3-way active dedicated stereo listening

Guiria

Guiria

Senior Audioholic
I've been using Sketchup to draw some triangular style designs and I have to admit that thinking about building a triangular style speaker has me second-guessing going that route. I realize the primary benefit of a prism style design is that there would be no parallel edges thus decreasing internal reflections that would otherwise cause resonance. Several quality loudspeakers are built as a rectangular box so the question is...

How big a difference in SQ would the prism style speaker have over a standard box speaker?
 
Pogre

Pogre

Audioholic Warlord
I've been using Sketchup to draw some triangular style designs and I have to admit that thinking about building a triangular style speaker has me second-guessing going that route. I realize the primary benefit of a prism style design is that there would be no parallel edges thus decreasing internal reflections that would otherwise cause resonance. Several quality loudspeakers are built as a rectangular box so the question is...

How big a difference in SQ would the prism style speaker have over a standard box speaker?
First, I've never designed or built a speaker so I don't have much useful to add as far as your build.

How about more of a trapezoidal shape instead of triangular like my Ultra towers? Or is that pretty much what you're doing already?

SVS-Ultra-Tower_550.jpg
 
TLS Guy

TLS Guy

Audioholic Slumlord
First, I've never designed or built a speaker so I don't have much useful to add as far as your build.

How about more of a trapezoidal shape instead of triangular like my Ultra towers? Or is that pretty much what you're doing already?

View attachment 34176
I think that the usual reason for sloping front baffles is to correct the lobing error of odd order crossover, especially first. These crossovers give a 15 degree downward tilt to the listning axis. So sloping the front panel 15 degrees fixes this problem.
 
Guiria

Guiria

Senior Audioholic
Essentially yes, but steeper slope from top to bottom than those SVS speakers. I’ll try and copy or export my sketchup this weekend.

I’ve thought about making the bass cabinet rectangular and then my mid/tweet cabinet portion more trapezoidal. Perhaps that might be the way to go. Off the top of my head I don’t remember but is there a way to calculate the bracing distance needed to push the resonant frequency of an enclosure above the crossover frequency of the driver itself?

I’ll be crossing my 10” driver over too high to place it on the side, I did evaluate the style of build however because the narrower baffle is aesthetically favorable over a monkey coffin baffle imo.


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Pogre

Pogre

Audioholic Warlord
I think that the usual reason for sloping front baffles is to correct the lobing error of odd order crossover, especially first. These crossovers give a 15 degree downward tilt to the listning axis. So sloping the front panel 15 degrees fixes this problem.
Gotcha. Tho the front baffles of the Ultras aren't sloped (kinda hard to tell in those images), just the rear panel and sides. The front is straight up and down.
 
R

Russdawg1

Full Audioholic
I've been using Sketchup to draw some triangular style designs and I have to admit that thinking about building a triangular style speaker has me second-guessing going that route. I realize the primary benefit of a prism style design is that there would be no parallel edges thus decreasing internal reflections that would otherwise cause resonance. Several quality loudspeakers are built as a rectangular box so the question is...

How big a difference in SQ would the prism style speaker have over a standard box speaker?
If you are talking about reducing or eliminating standing waves inside the cabinet, then it doesn’t do much, audibly at least. For bookshelves.

When you get to big subs it becomes an audible problem.
 
Guiria

Guiria

Senior Audioholic
If you are talking about reducing or eliminating standing waves inside the cabinet, then it doesn’t do much, audibly at least. For bookshelves.

When you get to big subs it becomes an audible problem.
Yes that is exactly what I’m talking about. My speaker will be roughly 4 cubic feet with a 10” driver tuned to 27 hz. I have no problem bracing the speaker sufficiently, using batting or rock wool to stuff the speaker to help reduce standing waves and resonance, and using a double baffle to likewise help isolate the driver from the cabinet. I’m leaning more towards a box design lately.


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R

Russdawg1

Full Audioholic
Yes that is exactly what I’m talking about. My speaker will be roughly 4 cubic feet with a 10” driver tuned to 27 hz. I have no problem bracing the speaker sufficiently, using batting or rock wool to stuff the speaker to help reduce standing waves and resonance, and using a double baffle to likewise help isolate the driver from the cabinet. I’m leaning more towards a box design lately.


