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New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69318] Sat, 03 September 2011 21:22 Go to next message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
Hi,

I am quite a newbie in DIY so please bear with me..

I am looking to build a HT room in the house i just bought and before the complete the renovation, i need to sort of figure out what sort of speaker systems to have (sizes, etc).

I have heard that the 4pis are great.. so, this is why I have joined this forum.

Ok, here are some questions.. I hope I can get some answers.

First, placements for my speakers:

- I intend to hide the speakers inside a purpose built cabinet (my room will be built by carpenters). I hope this would not distort the sounds.

1. What's the difference between the 4pis, and 7pis corner horn? as LR speakers? Do you have to place the 7pis in a corner or just anywhere?

2. 4pis only goes up to 16khz, would this affect the normal playing of music? Or, would the JTR 12s be better option?

3. What sort of sub should i build to complement these speakers? Should I build the 12pi base horn, or say build one using the TC Sounds LMS Ultra 5400 18" DVC Subwoofer? Basically i don't know much about subwoofers and what i would need to complement these speakers..

4. Could I use a regular Receiver to power the 4pis (say if i use them as LCR, and the 2pis as surround?) or, do i need separete amps for them? If i use separate amps, how do i hook it up? do i still hook the source material to my receiver, and then output to the amps, and then output to the speakers? Wouldn't that be double amplification?

That's all i can think of for now..
Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69321 is a reply to message #69318] Sat, 03 September 2011 22:18 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18675
Registered: January 2001
Illuminati (33rd Degree)

Answers by numbers:

1. The seven π cornerhorn is a constant directivity cornerhorn. The four π speaker is a matched-directivity two-way loudspeaker. The difference is that a constant directivity cornerhorn provides constant directivity from the Schroeder frequency up, all the way through the audio band. A matched-directivity two-way speaker is the next best thing, having a pattern that collapses gradually up to the crossover point, where it becomes constant. More information is available in the following article:
If you have the right corners, I'd suggest the seven π cornerhorn. Nothing images like those, but again, it requires the right room. That means corners that are unobstructed for at least five or six feet, and it's usually best for them to be placed along a short wall. You need to be able to sit back behind where their forward axes cross, which is 1/2 the distance that the wall is long. In other words, if you are placing the speakers at each end of a 20 foot wall, you have to be able to sit more than 10 feet back from that wall. That's an ideal placement.

If you don't have the right corners, the matched-directivity two-way speaker is the next best thing. Run them with flanking subs for the best results. A matched-directivity two-way with flanking subs is 95% as good as a constant directivity cornerhorn, and has the benefit of greater placement flexibility. But to get this kind of performance, you'll need to set them up as shown in the document referenced above, similarly to the cornerhorns, with 45° tow-in, forward axes crossed in front of the listeners and flanking subs a couple feet away from each main speaker in each axis. I like having the mains on stands, and flanking subs on the floor beside them and behind them. Like this:

http://lonestaraudiofest.com/2011/Photos/LSAF_2011_115.jpg


2. All models with the (upgrade) DE250 compression driver reach 18kHz. They're smooth and extended, and offer the dynamics and low distortion that only a compression driver can provide. Other tweeters can hit 20kHz, and sometimes even more. But none can do it with the dynamics of a compression driver. I'd trade the dynamics for that last 2kHz any day.

3. I'd suggest the three π subwoofer for home hifi and home theater. They provide plenty of good, clean, powerful bass and their relatively small size allow you to use several of them in a multisub configuration. Use at least two as flanking subs, and possibly two more at the other side of the room, if space permits. More information on that in the following link:
4. A "regular" receiver is all that's needed to drive any model of π Speakers. Of course, you'll want it to be a good quality unit. No sense getting the best speakers and driving them with a mediocre amp or source.

Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69322 is a reply to message #69321] Sat, 03 September 2011 22:48 Go to previous messageGo to next message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
Thanks for the detailed reply.

Now to the business end.

Could you ship the kits to Malaysia? Time is not a problem for me because i still need to renovate my house and that takes time, so I would build the speakers first, before finalizing the design my of ht to match the sizes of the speakers..

What do you recommend for the surrounds? Would the 2pis be enough?

Also, I know this is a competitor, but would a JTR 12 be better as a center channel? or another 4pi? Have you heard the JTRs? would they complement the 4pis?

Ok, this may be a silly question... we use 240V here in Malaysia vs the 110v in the US.. does this have anything to do with the drivers in the 4pis?

Sub question: Could I upgrade the 3pi sub with LMS Ultra 5400 18? using your kits? i mean, basically build a bigger box, but use your crossovers, etc.. i want to get HUGE base with powerful punches... I heard that that is the best sub driver around from the avsforum.. (or, am i naive to think that?)

Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69323 is a reply to message #69322] Sat, 03 September 2011 23:21 Go to previous messageGo to next message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
I haven't made up my mind about which receiver to use yet..

how about this one?

Onkyo TX-NR709 7.2

Would it be good enough?

It has 2 hdmi out, which is great for both my LCD tv and projector...

How do i power 4 subs from such a receiver? I mean, if i got the 4pis as the main speakers, and the 3pi subs to complement each, how do i hook it up? does the sub have an 'output' to the main speakers?

Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69325 is a reply to message #69323] Sat, 03 September 2011 23:47 Go to previous messageGo to next message
NWCgrad is currently offline  NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...
Master
I will have a pair of 4 Pi's (upgraded to the JBL woofer and DE250 CD) and 2 modified 3 Pi subs in Phnom Penh by the end of the month.

If you find yourself in the area you could stop by for a listen.


