This New Area Must Be An Omen!!!

[Lasher]

The other day I ordered a Parts Express Catalog and It arrived Yesturday. On the cover are these to huge line array speakers that just look..........well............WOW!

Needless to say it got me thinking DIY. First off let me say that I have never built a speaker before but I do have a reasonable understanding of how they work. I also am a custom cabinet maker by trade so woodworking is something I am very good at. I don't have my own shop but I believe I could use the shop I work for on the weekends.

Long story short I want to build those speakers on the cover for my own Home.
What I need is information on the internal workings of such huge speakers.

How are they crossed over? They seem to have 11 drivers. One of them is a large planer down one side, then beside it are 8 midrange or maybe midwoofers, and at the bottom are 2x12"-15" woofers or sub-woofers I can't tell from the cover shot. These speakers are around 7' tall.

How are they filled? Are they packed with acustic foam and what kind of bracing should be used inside of the boxes.

Are they ported or sealed? Are the 2 woofers/subwoofers actual drivers or is one a passive radiator?

In other words anyone who has built speakers like this who can send me step by step instructions on how to build these would be a god send.
If not then any help from the AVS DIY'ers should help almost as much. :)

Thanks in advance.

Lasher

Here is a link to the catalog with a pic of the cover: http://apps.pesupport.com/catalog/catalog.cfm

[derekbannatyne]

If you shoot an email to Parts Express they would probably be able to give you details on the speakers. I built some cheap 2-way speakers myself, but used premade crossovers and no filling so I can't really help you there.

[thylantyr]

What is your project budget ? Maybe a better design can be achieved than
the one on the PE catalog. If you are curious, send me a PM and I'll send you
pics of line arrays that others have built for inspiration and maybe throw some
esoteric ideas your way to digest. ;)

[polar]

http://www.partsexpress.com/projectshowcase/colossi/index.html

If you haven't seen them yet, the speakers are on the project page.

Sorry to bump such an old thread, but I was looking for info about these specific monsters myself.

[thylantyr]

Sorry to bump such an old thread, but I was looking for info about these specific monsters myself.

A better design can be done for less money :) I see the potential to save ~$970
with a more optimized design of the line array. With the money saved, you can
take the array to a higher level of sound by going to a digital crossover for $250
and buy an extra amplifier to actively bi-amp.

Add a seperate subwoofer not integrated into the line array tower
for more flexibility and to be more future proof.

[Jeremy Snow]

[QUOTE=thylantyr]Sorry to bump such an old thread, but I was looking for info about these specific monsters myself.

A better design can be done for less money :) I see the potential to save ~$970
with a more optimized design of the line array. With the money saved, you can
take the array to a higher level of sound by going to a digital crossover for $250
and buy an extra amplifier to actively bi-amp.

Add a seperate subwoofer not integrated into the line array tower
for more flexibility and to be more future proof.[/QUOTE]

What "more optimized" are you talking about? I have been contemplating this build as well but like you have thought about doing digital crossovers. I was thinking of putting the amps in the speaker base and running balanced signal cables to the speakers.

[Jack Gilvey]

Apparently, the primary design goal was to make a big speaker for the cover of the catalog.

http://www.htguide.com/forum/showthread.php4?t=18824

I like the active bi- or triamping idea, though, as it should make things easier for crossover novices...I think.

[Scott Simonian]

Jack - First I though of when I read the first sentence from the OP was the thread over at HTGuide.

[thylantyr]

Apparently, the primary design goal was to make a big speaker for the cover of the catalog.

snip....

much of the overall guidance came from the Parts Express’ Advertising Department and Graphic Designers. They wanted a speaker that was unique, modern, and most importantly, physically impressive.

http://www.partsexpress.com/projectshowcase/colossi/index.html

I don't blame their approach to marketing, other companies do it as well.

[thylantyr]

[QUOTE=Jeremy Snow]What "more optimized" are you talking about? I have been contemplating this build as well but like you have thought about doing digital crossovers. I was thinking of putting the amps in the speaker base and running balanced signal cables to the speakers.[/QUOTE]

The BG planars are over-rated and over-priced. Their 88dB sensitivity rating
is rock bottom. You can make a line of PT2 planars for $200 - $250 per
tower, either a eight or ten line and have the option to configure your
sensitivity much higher. My budget 'Rob Array' is a ten line of PT2 with
104dB caculated sensitivity, but it's an 0.8 Ohm load for the amplifier.
As long as you have a decent amp, it can drive that low impedance. I ran
a ancient Adcom 555II with no issues until I ran the amp clipping playing
heavy metal music, it would heat up eventually and go into thermal protection,
for a normal listening session, it's a non issue. I run four bridged QSC PLX3402's
on that array. Imaging running 0.8 Ohm per bridged amp, everyone will say
no, I say yes and it's been running well with no issues. The sound is more amazing as I doubled my clipping headroom.

