Golden Trapagon: Ideal vs Reality?

[Robert R]

I'm about to embark on the design of HT in a house we're remodeling. I've got plenty of room for a decent size and design (at least 10x6x23, room within a room, etc.). Searching the net, there's lots of sites that assert that the Golden Trapagon is the preferred shape. Few of these sites are actually HT builders.

However, when I look at the sites of actual HT designers and builders and their portfolios, I rarely see a GT actually built (as best I can tell) for a dedicated HT. Rather, it seems that regular cubiods are used (perhaps Golden Cubiods after Sepmeyer) and room modes are treated using conventional methods.

Thus, the GT seems to be perhaps an ideal, but when it comes to actually building an HT, the perfect is the enemy of the good--or at least real-world budgets and contractors.

Also, I'm starting to interview HT designers in the Bay Area, so if you ra recommendation, feel free to pass it along.

Thanks,

 

[Blumlein 88]

I think the missing part of these things is where you put speakers and listeners also effects the heard peaks and nulls. You can have a perfect ratio and still have bad places for speakers/listeners. Even irregular spaces (like car interiors) have modes. Non-parallel surfaces don't eliminate or reduce modal frequencies as much as is imagined. I think all things considered well chosen rectangular dimensions and treatment are not going to be enough inferior to a difficult shape like a trapagon to be a big impact on sound.

If you want to play around with dimensions and such here are a couple of good simulator sites.

https://amcoustics.com/tools/amroc?l=26.16&w=17&h=12&ft=true&r60=0.6

https://www.acoustic.ua/forms/rr.en.html

I can say, I once knew someone with a room that was rigid metal walls with the same 11 ft (3.3 m) in all dimensions. It was on the small side, but it was the most horrible sounding room ever by far that I've heard.

 

[Robert R]

Thanks. I have a bunch of room mode calculators I've sourced and developed in spreadsheets, but I have to say the first link above is one I've never seen before, and very cool.
As to speaker locations, I'm going theater style so in the plane of the screen, and viewing distance based on screen size, so probably around 13 feet in the main row.

 

[andreasmaaan]

I wouldn’t bother with a GT if I were designing a room. The benefits are not significant with respect to the considerable costs/difficulties involved in design and construction.

Instead, after ensuring the ratios of room dimensions were adequate rather than “perfect” (the room calculators you mention will do the job here), I’d put my money and efforts into room treatment and digital room correction.

A well-proportioned right-angled room with good treatment, well-placed subs and room correction will give very smooth bass over a broad range of seating positions.

 

[Robert R]

Thanks, that was my assumption.