Home » Sponsored » Pi Speakers » Why 7pi? 7pi and listening room considerations
Why 7pi? 7pi and listening room considerations [message #53231] Thu, 19 February 2009 01:22 Go to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount

Background- wanted to try horns and so constructed DIY speakers using Selenium 220Ti on JBL PT-F95HF waveguide paired with Pioneer HPM-100 woofers. Quite satisfactory, though not life-changing sound. However, discovered CD and now prefer it to much-loved Yamaha NS-1000M. Wishing to pursue the interest in DIY CD designs brought me to PiSpeakers- the Pi7 appears from an amateur perspective to be 'all CD' (in comparison to (e.g.) Pi4). This is the logic for choosing the Pi7 as the 'next step' on a CD journey. Comments?
Constructed a dedicated listening room 6m (20’) X 3.8m (12.36’) X 2.3m (7.64’). Any considerations with Pi7 and these dimensions? Is 12 ft too narrow to take advantage of the Pi7 CD design on the horizontal plane? One end of the room has built-in bass-traps and mid-high absorptions panels from Ethan Winer's design www.ethanwiner.com/acoustics.html.
As you can see in the photo, four bass traps (plain wood colour) meet in the corners (LH side wall partially obscured by curtain, RH back wall under C.D.s), with two absorbers (cotton covered) in the centre of the wall. Any issues with the Pi7 back-firing woofer and the bass traps of this design?
Thanks.


7pi and listening room considerations [message #53232 is a reply to message #53231] Thu, 19 February 2009 12:23 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)
Panel absorbers are usually pretty effective for room damping. Should be great with seven π cornerhorns and your room layout looks good for them too.

The four π loudspeaker sounds wonderful, and doesn't lose much to the seven π when properly setup. However, if you have a suitable room, the seven π cornerhorns do sound better. They generate sound with uniform spectral balance throughout the entire room and it isn't just the top end of the spectrum, it's nearly the whole audio spectrum. The blend between midhorn and bass bin smoothes floor bounce and the higher modal frequencies too. In your room, I would expect the seven π cornerhorn to sound very nice.


http://www.pispeakers.com/photos/7Pi.jpg
seven π cornerhorn

Re: Why 7pi? 7pi and listening room considerations [message #53233 is a reply to message #53231] Fri, 20 February 2009 16:23 Go to previous messageGo to next message
PaulW is currently offline  PaulW
Messages: 71
Registered: May 2009
Location: UK
Viscount
Hi, I use the 7's in a slightly smaller room than yours (width/length) but a bit higher and they do sound great. Just posted a review in the shopping area.

Regards

Paul

Thanks! [message #53234 is a reply to message #53233] Fri, 20 February 2009 17:38 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

Thanks for the review, Paul!


Re: Why 7pi? 7pi and listening room considerations [message #53239 is a reply to message #53233] Sun, 22 February 2009 18:12 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
Paul, I've read your build thread NUMEROUS times. To someone considering the project, that kind of information can be a 'deal breaker'. Took notice of your room dimensions, too. Although there are quite a few who feel the JBL woofer is a better sounding unit, its a wee bit pricey- looks like I'll be opting for the Eminence job.
Did you ever re-build the mid-horn housing? It looked fine from the photos.
And cheers for the review- you sound a satisfied gent!

Re: Why 7pi? 7pi and listening room considerations [message #53240 is a reply to message #53239] Sun, 22 February 2009 19:35 Go to previous messageGo to next message
PaulW is currently offline  PaulW
Messages: 71
Registered: May 2009
Location: UK
Viscount
I've no doubt the JBL unit is better, but I had to draw a line on the budget somewhere and it was more important for me to get the best treble, so the B&C DE250 was a must have. Now if I was going for the 4 Pi, then I suspect the JBL would really come into it's own as it is doing more work. All the problems I now have in the bass region I suspect will be sorted out with better output transformers in my Bottlehead amps which will provide better and tighter bass control.

I've not started the re-build of the mid-horn yet (a project for this summer as I'm still using my outdoor workshop) but the main reason is to put together a slightly larger flair, but also have it completely exposed, with just the drive unit enclosed in a box (any thoughts Wayne?).

Yes, satisfied enough to want to listen more than tweak or build or change or.....

Paul

Re: Thanks! [message #53241 is a reply to message #53234] Sun, 22 February 2009 19:54 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
Wayne, in response to jimbot enquiring the application of Delta 15, you wrote:

Use the same midhorn, tweeter and crossover as the seven π cornerhorn but scale the bass bin larger, like the version for the JBL 2241, but tune it for 22Hz using a 4" long, 4" diameter port

Some more questions to further clarify, if I may;
In your testing and listening experience, would you consider the Delta Pro 15A model to be a performance compromise over the Omega Pro 15? (Purely budgetary motivated question, I can interpret the specs well enough).
Regarding the larger cabs you suggested for the Delta 15- Presently I have 37" high bass bins- and they're TALL. Higher cabinets than this would put the mid/high drivers above seated ear level. With respect to the null axis, is this a problem? I presume the Omega Pro would also produce lower response in the bigger cabinet without changing the crossover- true?

Re: Thanks! [message #53242 is a reply to message #53241] Sun, 22 February 2009 19:57 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
EDIT- should read (... I CAN'T interpret the specs well enough)! Bad typo.

Re: Why 7pi? 7pi and listening room considerations [message #53243 is a reply to message #53240] Sun, 22 February 2009 20:13 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
Paul, thanks for the feedback. I can relate to the budget considerations- gets out of control easily, doesn't it?
What is the motivation for leaving the horn flare exposed? Do you suspect resonances within the enclosed version? Just a thought- perhaps (e.g.) filling the horn chamber with plaster would address this.

Re: Why 7pi? 7pi and listening room considerations [message #53244 is a reply to message #53243] Sun, 22 February 2009 20:42 Go to previous messageGo to previous message
PaulW is currently offline  PaulW
Messages: 71
Registered: May 2009
Location: UK
Viscount
No just fancy the more skeletal look really and using the same overall Birch ply finish as the bass unit.

Paul

Previous Topic: Can you guess horn cut-off by dimension only?
Next Topic: Delta 15 in 7 Pi?
Goto Forum:
  


Current Time: Tue Nov 05 17:28:39 CST 2024

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Miller Audio
Miller Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest