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-   -   5.1 DIY kit with on PA speakers (or good & small DIY kit with PA speakers) ? (http://www.diyaudio.com/forums/multi-way/122996-5-1-diy-kit-pa-speakers-good-small-diy-kit-pa-speakers.html)

jm_kzo 13th May 2008 03:49 PM

5.1 DIY kit with on PA speakers (or good & small DIY kit with PA speakers) ?
 
Dear audio DIY enthusiastic,

I am coming to you with big expectations as I have been trolling the web for a while now and I am a bit desperate to find what I am looking for.

I am currently building a small dedicated home-cinema/hifi room. It will be roughly 3m x 6.5m, built according to a live-end/dead-end schema with absorbent ceiling (rock wool).

As I was wondering about the speakers, I thought it might be a good idea to try something based on PA "technologies". I must confess I never heard such system in hifi/DIY conditions, but the reasons behind this idea are:
- actual cinemas use PA stuff;
- high end home cinema kits use PA stuff (Klipsh, JBL, GKF;
- from what I read PA speakers/high efficiency systems are more likely to reproduce the "liveliness", high dynamic, great sound impact, "clear and accurate sound" ... (quite hard to express in English) necessary so as to reproduce soundtracks.

We can currently find a Jamo D6 5.1 pack in France for around 1300€ which setting up the mark for both sound quality (no doubt it can be done) and the budget (introduces a stringent constraint!), but I must admit that I like the DIY thing and I'd like as well to discover the world of "high efficiency" (even if it is not that high ;) ).
Another friend of mine is going to go thru this process soon as well and joined me in my quest.

The other requirements of the system would be (more or less in order of importance) :
- front speakers cabinets should fit in 50x50x20 (roughly). I have made a little 3D "simulation" that you can see below. Often better than a long description... Speakers are a 8' and a DE10+ME20 horn, to give a sense of sizes and shapes. I have as well modelised it with a 10' and a DE250+H100 horn, and it is as much as we can fit in the box without over shooting too much the limits (becomes 53 tall and 22 deep).
- the rear speakers will be wall mounted (up to the ceiling) and will "down fire". Simulation below as well (using same speakers). 10' and H100 are not an option here.
- we are looking for great dynamic, great sound impact, "clear and accurate sound" (all this is quite hard to explain in French, but even more in a foreign language, sorry).
- The main speakers should go as low as possible towards 80Hz where a good sub woofer will start action (but just for sub bass).
- this will be driven by a "traditional"/mainstream home-cinema amplifier (7x100 in my case).
- we'd very much like to maintain the budget for the 5.1 configuration to 1500€ (incl. speakers, components for filters, subwoofer amp, misc. hardware but not wood or finish). If we want to keep 150€ roughly for the sub woofer loudspeaker and 150€ for the subwoofer amp, this leaves 1200€ for the 5 speakers = 240/250€ average per speaker.
- as much flat response curve as possible.
- this is to be used in quite small rooms (about 20m² and possibly 27m² as a friend of mine who could be interested as well).
- if the front speakers are really good, they will be used for hifi as well (driven by WAD 6550 tube amp), but this is not a priority.

An artist view of a main speaker...
http://jeanmichel.cazaux.free.fr/Alb... Cine Main.png

An artist view of an effect speaker...
http://jeanmichel.cazaux.free.fr/Alb...ine Effect.png

As I speak (or write) we have not found an existing DIY kit yet that would fulfil these requirements or even come really close, so we are reviewing starting from scratch but as my electronic knowledge is limited to U=RI I am a little bit weary about the cross-over design, (fortunately, my friend knows a bit of electronic).

That would be really great if one you came across a design available on the web that would "fit the bill" or at least can be easily re-engineered with reasonable chances of success.

Many thanks in advance for your hints and advices.
PS : Sorry for this long post.
PPS : Sorry for my Frenglish, I am doing my best.

sek 13th May 2008 10:02 PM

Re: 5.1 DIY kit with on PA speakers (or good & small DIY kit with PA speakers) ?
 
Hello Jean-Michel,

well, this will take me some time to answer, phew...

