The Driver/Enclosure relationship

[Geoff.R.G]

I think there it is important to know what definitely doesn't work, and I think there is probably some consensus on this, as well as what appears to work. Beyond that only listening will have any real effect on what happens next.

I am fairly convinced that chipboard, fibre board and the like aren't particularly suitable cabinet materials in the generally available thicknesses. However the required thickness may be affected by the size (longest dimension) of the panels because large, thin panels can pant. That said many a PA speaker has either a chipboard or plastic enclosure but in that application the speaker is part of the sound, in Hi-Fi the speaker isn't intended to comment.

If you are building your own speakers you can do what pleases you, building commercially is a different matter.

[Lindsayt]

I don't agree that the driver is the most important part of a speaker. I think all aspects have equal weighting. The drivers that RD chose for the cube speakers are perfectly fine andcheap. Once doped sympathetically nobody should require anything more expensive. I bought a load of the 5.5 " drivers for less than £10 each. Maybe they become crude sounding when driven hard but if you don't ask too much from them then it's happy days.

Quality of driver is not directly related to cost.

I've heard NVA speakers in a bake off against Steve57's red and black DIY'd speakers.
In that conext I wouldn't describe NVA speakers as "perfectly fine".
I'd describe NVA speakers as good sound for money and good sound for the size. They are not world class speakers. Steve57's are.

So what differentiates a World Class speaker from a good speaker?

What is the most differentiating factor?
Crossover? I don't think so.
Cabinet? It's easy to have a pleasantly over engineered cabinet when going DIY for sensible money.
Cabinet design? Yes that's of some importance - in the bass. Less important for the midrange and treble.
Internal wadding or the lack of it? That's something that's easy to get right - or to get right enough.
What else?

Driver quality - of course!

When going DIY, you can either aim for great sound quality for the money - eg SteveTheShadows really nice single driver speakers.
Or you can aim for World Class speakers, - EG Steve57's red and black speakers which are also great sound quality for the price he spent on putting them together, but they did cost him rather more than SteveTheShadow's speakers.

[SteveTheShadow]

You have to decide what you are designing your speakers to do. Are you designing them to listen to music through or are you designing them have a flat frequency response in an anechoic chamber?
Once we get it through our head that accuracy is not possible with a loudspeaker, then we’re getting somewhere and can let our creativity run the show.

One of the advantages of a DIY loudspeaker is that we can tweak it to work in our own particular room. The mantra for a DIY speaker, is that we design it to fit the room, not the other way ‘round. We can leave the room treatments and bass traps to the commercial and studio sector, where they belong.

Commercial makers cannot cater for the room in which their product is going to be placed, so they tend to force the end user into putting the bloody things in the middle of the room, otherwise they boom like buggery. It is up to the dealer to sell the punter a speaker that works in its destination environment, and in the room placement that the punter wants it. How many are prepared to do that?

To me, WAF is not so much about the appearance/size of a speaker, rather it is about the speaker itself, not dominating the domestic environment. My Fanes are certainly not small by modern standards, but they blend into the room. Steve57s even bigger speakers, do the same. This is because are designed to be placed against a wall. WAF is all about back-to-wall placement, not about tall, thin multiple driver speakers that boom unless placed 1m from the side and back walls. What a complete load of utter bollocks that is! And yet most ‘bought’ speakers demand such a room placement, and they wonder why the hi-fi market is on its knees!

All of which brings me neatly back to the enclosures themselves. Basically, if you want speakers to work next to walls, you want either sealed boxes or transmission lines. These roll of at the bottom end in a shallower, more even manner than ported speakers. This can easily be turned to the builder’s advantage as the wall placement will compensate for the roll-off, giving a nice deep, even quality to the bass. My Fanes will do 30Hz, no bother when placed next to a wall. Take them to a bake off such as Owston and they become bass light and strident, because the circumstances don’t allow wall placement. Conversely, open baffles work superbly in that room, but are a nightmare in a small domestic room as they need space behind them; ruling them out at a stroke for most people.

Now I wont do anything other than sealed in my own room. As ever YMMV but I’ve been at it for nearly 50 years now and have never heard a bad sealed speaker. OTOH I’ve never heard a ported speaker in my own place, or at a show, sound like anything other than overblown shite.

The only domestic ported speakers I’ve ever had time for have been the long gone, World Audio Design KLS III and their smaller Aperiodic design which was done by Peter Comeau.

[Daniel Quinn]

What drive units did ste57 use. Also what cabinets.

[SteveTheShadow]

What drive units did ste57 use. Also what cabinets.

I think he has 18” Fane Colossus bass drivers; two per cabinet in a V formation, plus a 12” midrange (don’t know which) and a horn loaded Heil Air Motion Transformer treble unit; again, I can’t think of the manufacturer offhand.

The cabs are in two sections and open backed, with up firing rectangular cross section pipes off the mid and bass cabs, that exit at the top of the cabinet. The bass units are in their own open backed cab and serve as solid platforms for the midrange/ treble enclosures.

They are a hybrid of a transmission line and an open baffle. Nobody else to my knowledge has done this. Not recently anyway. They work next to walls because of the rear radiation from the bass and mid baffles, being heavily damped out the back and some of it being redirected at the ceiling via the pipes. They’re unique.

[Latteman]

RD's speaker design principles are / were a game changer for me . Nothing else had such a dramatic effect on me. I think those principles can be used, tweaked and expanded on for one's own ends.

I don't tend to agree with spending lots on drivers (or anything for that matter). As far as the cheap Chinese kevlar drivers go i truly believe they are perfectly acceptable compared to other drivers i have heard. I listened to some of the 5.25" mid bass (as found in the cube 3 design) straight out of their box and with no filters I immensely enjoyed it, the only fault i could level at them was they were a bit strident up top . A couple of coats of plastidip cured them of this with no obvious drawbacks. When it came to blending them with the tweeters i had to add some bisonkit but not much.

When i doubled up the number of mid bass drivers the reduction in distortion was remarkable. When married to isobaric 12 inchers (cheap chinese model picked by RD) and five tweeters per channel i thought i had reached heaven. Running them with no filters (crossover) is also very important.

I am not remotely interested in pin point imaging or table top frequency response flatness. That is probably why i like what i like. The way i have multiple drivers facing in all directions means i get a wall of sound effect

What makes a world class speaker for you Lindsay ? And would it be the same for me ?

[Daniel Quinn]

I'd be interested to know as well. Dumping the crossover and rigid speaker enclosures were a game changer for me.

[Lindsayt]

A world class speaker is one that sounds about as good as any speaker ever made. Give or take a little bit.
One where there might be better speakers in certain respects. But one where there are no known speakers that are a combination of as good as and better in every important sonic respect.

World class speakers have a way of turning listening to them into enjoyable events that poor to mediocre to good speakers can't match. Relatively speaking.

Or you could simply use Steve57's speakers as a benchmark. If a speaker sounds about as good as his it's World Class.

[jimbob]

Lindsay,

Any links to these speakers built by Steve57? I’ve done a google search but couldn’t find them! Ta!

[savvypaul]

I've heard NVA speakers in a bake off against Steve57's red and black DIY'd speakers.
In that conext I wouldn't describe NVA speakers as "perfectly fine".
I'd describe NVA speakers as good sound for money and good sound for the size. They are not world class speakers. Steve57's are.

They were my Cube 1s. They ran out of puff pretty quickly in that very large room. Didn't sound anywhere near as good as they do in my front room. Richard determined at that event to make a set of Cubes with 12" drivers, hence the BB Cubes.

Steve57's speakers were excellent. They had immediacy and clarity without sacrificing any of the tone and timbre that music uses to melt your heart. They worked on an emotional level and an intellectual level. They sounded completely natural. Couldn't fault them.

Right at the end (I think you and most others had already left) Nick plugged his 300b monos in to those £75k Maxonics, and that was a big improvement on what we heard from them first up.