Identifying Legitimately High Fidelity Loudspeakers: Myths & Facts about Cabinets

[agarwalro]

From the article, Myth #4's editorial Note by Philip Bamberg,

there is also a myth that one can adjust the detail of their monitor speaker by adding or removing stuffing from inside the box. Never remove stuffing! If the audiophile needs something to tweak, he needs to look elsewhere. Any increase in “detail” he hears with less stuffing is truly an increase in the colored interior box sound, and not more signal detail.

How does the Salk SS's or DM Phil's open back midrange (user selects quantity of damping to be used) design philosophy reconcile with this statement. In fact, on the face of it, Salk/DM design seems to be contradictory . So, what am I missing?

 

[Dennis Murphy]

From the article, Myth #4's editorial Note by Philip Bamberg,


How does the Salk SS's or DM Phil's open back midrange (user selects quantity of damping to be used) design philosophy reconcile with this statement. In fact, on the face of it, Salk/DM design seems to be contradictory . So, what am I missing?

The context for the quote is a closed box, where presumably the amount of stuffing used is considered optimal by the designer. Both the Salk and Philharmonic cabinets are lined with foam to reduce reflections from the side walls. The stuffing is used purely to control the amount of rear wave transmission out the back. There is no single optimimal amount of fill, because it will depend on where the speaker is located, the program material, and individual taste.

 

[gene]

Guys;

I am adding this image and text to the article.

This is a new subwoofer RBH is working on for their Status Acoustics Line which I will be reviewing personally.

RBH Sound new cost no object Status Acoustics line of speakers feature a layered acoustically inert enclosure construction. This method of construction involves bonding multiple layers of materials together and allows the wall thickness of the enclosure to be varied without the limits imposed by more traditional panel construction. When needed, bracing for the enclosure is integrated into the layered design. The end result is an enclosure that is extremely acoustically inert. Doing this also allows the manufacturer more ability to shape the cabinet design to their liking. There are some downsides prohibiting this type of construction for most manufacturers. It involves a very costly process that uses a lot of materials to produce and it results in a very heavy cabinet which is expensive to ship.

 

[agarwalro]

The context for the quote is a closed box, where presumably the amount of stuffing used is considered optimal by the designer. Both the Salk and Philharmonic cabinets are lined with foam to reduce reflections from the side walls. The stuffing is used purely to control the amount of rear wave transmission out the back. There is no single optimimal amount of fill, because it will depend on where the speaker is located, the program material, and individual taste.

That makes sense and thank you for the clarification.

Edit added - So, the assumption is that the cabinet design and lining for reflection damping sufficiently damps the box too?

 

[scott911]

that's good stuff. Years ago when I worked my way through engineering school, I worked at a local hifi shop. I used to bench test amps for customers prior to installing them at their place. I also would routinely show them internals of loudspeakers by popping out woofers of the floor models. They loved it and it gave them an appreciation for good engineering. This seems to be lost today in a sea of psuedo science and dumbing down the public that good parts aren't needed for good sound....

not us audioholics! ... you keep us thinking and questioning. Many Thanks Gene & company.

 

[goldstarsteve]

Thin walled cabinets

What about thin walled cabinets used in classic BBC monitor style speakers such as Harbeths ?

 

[farrow099]

Just to clarify; I don't actually buy much of anything from best buy.
When I do, I always end up returning it!

I'm 27yrs old and I've owned so many speakers that I have trouble remembering them all!

In fact my EMP Impression series are on Ebay right now because I jumped onboard the Aperion train!

I think I went from Aura multimedia speakers, to Creative Labs multimedia speakers, to Klipsch Promedia, then Klipsch towers, followed by Axiom m3s, axiom m22s, svs cylinder sub, Klipsch quintet, klipsch icon, premier accoustech titanium line, polk rti line, klipsch reference iv line, emp f series, klipsch reference iv series II, emp impression, and now aperion verus grand! (verus btw is latin for "the true")

Mix in a dozen receivers, half dozen subs, and dozen car audio systems and you have a general idea that I am an audioholic!

 

[lsiberian]

http://total-insulation.com.au/pdf/Rockwool-Accoustical-Properties.pdf

Long haired wool has the reputation as being the best material of all, but is price prohibitive. Best bang for the buck is still fiberglass in my opinion. I've tested JUTE, which looks like Rockwool, but do not see it for sale many places. If you have a source in the USA, go ahead and share it here. Thanks.

http://www.bobgolds.com/AbsorptionCoefficients.htm

Is the most comprehensive list I know of. Please keep in mind differences less than 0.15 are considered insignificant. So 0.85 or higher is pretty much golden.

As far as I'm aware mineral wool is much cheaper than high density fiber. It does however require more support than high density fiber so many companies prefer high density fiber. 4" of AFB is actually sufficient.

