers aligned parallel with or too close to walls either. Mirrors, glass fronted cabinets and large picture frames on walls are not a good idea but there again domestic order rules!

What we do to get decent sound!!

[Dave2002]

Many years ago the then editor of HiFi News [John Crabbe] took up his floorboards and built two flared horns made of cement with their throats coming up between his conventional speakers. He was getting strong response down to 16Hz [only an octave I know] and in his decription mentioned a sense of his trouser cuffs moving in the breeze!!! I wish I'd kept that set of issues - maybe they are on-line these days. I know of someone I used to work with who built a single column loaded speaker using an unused chimney!!

I met him once at/after a Prom concert. He confessed that he also had a button under his chair which when pressed switched on an oscillator at around the very low Hz which got mixed in with the signal from the music. He'd then play something like the Saint-Saëns 3rd symphony, and at judicious points in the music push the button, which made the chairs and the room shake a bit for extra effect. He said it didn't matter much what frequency the oscillator was at - you couldn't hear the tone, but only feel it!

[Resurrection Man]

I met him once at/after a Prom concert. He confessed that he also had a button under his chair which when pressed switched on an oscillator at around the very low Hz which got mixed in with the signal from the music. He'd then play something like the Saint-Saëns 3rd symphony, and at judicious points in the music push the button, which made the chairs and the room shake a bit for extra effect. He said it didn't matter much what frequency the oscillator was at - you couldn't hear the tone, but only feel it!

I had the hutzpah to contact him, as I lived close by, and ask if I could come and have a listen. They really were superb.

[Beef Oven]

I had the hutzpah to contact him, as I lived close by, and ask if I could come and have a listen. They really were superb.

Nice one Cyril

[Nevalti]

......I use a computer and a nice pair of headphones to listen to the radio/music (not a great sound system I know ). I've never owned a CD player or Hi-Fi but would now like to purchase a sound system? If that's the correct term, I'm not sure where to start or what I need to be looking for.

Any advice would be greatly appreciated.

I'd also be interesting I knowing how you listen to your music?

BWV 988

With all this talk of Active Speakers I think it may be helpful to outline some speaker basics. Active speakers can of course be absolutely fine but they are inevitably a dead-end compromise because once you have bought it you can’t change anything without tearing the box apart. It’s almost like having a Radiogram

You will obviously be aware of the ubiquitous rectangular box speakers. They come with various numbers of drivers (most commonly 2 or 3) and can all sound good but they suffer from the problem that one driver cannot provide all the frequencies and also the sound at different frequencies come from different places. The electronic cross-over between 2 drivers commonly occurs right in the middle of the human speech frequencies – which is obviously a bad thing. The cross-over networks all too often upset the phase of the drivers and imaging is ruined. Poorly designed cross-overs also provide an uneven frequency response – even on some very expensive speakers. A well made three driver speaker is likely to be better for vocals as most voice sound will come from the mid-range driver. To complicate matters, there are some ‘dual concentric’ drivers which place the tweeter in front of the woofer. They help with imaging but do not remove the cross-over problems.

To complicate things more – they come in 5 basic designs:
1. Sealed box (also called infinite baffle) – the simplest and cheapest design but usually bass light.
2. Ported (also called bass reflex) – a short tube and a ‘port’, usually front or back, allows the bass driver to breathe a bit easier but poorly designed ones honk and sound quite unnatural.
3. Transmission line – A large long ‘line’ (tapered tube), traditionally lined with wool to remove HF, allows the bass driver to breathe easily and the ‘line’ reinforces the bass at the normal roll-off point. This allows for an extremely natural sound which, to me, is the most realistic except for ‘panel speakers’ – see below. Their forte is a tuneful, un-forced bass often going very low for the size of box involved.
4. Horn speakers – which are basically small drivers with a megaphone in front. They can sound great but the frequency response is usually not very even.
5. Open baffle - drivers just mounted on a board. These can sound very natural but you need a huge board or mount the speakers in a wall between rooms.