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As soon as you stuff it, all standing waves go away.

Double baffle is really only for heavy subs that need to the strength of the wood to hold it.

Bracing is good, the most effective thing you could add to the design.

4 cubic feet seems really big for a single 10” driver.
 
Guiria

Guiria

Senior Audioholic
As soon as you stuff it, all standing waves go away.

Double baffle is really only for heavy subs that need to the strength of the wood to hold it.

Bracing is good, the most effective thing you could add to the design.
If all standing waves went away then bracing wouldn’t be necessary as they are combating the same problem. At least that’s how I understand it.

4 cubic feet seems really big for a single 10” driver.
Yes it’s big. 3.9 cubic feet per bass box pro high fidelity suggestion. Actually a 28 hz tune, not 27;)




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Guiria

Guiria

Senior Audioholic
A very relevant article posted 17 years ago.



The author builds a trapezoidal speaker complete with sloped front baffle for time alignment.

Posting to keep the article tied to the thread.


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William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
If all standing waves went away then bracing wouldn’t be necessary as they are combating the same problem. At least that’s how I understand it.



Yes it’s big. 3.9 cubic feet per bass box pro high fidelity suggestion. Actually a 28 hz tune, not 27;)




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I think bracing is more for panel resonance and rigidity overall. The bracing shortens the panel length and also dampens it. And yeah, what is this 10” driver? Not many I know of that would like a 28hz tune unless it’s a subwoofer, and then that’s way too high.
 
TLS Guy

TLS Guy

Audioholic Slumlord
I think bracing is more for panel resonance and rigidity overall. The bracing shortens the panel length and also dampens it. And yeah, what is this 10” driver? Not many I know of that would like a 28hz tune unless it’s a subwoofer, and then that’s way too high.
There are 10" drivers that can dig deep that are not sub drivers.

I just posted about my little two channel system

So the main speakers use the KEF 139 bass driver. It has a cone area equivalent to a 10" driver. It is one of the best bass drivers of all time.

Here is the FR of those speakers.



As the B139 has long been unavailable new, but fetch high prices on eBay, people look for equivalents.

Here is a list of roughly equivalent drivers.
.
The Morel MW 1075 can have an F3 of 21 Hz.

I would also add the SEAS Exel 10" magnesium alloy cone drivers, I use in my dual TL lines.



When it comes to a TL actually often the best choices are not sub drivers. In those enclosures effciency is high and the pressure behind the driver over a lare range of support makes xmax pretty much a non issue.

I have no sub drivers in my reference system, but have all the power I want to 20 Hz and below, since roll off of TLs is 12 d per octave. So I can reproduce a 32 ft organ stop with power and authority and all the explosions Hollywood can throw at them.

This is the FR of that system in its new location at the optimal listening position in the second row of seating. There is no Eq of any kind and especially not Audyssey.
There actually is some room gain below 30 Hz.



So you see there is more ways than one of skinning the cat as they say.

At this time there is a massive and in many ways a misplaced obsession with subwoofers.

Actually using large drivers with massive motor systems and enormous amp power, is actually very poor, crude and inefficient design.

My moto is "right by design" and that is what I strive to achieve.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
There are 10" drivers that can dig deep that are not sub drivers.

I just posted about my little two channel system

So the main speakers use the KEF 139 bass driver. It has a cone area equivalent to a 10" driver. It is one of the best bass drivers of all time.

Here is the FR of those speakers.



As the B139 has long been unavailable new, but fetch high prices on eBay, people look for equivalents.

Here is a list of roughly equivalent drivers.
.
The Morel MW 1075 can have an F3 of 21 Hz.

I would also add the SEAS Exel 10" magnesium alloy cone drivers, I use in my dual TL lines.



When it comes to a TL actually often the best choices are not sub drivers. In those enclosures effciency is high and the pressure behind the driver over a lare range of support makes xmax pretty much a non issue.

