General Forum

Re: Penta Speakers

Christian — Wed, 11 Jun 2008 07:48:43 GMT

Alex:
camshaft:

Either way, are you trying to say that the 8000's are superior speakers to penta 3's?
Austin

Not at all - I'm merely saying that more drivers doesn't = better sound, it just = more sound.

Four bass drivers in the Penta make it possible to produce a deeper sound. You could argue that one Penta woofer can produce sound in the 20-40 Hz range, but the sound would be very low. Having 4 bass drivers makes the Penta able to produce a high level of sound in the 40-50 Hz region. So yes more drives = more sound, but if more sound = more hearable deep bass, then more drivers = better sound also.

IIRC the woofer in Bl5 could be replaced by 70.000 of the BL5 tweeters. Placing them in the cabinet would be hard though.

Re: Penta Speakers

Alex — Tue, 10 Jun 2008 15:37:58 GMT

camshaft:
Either way, are you trying to say that the 8000's are superior speakers to penta 3's?
Austin

Not at all - I'm merely saying that more drivers doesn't = better sound, it just = more sound.

Re: Penta Speakers

Puncher — Tue, 10 Jun 2008 14:09:11 GMT

I'm not sure how much of this is strictly correct - a true speaker array is much more of a science that just lumping drivers next to each other. The array can be driven in a way that can dynamically focus a "beam" of sound rather than, would seem likely, scatter it to the four winds. I believe that, correctly driven, they can compensate for and cancel expected nulls in the frequency response, there are many patents in this area - I'm sure Dave Moulten could offer an interesting perspective on the merits of an array solution (and how it differs from just adjacent speakers driven with an identical signal).

Re: Penta Speakers

Alex — Tue, 10 Jun 2008 13:58:29 GMT

ben12345:
Alex:

Multiple tweeters are not beneficial, and the same goes for multiple midrange drivers. If anything, you make the sound worse by using multiple drivers if you listen on varying vertical axis. Sound from each driver will overlap and you'll get destructive and constructive interference leading to comb filtering and phasing issues.
The only way round it is to have as few sources of sound as possible.

I'm sure these speakers sound terrible then;
http://junkies.wordpress.com/2007/02/13/mcintosh-xrt2k-loudspeaker-system/
Saying that, i'd probably have these over anything B&O have produced, and are currently producing!

Actually they do! As lovely as McIntosh stuff is (particularly their amplifiers), their loudspeakers IMO leave a LOT to be desired. The idea behind that many drivers is to increase the size of the soundstage, which while it sounds like a good idea, a single set of high quality drivers positioned further apart (BeoLab 1s are an example) or with controlled dispersion (BeoLab 5s being the ultimate example) will give you the same kind of size to the soundstage, but without all the lumpy response (the McIntosh amps are renown for producing an amazingly flat and clean signal) and 'flittering' hi-end.

A much smarter solution to the problem McIntosh are trying to tackle would be... electrostatic speakers?

Either way, one bi-product of both of these solutions is that the sound would carry better than a conventional speaker (if they were compared at the same volume), which is more of a bad thing in a conventional listening environment as this would massively increase the amount of room reflections you hear (something the Acoustic Lens does a brilliant job of tackling).

Re: Penta Speakers

camshaft — Tue, 10 Jun 2008 13:56:07 GMT

Alex:

Multiple tweeters are not beneficial, and the same goes for multiple midrange drivers. If anything, you make the sound worse by using multiple drivers if you listen on varying vertical axis. Sound from each driver will overlap and you'll get destructive and constructive interference leading to comb filtering and phasing issues.
The only way round it is to have as few sources of sound as possible.

But Alex, how often do you listen to speakers on a varying vertical axis? If you're actually going to try to make an argument over varying vertical axes, then you'd have to hold it against the ALT lensing speakers too, as those lenses assume that the ear will be relatively close to their vertical height, and not 30 degrees above. The interference and overlap argument may hold true for higher frequencies; I'm not sure as I've never bothered to calculate it, but either way, look at how closely together the mid range units are spaced on the Pentas. They're close enough that there's no meaningful degenerative effect from the vertical spacing. Regardless, rather than trying to argue what would happen to the waves, look at the frequency response plots of high end speakers using linear arrays. Did you look at the site that I posted the link to earlier? Look at how flat a frequency response Zaph got out of two "budget" drivers spaced vertically.

Either way, are you trying to say that the 8000's are superior speakers to penta 3's?