http://home.pacbell.net/lordpk/robarray/

The Collossi uses a good midwoofer, the same one I recommend for this
'East-West' line array design I help conceive in Aug. 2005.
http://www.caraudioforum.com/vbb3/showthread.php?t=224281&highlight=east-west

I recommended a ported design to extract more bass performance and
to mate to a seperate subwoofer as an option, not as a mandatory
thing. I'm 98% sure if you only listened to music,
you'd probably be happy with the ported array as is, an array of small ported
drivers can do amazing things. My budget array uses 49 cent midwoofers,
4 inchers rated for 5w rms, yet I'm able to extract over 126dB of upper midbass
SPL and knock stuff off the television. The Dayton RS midwoofers are superior
and would do more amazing feats.

The Behringer DCX2496 is an amazing crossover for $250 shipped. Get
two high powered pro audio amps and your array will be sweet.

If you are serious, start your own thread and we can throw more details your
way and help concept your design. If you choose passive crossover design
and a higher speaker impedance and lower powered amps, you'll be missing
the big boat on what the line array can do.

[bobgpsr]

[QUOTE=thylantyr]...My budget 'Rob Array' is a ten line of PT2 with
104dB caculated sensitivity, but it's an 0.8 Ohm load for the amplifier.
As long as you have a decent amp, it can drive that low impedance...[/QUOTE]

So you would need either 8 or 16 speakers to get a more normal
overall impedance when wired series/parallel but with equal current
flow in each speaker?

Bob

[thylantyr]

[QUOTE=bobgpsr]So you would need either 8 or 16 speakers to get a more normal
overall impedance when wired series/parallel but with equal current
flow in each speaker?

Bob[/QUOTE]

The magnetic planar tweeter has weak vertical dispersion, the only realistic way
to get a sensitivity boost is to wire the array for low impedance. ie,
if the individual planar is 8 ohms, rated for 94dB, you only realize 94dB
if you wire the whole array for 8 ohms no matter how many you stack up.

But for other drivers like domes/cones, you get the added benefit of mutual
coupling which aids in sensitivity boost. That's why I wired the planars for
0.8 Ohm as it was the only method to boost array sensitivity. I also have a switch
to select 3.2 ohms or 0.8 ohms wiring, 98dB sensitivity or 104dB [lowest impedance].

The midwoofers also have a switch to select 2 or 8 ohms, 2 ohms giving
the highest sensitivity.

If you were to use the proper dome tweeters instead of planars as the
tweeters, you can get mutual coupling benefits.

The goods news that eludes people, the modern good amplifier is able
to drive low impedance tweeters much easier than meets the eye so you
can design an abnormal system and have it perform well.

[Jeremy Snow]

Being new to all of this, yet eager to learn as much as possible I have a few questions.

[list=1]
My goal is accuracy of reproduction. Why would I want higher SPL if my goal is accuracy and as flat of a response as possible? I understand sensitivity and the resulting power requirements, yet ultimately efficiency is not a concern. I have a Marshall half stack that can shake things off the TV with less than 75 watts but that is not the goal is it? Or I am I missing something here? The high sensitivity speakers in the Marshall cabinet have very very high sensitivity yet induce their own unique color to the way am electric guitar sounds. I assume that this would not be true by wiring the PT2's to decrease their overall impedance.
With the use of the PT2's wouldn't there still be some sort of combing as you have stated that these speakers have little vertical dispersion? This is why the B&G caught my attention initially.
[/list]

I have read through some of your linked posts on other sites and have concluded that if you will allow, I will be asking you a lot of questions in the coming months.

[thylantyr]

Being new to all of this, yet eager to learn as much as possible I have a few questions.

If you are new to this stuff, the first thing you need to figure out is audio is not a
black or white scenario that people claim it is. People want 'this or that' but what
they hear may be something else.

Most people that do amplifier uprades welcome the additional power/headroom
and associate the experience with better sound using clever descriptive words to
describe their new experience. This is essentially more clean SPL they are experiencing but will not admit they love the high power.

Eventually your speakers will reach limits and no matter how much more
amplifier power you drive them with, you will need a new speaker to boost
the experience to a newer level.

Use the drummer playing drums as the example. When your friend plays
drums with no amplification, if he is skilled, the sound is very clean, no distortion,
very dynamic, high impact, etc. This is really a high SPL experience, but most
people may not realize it because the sound is so clean and unstrained.

If you want to translate this experience into a home speaker system you need
a high SPL clean sounding design.

If the Marshall half stack doesn't sound good, then blame the 'audio system'
{speakers w/amps, etc}, don't blame the idea that the bad sound is caused
by the idea of high sensitivity or high power.

When you stack planars, it's not a continous line as there is a gap between
drivers. To hear this effect you place your ear inches away from the gap
and you don't hear much sound as if your ear is aimed right at the driver itself.

If you listen to your music at a greater distance {greater than inches}, then
you won't peceive this effect. In my case, I can listen to the array at 2 feet
and not hear any gremlins.

You can design a system with more comb filtering {not ideal}, but if your
listening distance is increased, you will hear less of it's effect, but that is
not the goal when you design one. For instance, the $20k McIntosh home
line array has a very bad design on dome tweeter spacing, ideally you should
place the tweeters at 1/2 inch or less apart stacked, they used 2.75" inches.
Given their 20+ years of line array experience where they stacked tweeters
very close {20 years ago), later they opt for a design that is worse. I don't
know any line array DIY'er that would even attempt such a poor design,
yet they sell the product today. /hehehehe

If you don't care about SPL, why not just get some great headphones?
If they aren't loud enough, then you do like higher SPL ? :)

If you like a live performance, the line array designed for high sensitivity
mated to monster amplifiers is the best kept secret in audio. /shhh/

Make a prototype and check it out. I never build a speaker unless I have
done a one cabinet proto to verify if it's going to do what I want. Use cheap
wood and 'ok' construction methods just to get an idea.

[Jeremy Snow]

The coloring that the Marshall does is not a bad thing at all. It is what produces the unique sound of a Marshall which is quite different from a Fender Cab. My point was that I am used to such high SPL drivers for instruments becoming part of the instrument. One would never use a Marshall cabinet connected to a SACD player to try and reproduce the original. My question was and I think you have answered it, do higher sensitivities fundamentally effect driver response? No.

I once sat right next to the Bass Cellos in an orchestra, 3 feet away, that experience was amazing, I want to reproduce that experience! Your connection on SPL to live performance is the most important thing you have written. I want to simulate a live performance with as much as accuracy as DIY possible. Therefore, SPL becomes a major player in my design considerations.


Next question...

What is the effect of multiple line arrays, say a wall of PT2's or RD50's, ignoring stereo for the moment?

[thylantyr]

DIY line array popularity increased due to this;
http://www.audiodiycentral.com/resource/pdf/nflawp.pdf


The RD ribbons aren't interesting for me because of the low sensitivity as I rate sensitivity
high because it's a personal preference. Others aren't pleased with the ribbon as the
frequency response tails off; {see chart}

http://www.partsexpress.com/pdf/264-710.pdf

There are some folks who don't care and enjoy it regardless.

Some of the critical ear folks will use the RD as a midrange driver and augment it's
weakness with a 'super tweeter' line array and use the system with less emphasis
on higher SPL. This gets more complicated. The PT2 array is the best solution
for 1/2 the cost as long as you make a big line and wire it for low impedance,
you can get some amazing performance. Individially, the PT2 is not a great
performer, but in a tall line array {8 - 12 drivers per cabinet}, there is 'power
in numbers', SPL can rise, distortion is very low, etc. I have alot of line array
pics on my home computer I can send you for ideas. There are other tweeters
choices that cost 4x more than yield 5% - 15% improvement in sound. To some
folks it's worth it, to others it's not. We can figure this out later. If your budget
is really phat, I have more ideas if you feel like destroying the world.

You can work around speaker design issues, but the best thing you can do is
to define design goals.

You already defined one goal -> I want to simulate a live performance with as much as accuracy as DIY possible. Therefore, SPL becomes a major player in my design considerations.

This is a good start.

If you are still confused about how to achieve this, why not take a trip to various high
end stores and audition as many expensive systems as you can using your music
to calibrate yourself, ie like test driving a car. You need some reference knowledge
in order to build something better. Analyze the systems you audition and take notes.

Did you find something that met your goals? If so, what type of design was it?
If you didn't find something, then you know you need an extraordinary speaker design.
This will come to you over time, I can throw you some ideas, but more data is needed
to know what you like.

If you want more attention, start a thread on the 'other forum' :wink: to expedite
your project.

[Jack Gilvey]

The coloring that the Marshall does is not a bad thing at all. It is what produces the unique sound of a Marshall which is quite different from a Fender Cab.
4x12 cabs cabs are where you can really save some dough going DIY. $750 for a Marshall? Oy.

[Jeremy Snow]

The sound of a vintage tweed cannot be reproduced in a DIY cabinet. Every player has his own unique setup and sound that they have found over the years. The cabinet is a big piece in that puzzle for most. Some muscians spend tens of thousands trying to get their setup right. On the other hand a vintage cello can easily cost a hundred grand. I had a friend in high school, way back in high school who bought a 4x12 cab from a stoner friend of his for $400. My friend didn't know what he had either and traded it for modern cab because the cloth was black. My friend needless to say smoked a lot of pot too.

[Jack Gilvey]

The sound of a vintage tweed cannot be reproduced in a DIY cabinet.
Perhaps, I'm talking about what some of the new Marshalls are going for.