VIRIBUS MARI VICTORIA
Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69326 is a reply to message #69325] Sat, 03 September 2011 23:54 Go to previous messageGo to next message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
NWCgrad wrote on Sat, 03 September 2011 23:47
I will have a pair of 4 Pi's (upgraded to the JBL woofer and DE250 CD) and 2 modified 3 Pi subs in Phnom Penh by the end of the month.

If you find yourself in the area you could stop by for a listen.


Great, i'll definitely take you up on that.. it's just an AirAsia flight away and I have been to Phnom Penh. Please update this thread when you have it all built!

How did you modify the subs?
Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69327 is a reply to message #69326] Sun, 04 September 2011 00:40 Go to previous messageGo to next message
NWCgrad is currently offline  NWCgrad
Messages: 143
Registered: March 2010
Location: Frederick, United States ...
Master
I am building as sealed instead of vented so I can get away with a smaller box due to space constraints. I am giving up deep bass (from low of 20 Hz to ~45 Hz) with the smaller boxes. I will power them with an old two channel amp I brought over from the states (Adcom GFA555) that is rated for 200 watts into 8 ohms.

VIRIBUS MARI VICTORIA
Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69328 is a reply to message #69327] Sun, 04 September 2011 00:45 Go to previous messageGo to next message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
NWCgrad wrote on Sun, 04 September 2011 00:40
I am building as sealed instead of vented so I can get away with a smaller box due to space constraints. I am giving up deep bass (from low of 20 Hz to ~45 Hz) with the smaller boxes. I will power them with an old two channel amp I brought over from the states (Adcom GFA555) that is rated for 200 watts into 8 ohms.



Cool, I guess you don't need the bass as you have the 3pi bass units... i'll def take u up on it once you have finished them. Good luck with your build...
Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69333 is a reply to message #69322] Sun, 04 September 2011 01:23 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18675
Registered: January 2001
Illuminati (33rd Degree)

coolgeek wrote on Sat, 03 September 2011 22:48
Could you ship the kits to Malaysia?

Yes, we ship around the world. Use the shopping cart to check shipping prices. Start an order and let it calculate shipping prices for you. It won't ask for payment information until after the shipping quote, so you can back out or complete the order if you wish.

coolgeek wrote on Sat, 03 September 2011 22:48
What do you recommend for the surrounds? Would the 2pis be enough?

Yes, perfect.

coolgeek wrote on Sat, 03 September 2011 22:48
Also, I know this is a competitor, but would a JTR 12 be better as a center channel? or another 4pi? Have you heard the JTRs? would they complement the 4pis?

I like Jeff a lot, he's a great guy. But I wouldn't want a different speaker for a center channnel. It is a coaxial speaker, having different polar response, and probably different spectral balance and character. You don't want that. The center channel speaker should be the same as the right and left speakers.

My advice is to forego the center channel entirely, unless the distance between right and left channels is greater than about 20 feet. The crossed-axes configuration makes a wonderful phantom center with great imaging and detail.

coolgeek wrote on Sat, 03 September 2011 22:48
Ok, this may be a silly question... we use 240V here in Malaysia vs the 110v in the US.. does this have anything to do with the drivers in the 4pis?

No.

coolgeek wrote on Sat, 03 September 2011 22:48
Sub question: Could I upgrade the 3pi sub with LMS Ultra 5400 18? using your kits?

No, but subwoofer design is very easy, at least direct radiating subs. The mains have issues to deal with but not the subs. You can pretty much simulate the box with a T/S program and expect the device to act the same as the simulations.

One word of advice though - don't build one massive sub. Build two to four competent subs that are easy to put in different places around the room. Multiple subs are much better than one powerful sub.

Put two subs flanking the mains, as I showed earlier. If you build two more, put them on the opposite side of the room somewhere. That will make the bass smooth and full throughout the room.

Re: New HT - Need Advice on Speakers - 4pis or 7pis for main, 2pis, and what to use for bass [message #69334 is a reply to message #69333] Sun, 04 September 2011 01:45 Go to previous messageGo to previous message
coolgeek is currently offline  coolgeek
Messages: 8
Registered: September 2011
Esquire
Wayne Parham wrote on Sun, 04 September 2011 01:23

No, but subwoofer design is very easy, at least direct radiating subs. The mains have issues to deal with but not the subs. You can pretty much simulate the box with a T/S program and expect the device to act the same as the simulations.


What's a ts program? can you send me the link to buy it?

Quote:
One word of advice though - don't build one massive sub. Build two to four competent subs that are easy to put in different places around the room. Multiple subs are much better than one powerful sub.

Put two subs flanking the mains, as I showed earlier. If you build two more, put them on the opposite side of the room somewhere. That will make the bass smooth and full throughout the room.




This brings me a couple more questions regarding the subs.. I was looking at your 3pi sub kit... does it include the 400watt amp? If it does, can you send one which is 240v? and if not, how do i add an amp to it? can you suggest amps for this? Also, how do i hook up a 4pi with a 3pi sub together? Should the out from my receiver go into the 4pi which then has an out to the subs? If I am not mistaken, the receivers have ONE out for each main channel only. This is the confusing part.. i know how to hook up powered subs.. ie, thru the receivers' sub-output.. but not passive subs, especially as per your recommendation of hooking it up with the 4pis..

---

I was adding stuff to my cart then relize that upgrading the capacitor - Audience AuriCaps costs over $200, which is very significant. Should i add this, in your opinion or just the cheaper upgrade of $50? Does it make a lot of difference?

---

Final question on the 4pi build, i notice that apart from the square port, the other parts of the speakers looks great.. the sauare hole is just ugly.. could i replace that square hole with a commercial flare port?:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-350

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