Roxul Acoustical Fire Batts Mineral Wool 2 inch Case of 6 is a very high price for the stuff, but a great source if you need only a single sheet. You simply double up the sheets to get 4". In either case make sure you cover the material with burlap or grill cloth to be sure you keep fibers out of your drivers.

Welcome to SPI - Specialty Products & Insulation Co.
is supposed to be significantly cheaper and would probably be a better option for a small speaker manufacturer.

There is certainly nothing wrong with using high density fiber. And if you have a better price point on it then by all means get it.

I'm not familiar with the Australian market for rockwool.

 

[MinusTheBear]

Anyone else receive Axioms newsletter this month?

 

[AcuDefTechGuy]

RBH Sound new cost no object Status Acoustics line of speakers feature a layered acoustically inert enclosure construction. This method of construction involves bonding multiple layers of materials together and allows the wall thickness of the enclosure to be varied without the limits imposed by more traditional panel construction.

Is that like the Revel Salon2's 9-layer MDF, 2.5 inch thick cabinet wall?

 

[highfigh]

Hopefully this doesn't start an arguement, but I recently purchased a set of Arx A1s and A2 center, replacing my Axioms. I've always been a fan of Axiom, but now comparing the cabinets to the Arx the Axioms are not a solid and seem to echo with the knock test compared to the Arx. I compared the A1 bookshelf to the Axiom M2 and M22 and its not even fair the A1 weighs almost as much as the M22 and out weighs the M2 by 4-5lbs, to me thats a lot considering its a 5.25" bookshelf.

Reading this article the EP600 subwoofer kept coming to mind, its a 47" tall cabinet with no or next to zero bracing, but yet they want close to $2k for it. I posted on their forum and couldn't get an answer why Axioms subs are so much more compared to the other brands. For example the EP600 vs the SVS PB12+, the SVS out performed the Axiom in every test sound wise. The SVS has a better built cabinet, more powerful amp, and a slightly beefier driver thats also handmade just like Axioms, but yet Axiom charges $500-600 dollars more than the SVS. So my question to them was what factor causes Axiom to charge such a premium compared to the other brands?

What kind of finish is on each? If one is vinyl covered and the other is lacquered veneer or high gloss, like a piano, there's your answer. One takes no extra time to get the end result and the other is very time consuming. This is a moot point if the cabinets were made in Asia. OTOH, the difference may come from the cost of the drivers and crossover components.

 

[highfigh]

that's good stuff. Years ago when I worked my way through engineering school, I worked at a local hifi shop. I used to bench test amps for customers prior to installing them at their place. I also would routinely show them internals of loudspeakers by popping out woofers of the floor models. They loved it and it gave them an appreciation for good engineering. This seems to be lost today in a sea of psuedo science and dumbing down the public that good parts aren't needed for good sound....

When I started in this business, I was working at a small store and if we needed to repair speakers, we did it on the counter in the storefront, not the back room (unless the speakers were really large, then it was easier to leave them back there). The vast majority were brands that came from other dealers and some were just complete crap. One brand was called Omega, from Shaak Electronics. We came up with a replacement set of drivers and pre-made crossovers that sounded pretty decent for the price and we'd re-load about 3 sets every week, usually after the kids would have a big party. If someone could afford better speakers, we'd take them in that direction but for the teen-aged kids, these were a good, low-cost alternative. We educated a lot of kids about why one thing was better than another and they became good customers, even though the store owner would usually tell us that we should help another customer or do other things because "they're not going to buy anything- stop wasting time". 25-30 years later, many of them still have some of the equipment they bought back then and a few actually worked in the audio business.

 

[gtpsuper24]

What kind of finish is on each? If one is vinyl covered and the other is lacquered veneer or high gloss, like a piano, there's your answer. One takes no extra time to get the end result and the other is very time consuming. This is a moot point if the cabinets were made in Asia. OTOH, the difference may come from the cost of the drivers and crossover components.

Both Arx and Axiom has almost the same black "oak" type veneer. Not sure what you mean by "One takes no extra time to get the end result and the other is very time consuming"? I will try and post some pictures comparing the two the veneers are almost identical, the Arx's black "oak" seems a little less natural looking than the Axiom. The woofers are not even close Axioms only measures 4.25" from outer surround going across. The Arx measures 5.25-5.5" across starting from outer surrounds, but both start that they are 5.25". The baskets aren't even in the same league the Axioms use stamp baskets and are tiny, the Arx use cast metal basket with a huge magnet, that looks like a small subwoofer. That could be why the Arx weights more because of that magnet who knows but I might take them apart and check everything out in more detail.

I've always liked Axioms and I still do but I think I like the Arx better.