Austin

Re: Penta Speakers

Medogsfat — Tue, 10 Jun 2008 13:06:00 GMT

Good idea - I can easily supply my stunning MC120.2's if needs be, Id be interested to see (hear) how they compare to the MS150's which are going to be my next project when I manage to track a pair of old dogs at the right price

A quick backtrack to the OP. IMO penta's are easily the best pound for pound speakers on the market at current values.

Chris.

Re: Penta Speakers

Christian — Tue, 10 Jun 2008 12:25:59 GMT

I too would be interested, but I need some notice to plan the trip...

Re: Penta Speakers

j0hnbarker — Tue, 10 Jun 2008 07:11:09 GMT

Scotch Corner perhaps?

Re: Penta Speakers

Puncher — Tue, 10 Jun 2008 05:15:34 GMT

We could do it on the roadside of the A1, easy for everybody - I can bring a generator (plus there'll be no walls/corners to worry about)

Seriously, it would be great if we could organise something (and have a bit of a jolly afterwards)

Re: Penta Speakers

Peter — Tue, 10 Jun 2008 04:47:18 GMT

I agree that another shoot out would be good. This time I would suggest that we use passive speakers as well as active - and maybe set them up better. I do have some MS150s available as well as M100s and once my Beomaster 4401 is ready, we will have a nice amplifier to use. Venue will be an issue.

Re: Penta Speakers

j0hnbarker — Tue, 10 Jun 2008 04:16:55 GMT

Puncher:

I take it you have read this speaker shootout - written, by our recent birthday boy, at the time of the release of the BL9.
It would be cool to do this again while also plotting the decline in the ability to determine the difference versus the amount of alcohol consumed

I remember it well. Would be good to try this again sometime, but I guess the logistics would be difficult to sort out!

Re: Penta Speakers

Puncher — Tue, 10 Jun 2008 03:42:14 GMT

I take it you have read this speaker shootout - written, by our recent birthday boy, at the time of the release of the BL9.

It would be cool to do this again while also plotting the decline in the ability to determine the difference versus the amount of alcohol consumed

Re: Penta Speakers

j0hnbarker — Tue, 10 Jun 2008 03:24:41 GMT

Llewelyn:

I have to agree - A blind test would be interesting! Regarding Pentas, I once had a setup involving the following:
Beomaster 8000, Beogram 8002 (MMC2), Beogram CDX and passive Pentas. It sounded unbelieveable! Far better than active Pentas and definately without question better than the BC2300/Lab 8000s I replaced it with!

Got to agree with you. My living room setup is Beomaster 8000, Beogram 4002, Beogram CDX, and Beovox Pentas. This setup sounds better than any combination of source I have heard with Beolab 8000s.

Re: Penta Speakers

Puncher — Tue, 10 Jun 2008 03:00:57 GMT

The issue isn't "active or not", in the case of the BL8000's the issue is the level of performance that can be dragged out of a limited volume enclosure, using a pair of small, albeit long-throw, drivers. Certainly being active definitely helps in this case as the bass power to the drivers is considerably boosted to extend the apparent bass extension of the speakers as a whole. (For bass read "air volume moved").

Active speakers have the distinct advantage of an amplifier for each driver and therefore the combined response can be specifcally tuned (with active, i.e. signal level, components) to achieve the desired, optimal response. Passive amplifiers have to supply all of the power, through a passive crossover, to all of the drivers. While the passive solution can sound wonderful, and was the basis of all hifi before the '80's, I would think it is obvious that separate optimally matched active amplifiers, separately powering the same drivers in the same enclosure can at least match if not likely exceed the performance of the passive solution. The reverse may not be true - how good could a pair of passive BL3's sound? - it would be interesting to find out.

I think in B&O's case, they took advantage of the technical possibilities and used them to do previously impossible things with the shape and styling of the speaker enclosures rather than persue ultimate performance with the early active speakers, hence the BL8000's.

The Lab 9 and Lab 5 show what is possible using active speakers (the Lab 5 also using DSP to modify the "crossover" to achieve it's bass equalisation). As clever as the ALT is, it's purpose is to modify and control the "directionality" of the treble output, it is not really a function of being active or not.

Re: Penta Speakers

wirralsimon — Tue, 10 Jun 2008 02:34:32 GMT

Interesting debate: This thread got unexpectedly revivied a few days ago and has been playing around in my head ever since: 8000 vs Redline Whilst no sane person would argue that the Redlines look as good as the 8000's the fact that there was nobody at all disputing the fact that the redlines sounded better does make me question the whole concept of active speakers. With the possible exception of the ALT speakers do any of the B&O active speakers actually sound better than the higher-end B&O passive speakers? On the same lines what are the acoustic (rather than ergonomic) considerations that make active speakers better?

Simon