'Panel' speakers are just flat panels, typically 2-3" thick. They use an extremely thin and lightweight sheet of plastic, rather like a drum skin, which is moved precisely by a varying electrostatic field. Because the sheet is so light, it moves easily and fine detail can be resolved. You can hear more fine detail with panel speakers than pretty well any ‘normal’ electromagnet/piston speakers. Another big advantage is that all of the sound appears to come from one point of origin in the centre of the panel so they are able to recreate a very precise audio ‘image’ of the orchestra etc. Imaging is something which headphone listeners will barely be aware of but imaging and dynamics are essential for realism in my opinion. Panel speakers are often regarded as the most accurate speakers but some are certainly a bit compromised on bass. You really do owe it to yourself to listen to some before you spend your money. They are a revelation to most people but often prohibitively expensive. Try to hear some Magneplanar 12s; you can find these for about £1,200 and at that price they really are an absolute bargain. My speakers were three times the price and in many ways they are not as good as the Magneplanar 12s. Audition them!

You MUST however use a good amplifier. Not necessarily an expensive amp – but a good one. The Magneplanars, and indeed most panel speakers will reveal any faults in the source and the amp; that is part of the frustration of building a superb audio system – but it’s worth it. To start with, audition your speakers with the best equipment and cable possible – and then try to compromise downwards. You usually can.

As for your last question, I use PMC OB1i speakers (transmission line), Bryston 4BSST power amp (300w), Bryston BP26 pre-amp, Benchmark DAC1 and for sources I use either a Sonos (do NOT use their volume control), Squeezebox Touch (ditto), Technics FM tuner or a Panasonic Blu-ray player if I really need to spin a CD. Speaker wires are good old (and cheap) Linn LK20 and interconnects are (mainly) balanced Chords.

I won’t go into the differences between varying amplifier designs in this post but there are similar issues of which you should be aware before digging too deep in your pocket. You can waste an awful lot of money on pretty well useless amps if you are not careful.

[Dave2002]

Nevalti

I think the better designs of what you call ported speakers are in fact bass reflex speakers, which if well designed can enhance the bass response down towards the driver resonance frequency, below which there is a sharp drop in response. They don't have to be boomy or honk. They probably have better sensitivity in the low frequency ranges. One explanation of how they work is to note that the air movement from the rear of the speaker is out of phase with the movement at the front. By using a ported design, the air movement through the port is phase reversed, so that it reinforces the moving air from the front of the speaker. IIRC check out Helmholtz resonators.

Some other designs achieve a relatively flat response by damping a lot of the energy, but that reduces their efficiency. Transmission line speakers also can be good. Check out the theory of electrical transmission lines, and then compare with the mechanical model which such speakers presumably correspond to.

Horn speakers manage to get high efficiency, because of good mechanical impedance matching between the driver and the air being moved. Hardly anyone uses them now. There used to be some commercial cabinet designs (e.g Klipsch) which used relatively weak approximations to a good horn, but they tended to be very large. Large cabinets are pretty much out of favour now.

[Nevalti]

Nevalti

I think the better designs of what you call ported speakers are in fact bass reflex speakers, which if well designed can enhance the bass response down towards the driver resonance frequency, below which there is a sharp drop in response. They don't have to be boomy or honk. They probably have better sensitivity in the low frequency ranges. One explanation of how they work is to note that the air movement from the rear of the speaker is out of phase with the movement at the front. By using a ported design, the air movement through the port is phase reversed, so that it reinforces the moving air from the front of the speaker. IIRC check out Helmholtz resonators.

Some other designs achieve a relatively flat response by damping a lot of the energy, but that reduces their efficiency. Transmission line speakers also can be good. Check out the theory of electrical transmission lines, and then compare with the mechanical model which such speakers presumably correspond to.

Horn speakers manage to get high efficiency, because of good mechanical impedance matching between the driver and the air being moved. Hardly anyone uses them now. There used to be some commercial cabinet designs (e.g Klipsch) which used relatively weak approximations to a good horn, but they tended to be very large. Large cabinets are pretty much out of favour now.