DISCLAIMER: This is totally subjective, these are my opinions on which sounds better to my ears. I'm not "pushing" "promoting" or "recommending" either brand, I read the article and though I'd give my opinion on my speakers I have since I can do a direct comparison between two similar priced ID bookshelfs.

 

[highfigh]

Both Arx and Axiom has almost the same black "oak" type veneer. Not sure what you mean by "One takes no extra time to get the end result and the other is very time consuming"? I will try and post some pictures comparing the two the veneers are almost identical, the Arx's black "oak" seems a little less natural looking than the Axiom. The woofers are not even close Axioms only measures 4.25" from outer surround going across. The Arx measures 5.25-5.5" across starting from outer surrounds, but both start that they are 5.25". The baskets aren't even in the same league the Axioms use stamp baskets and are tiny, the Arx use cast metal basket with a huge magnet, that looks like a small subwoofer. That could be why the Arx weights more because of that magnet who knows but I might take them apart and check everything out in more detail.

I've always liked Axioms and I still do but I think I like the Arx better.

DISCLAIMER: This is totally subjective, these are my opinions on which sounds better to my ears. I'm not "pushing" "promoting" or "recommending" either brand, I read the article and though I'd give my opinion on my speakers I have since I can do a direct comparison between two similar priced ID bookshelfs.

I didn't mean these are necessarily like my example- I was generalizing and was referring to vinyl laminate or in some cases, wood veneer vs lacqured or painted cabinetes. If a speaker has veneered substrate with real wood corners, making the cabinets can be a very quick process but if they have a finish with many coats with sanding/polishing, etc- it can take a long time. Also, since some finishes take a fair amount of time to cure/harden, that will delay shipping. Items that sit in the warehouse cost the company money, so they need to sell for more.

I went to one of my distributors for an open house and one of the vendors had a speaker that had been cut in half- across the width, to show a cross-section of the cabinet. I wasn't impressed, even though it's a name brand that has had quite a bit of success. While it's probably pretty strong, it wasn't the most inert cabinet I have knocked on even though the sides are curved.

 

[gene]

Is that like the Revel Salon2's 9-layer MDF, 2.5 inch thick cabinet wall?

The RBH cabinet construction goes well beyond anything that Revel is doing which doesn't imply its necessarily audibly better. The RBH approach is borderline insane IMO. The sub alone weighs in at over 200lbs. We shall see if all the bracing paid off. I loath the idea of moving those boxes around during the review and setup process.

 

[gene]

Anyone else receive Axioms newsletter this month?

no please post it here if you can.

Update, I found it:
October 2011

All I can say is WOW. More fun tomorrow on this

 

[GranteedEV]

The sub alone weighs in at over 200lbs.

So does my sub, and I feel it was a half-assed build job

Actually, from the pics of the RBH sub above, wouldn't it weigh like, way more than 400lbs? My sub uses 2 sheets of 3/4" MDF (plus a bit of oak ply and 1/8" MDF here and there). The RBH looks like 1" MDF and more of it, too.

 

[gene]

So does my sub, and I feel it was a half-assed build job

Actually, from the pics of the RBH sub above, wouldn't it weigh like, way more than 400lbs?

Nice job! Better not show Axiom that cabinet though else they will tell you it caused more audible distortion with the bracing

Perhaps the RBH cabinet weighs 200lbs without the drivers. I don't recall but we shall see.

 

[AcuDefTechGuy]

The RBH cabinet construction goes well beyond anything that Revel is doing which doesn't imply its necessarily audibly better. The RBH approach is borderline insane IMO. The sub alone weighs in at over 200lbs. We shall see if all the bracing paid off. I loath the idea of moving those boxes around during the review and setup process.

Do you think even better than the 800D's cabinet?

From the Stereophile measurements, the 800D cabinet is virtually resonance free.

But as you say, cabinet alone doesn't guarantee better sound performance.

 

[gene]

Do you think even better than the 800D's cabinet?

From the Stereophile measurements, the 800D cabinet is virtually resonance free.

But as you say, cabinet alone doesn't guarantee better sound performance.

No way of determining that by just looking at the pics. I think the 800D is a fine piece of engineering but it goes against all the principles that Axiom preaches so what do I know?

In all seriousness, basic mechanics is when you add more bracing, you raise the resonance frequency but it also lowers its amplitude, NOT raises it. The science is pretty well established on this so the fact that its even being debated is quite odd.

The only conceivable way I can see it raising it is if Axiom didn't cross coupling the braces and simply added mass rather than rigidity. They are a lone wolf in this believe as all the major quality loudspeaker companies I know try to produce the most rigid and inert enclosure possible. Most DIY loudspeaker builders also do the same. Paradigm, Revel, B&W, RBH, Snell, etc all make very rigid enclosures but their speakers are often costly and heavy.