I have no sub drivers in my reference system, but have all the power I want to 20 Hz and below, since roll off of TLs is 12 d per octave. So I can reproduce a 32 ft organ stop with power and authority and all the explosions Hollywood can throw at them.

This is the FR of that system in its new location at the optimal listening position in the second row of seating. There is no Eq of any kind and especially not Audyssey.
There actually is some room gain below 30 Hz.



So you see there is more ways than one of skinning the cat as they say.

At this time there is a massive and in many ways a misplaced obsession with subwoofers.

Actually using large drivers with massive motor systems and enormous amp power, is actually very poor, crude and inefficient design.

My moto is "right by design" and that is what I strive to achieve.
Wow! That FR of the reference system in its new home is excellent. As I’d expect!

My comment was perhaps made unfairly in haste. I do know there are some 10’s that are excellent, as you’ve illustrated. For some reason I made an assumption that the drivers in question were of a more pedestrian variety. I’m not so well versed in driver choices for speakers as much as subwoofers so that does leave me showing my backside a little.
Was I not correct in stating that bracing is more for panel resonance, cabinet damping and inertness than the standing wave issues that guiria was talking about?
And yes, I am also one of the subwoofer people. While I do run a house curve, my system is pretty well balanced and definitely not like that trunk rattling crap that rolls up and down my road. Lol
 
Guiria

Guiria

Senior Audioholic
Was I not correct in stating that bracing is more for panel resonance, cabinet damping and inertness than the standing wave issues that guiria was talking about?
Standing waves will contribute to panel resonance along with the energy from the driver itself in motion. A sturdy front baffle should minimize the transfer of energy to the rest of the enclosure. Stuffing, bracing, and fewer parallel sides should also help minimize the negative effects of resonance. I like to take a multi-modal approach.


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ryanosaur

ryanosaur

Audioholic Ninja
Watching this thread, I am reminded of:

and


Likewise, with discussion of time-alignment, there is this input from Troels Gravesen:



He also discusses in there the resonance and damping a little, considering his preferred medium is Baltic Birch and the Jansen speakers are all MDF. That said, I am reminded of the Second Best Speaker video and the discussion about using Marine Grade Plywood and laminating two panels together with DeciDamp 30. IIRC, he advised using 1/2" and 1/4" stock and laminating them with the DeciDamp. His testing was interesting enough that it stuck in my head. It's just after the 25 minute mark where dude starts discussing the resonance and damping of the cabinets.

As I'm approaching my first builds within the coming months, this has been an interesting topic. I do feel, however, that there is a point in the chasing of the perfect cabinet where diminishing returns is achieved. I think it was Poes, IIRC, that shared a story about a Sub he built that was stupid heavy with the use of Window pane braces and MDF... to the extent that he and a friend couldn't move it out of his basement. :eek:
His recommendation to me was to use Baltic Birch and Dowels for the bracing with the advice that well placed bracing like that was more than sufficient to do the job and keep the cabinet inert enough to not introduce its own resonant distortions.
 
KEW

KEW

Audioholic Overlord
Four of the 2200s at one time would be USD 1359 shipping included.
No, the 2200's have been going for "3 for $800" since the beginning of the year. That is $233/each. I bet if you called them, they would sell you a fourth at he same price if you ordered all together, making it $1033 for 4ea.
Link:
 
lovinthehd

lovinthehd

Audioholic Slumlord
No, the 2200's have been going for "3 for $800" since the beginning of the year. That is $233/each. I bet if you called them, they would sell you a fourth at he same price if you ordered all together, making it $1033 for 4ea.
Link:
Yeah I know that now, and not sure then I knew how to view their multiple unit pricing, but my post was from November, too. Not in the market, as I have extra amps now, but if I were, that three-fer pricing is pretty good. Altho I'd probably still just buy two Crown XLS1502s instead....
 
Guiria

Guiria

Senior Audioholic
Those outlaws seem like they would be too much power for my mid/tweet amps. I like the output for my bass drivers though.

I’ve thought of buying a 5 channel amp such as from Emotiva and just not using a channel. That’ll be a fun time when it’s time to buy the power.


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