In fairness, I did say 'poorly designed ones honk'. As well as the multitude of poor or mediocre bass reflex speakers in hundreds of show-rooms, there are indeed many excellent ones and I am sure some people will prefer them over my preference for transmission line and panel speakers. I suspect if I was interested in thumping bass pop music I would find them more attractive. I tried to be impartial in my comments but I obviously have my preferences - same as others have theirs.

As for the theory behind the designs, it is often not carried over into practice very well so I try not to be influenced too much by theory. Although I have ended up with fairly mainstream 'professional' equipment, I really did get there by listening - over many years (I bought my first 'proper' hifi 50 years ago). My practice has always been to go to a live concert, then audition equipment playing the same performance and try to get as close to live sound as possible.

I'm not sure what you mean by 'large cabinets'. It seems pointless to me putting a small speaker on a stand when you can have a much taller floor standing speaker without taking up any more space and almost invariably offering better bass performance. The 'large' cabinet must, of course, be solidly constructed to stop the box resonating. Try listening to a pair of huge, 25 year old TDL Reference speakers and see if you think they should have fallen out of favour.... or, not quite so impressive, the big old KEF Reference speakers, or even the seriously flawed Linn Isobariks. You don't NEED large speakers to get quality sound but it certainly helps. Unfortunately you simply can not get natural sounding bass out of small boxes nor indeed small panels.

Having said that, when I eventually end up in an old-folks home, I will happily listen to little LS3/5As fed by a Bantam Gold - or similar.

[Dave2002]

In fairness, I did say 'poorly designed ones honk'. As well as the multitude of poor or mediocre bass reflex speakers in hundreds of show-rooms, there are indeed many excellent ones and I am sure some people will prefer them over my preference for transmission line and panel speakers. I suspect if I was interested in thumping bass pop music I would find them more attractive. I tried to be impartial in my comments but I obviously have my preferences - same as others have theirs.

As for the theory behind the designs, it is often not carried over into practice very well so I try not to be influenced too much by theory. Although I have ended up with fairly mainstream 'professional' equipment, I really did get there by listening - over many years (I bought my first 'proper' hifi 50 years ago). My practice has always been to go to a live concert, then audition equipment playing the same performance and try to get as close to live sound as possible.

I'm not sure what you mean by 'large cabinets'. It seems pointless to me putting a small speaker on a stand when you can have a much taller floor standing speaker without taking up any more space and almost invariably offering better bass performance. The 'large' cabinet must, of course, be solidly constructed to stop the box resonating. Try listening to a pair of huge, 25 year old TDL Reference speakers and see if you think they should have fallen out of favour.... or, not quite so impressive, the big old KEF Reference speakers, or even the seriously flawed Linn Isobariks. You don't NEED large speakers to get quality sound but it certainly helps. Unfortunately you simply can not get natural sounding bass out of small boxes nor indeed small panels.

Having said that, when I eventually end up in an old-folks home, I will happily listen to little LS3/5As fed by a Bantam Gold - or similar.

I think the Klipsch horn cabinets were bigger than the TDLs and the others you mention.

By the time you get there you might need big speakers with the volume turned up high in an old-folks home, though probably the staff would switch you over to radio 1 or 2, local radio, or worse! Agggghhhhh!

[PJPJ]

By the time you get there you might need big speakers with the volume turned up high in an old-folks home, though probably the staff would switch you ........

.....off.

[Nevalti]

.....I have found that the effect of these resonances can be mediated by leaving the living room door to the hall open by about 45 degrees and the sliding doors into the dining room part open too when they seem to act as crude untuned bass traps!! It is not perfect and not scientific either but it does take the sting out of room resonance. I haven't tried the effect of opening windows for the obvious reason.........

I do agree that leaving a door open can dramatically alter the sound, usually for the better.

My speakers are each side of French windows with two doors and two side windows. If I open those two doors and windows, the audio image expands backwards onto my patio and you can very clearly 'see' the front to back positioning of the orchestra as well as the left to right positions. Fortunately I live at the end of a lane with only one neighbour so I can enjoy this 3D sound image every time they are away or at work.

I have never heard anyone else refer to this open door phenomenon but I presume that if I had a big enough room I would get this very clear 3D imaging within the room. Moving the speakers 10 ft from the back wall is not domestically practical.