How to choose speakers and setup for stereo

[Jfs]

I am looking to set a listening area for a stereo system:
I have read the articles on the website: Room Acoustics, System Layout & Setup
I have also been looking at this website: http://realtraps.com/art_room-setup.htm

The layout at realtraps looks good, but I still would like some feedback on setting up my room. I'm not understanding the articles enough to feel comfortable to implement. I live in a basement; I have uploaded a sketch I made of the room measurements. I was thinking of having the speakers at the front of the room, where I have the 14' measurement drawn. Putting things the other end probably won't be practical.

I'm not sure what I should get for speakers; am hoping that figuring out the best listening position will help with understanding what I should choose for speakers, and what I will need for amplifier power. I was thinking of using some larger bookshelf speakers since I have read that they will be better for midrange with a smaller cone than they of floor standers (appreciate advice on speaker selection), and I am also hoping to contain the sound from my neighbour upstairs, at least as much as possible.

According to the 38% rule that will leave me about 7' from the wall for a listening area. If I put the speakers 2' from the wall that will leave me 5' from the speakers. I'm thinking that this will help to keep the volume down as I am closer. Would like to know if this is a good distance for listening and soundstage?

I need to keep costs down so would appreciate references to material for a novice to help apply this and maybe a test tone CD or other method to help place speakers and any materials to help condition the room. How hard will this be for a novice to do and what can I expect on a budget. Can I build materials myself? I know I won't get 100%, but hopefully enough so it will sound good and keep my neighbour happy.

 

[TheWarrior]

http://philharmonicaudio.com/aa.html

I think you need to just order those speakers because there really isn't anything else out there that offers what these do for the price, especially with bass.

The 14' wall seems the best choice for acoustics, it is better to have a long room than a wide room. I wouldn't get caught up in this 38% rule, just trust your ears. When setting up speakers you need to adjust the distance to the wall behind (can affect bass, and midrange cancellations) first, and the amount of toe in so that they sound the same at all seats which may require you to then adjust the distance between the speakers. Again, the goal is equal sound at all seats!

Back to my comment on long room vs wide, and part of where this 38% theory comes from, is that you don't want to be too close to the rear wall, the reflections off the rear wall will arrive at your ears near the same time as the direct sound, confusing the sound stage.

Room treatment is the LAST step. Realize that normally furnished rooms often contain the elements they need like fluffy padded (absorptive) couches and pillows, decorative art and book shelves that scatter sound, etc.

Otherwise, I would listen to familiar music on repeat and learn to listen critically. Trust your ears and have fun!

 

[Jfs]

Those speakers are 84.5 db and 6 ohms. How does that relate to an 8 ohm speaker? What do I need for an amplifier to power these speakers for volume and resistance? The speakers being 6 ohms will probably need an amp that can put out more current. How far away would you put these speakers from the listening positiion? I sent an email to the company and see what they say.

Thanks,

Joe

 

[TheWarrior]

Those speakers are 84.5 db and 6 ohms. How does that relate to an 8 ohm speaker? What do I need for an amplifier to power these speakers for volume and resistance? The speakers being 6 ohms will probably need an amp that can put out more current. How far away would you put these speakers from the listening positiion? I sent an email to the company and see what they say.

Thanks,

Joe

Any receiver would be able to power them, the lower sensitivity just means you need to turn the receiver up an extra notch or two to reach the same SPL with speakers of higher sensitivity.

Impedance is not so much an issue until a speaker dips below 4 ohms, it can place too high of a demand on a limited power supply like those found in receivers.

Audioholics just did an article on this subject, take a look! http://www.audioholics.com/loudspeaker-design/speaker-impedance

Dennis Murphy is active on this forum, and is whom you would be communicating with at Philharmonic. Like a number of people here, I too am a proud owner of his speakers!

 

[Jfs]

Thanks, I enjoyed the article and links in it. I am a little confused about something:
In one of the links:
http://www.audioholics.com/loudspeaker-design/loudspeaker-sensitivity
"if a speaker has a lower impedance, it will play louder for the same voltage input from the amp"
How does this relate to the amount of power from the amp and the speaker volume? Won't the total volume of each amp end up the same?

 

[TheWarrior]

Impedance is a property of AC circuits. It is like resistance but it also possesses phase and magnitude. (there is no difference between resistance and impedance in a DC circuit)
It's magnitude represents the difference as a ratio between voltage and current.

In simple terms the higher the Impedance of a speaker, the easier it will be for an amp to drive it. However, the higher the impedance, the lower the sound output will be (higher ratio = lower voltage/current).

This also expands to include multi driver loudspeakers as the impedance behaves differently depending on the circuit:

Parallel = half impedance
Series = double impedance
Series-parallel = no change

This knowledge allows a loudspeaker designer to combine drivers of varying impedance.

Example: 1x 4ohm Tweeter, 2x 8 ohm Woofer in a 2 - way loudspeaker.

Wiring the woofers in parallel halves the impedance, allowing the load they present to the circuit to match the tweeter.