But I like the idea. :cool:
Let me just step through your remarks and questions, commenting them on the fly:


Quote:

I must confess I never heard such system in hifi/DIY conditions
That's easy, go and rent a (pair of) Nexo PS10 (including neccessary cabling, but excluding the recommended controller or system amping; too expensive) for a weekend. It's worth it. Mention that you don't want them for a sound reinforcement venue, but for an audit session in order to evaluate a future buy. :D

You could get totally different ideas from the experience than you would expect. But accomplishing such a project without gathering an impression on the sound that can be expected beforehand could be very misleading during the course of spending the money... :bigeyes:


Quote:

actual cinemas use PA stuff
Actual cinemas use cinema stuff. Many professional sound reinforcement speaker manufacturers also have a cinema line of products.


Quote:

high end home cinema kits use PA stuff (Klipsh, JBL, GKF)
Companies like Klipsch or JBL also manufacture Hifi, Multimedia, control room, A/V and general purpose speakers. Those are never the same as the PA speakers. They usually also come from different departments inside the respective company.

While you're at it, rent a JBL Control One together with the PS10 in order to compare.


Quote:

from what I read PA speakers/high efficiency systems are more likely to reproduce the "liveliness", high dynamic, great sound impact, "clear and accurate sound" necessary so as to reproduce soundtracks
That's a subjective impression. And I share it. :D


Quote:

front speakers cabinets should fit in 50x50x20 (roughly)
That's a very shallow depth! I don't think you could even fit a regular driver/horn combination in, let alone the better of the following ones.


Quote:

DE10+ME20 [...] DE250+H100
Funny thing: from looking at your pictures I thought: Man, that could be a B&C horn. Before reading the text. ;)


Quote:

The main speakers should go as low as possible towards 80Hz where a good sub woofer will start action (but just for sub bass)
This is possible but difficult, as the usual 8" or 10" midrange PA drivers have very limited excursion capabilities (Xmax) and won't keep up with their own upper midrange sound pressure level at frequencies below around 120Hz.

One way to achieve this goal would be equalization, so that the maximum sound pressure level is traded for a lower frequency limit. This approach is possible in your installation because you don't require the midrange drivers' full SPL capability in your (relatively small) room.


Quote:

If we want to keep 150€ roughly for the sub woofer loudspeaker and 150€ for the subwoofer amp, this leaves 1200€ for the 5 speakers = 240/250€ average per speaker.
This is tight but possible on the five speakers.

Unfortunately it's impossible on the woofer.

In order for a subwoofer to keep up with three 8" (or even 10") midrangers in the cinema front, you'd need at least two drivers in the 15" or 18" class, depending on your SPL desires.

You could get away with 12" bass drivers and clever use of the room modes, though. But you would be surprised by the demand of a powerful LFE channel!


Quote:

as much flat response curve as possible
At what planned average and maximum sound pressure levels? Did you read the THX or DTS specifications regarding the demands of SPL and directivity?


Quote:

if the front speakers are really good, they will be used for hifi as well (driven by WAD 6550 tube amp), but this is not a priority
I'd say this is easily possible and good sounding with such an A/V installation. I explicitly recommended the Nexo PS10 because of it's very good sound quality. You could compare their sound to your regular hifi speakers (supporting the PS10s with a very powerful subwoofer), but be ready for some impressive experience. Note that you wouldn't be able to copy the PS10 (neither in tonality, nor in build quality) within your budget, but they can give you the idea.

All in all this sounds like a fun and interesting project. And a lot of future visitors once it's finished. :D

Cheers,
Sebastian.

Don Bunce 14th May 2008 03:59 AM

For the bass,I would recommend a tapped horn,see the Collaborative Tapped horn thread in the subwoofer forum.

jm_kzo 14th May 2008 01:13 PM

Hi Sebastian and Don,

first many thanks for your replies (even if they do not point at the Holy Grail I am looking for ;) )...


Sebastian,
yes, renting is possibly an option to be able to hear what the world of PA and high efficiency can deliver... I probably need to look into this before making a "step".

When I was talking about "PA stuff" in cinemas, I know they do not use actual PA speakers, but more PA technologies (AFAI can say, high efficiency, compression tweeters, horns, etc.).

On the same line, when I mentioned Klipsh and JBL it is for their use of PA technologies and solutions in their high end HT sets (have a look at JBL Synthesis Onehere or Klipsh RF sets here).

Re the "shallow depth", I have already done a bit of homework and you can actually fit a B&C DE250 compression + H100 horn in 22cm (19mm "wall"), so not far from 20 ;).

The size constraint also brings a "little volume challenge" (max. 25l net) which is restricting the usable loudspeakers as well.


Yep, we think the woofer is going to be challenging with 300€ for both the driver and the plate amp... We were thinking going the El Cheapo option here (provided front speakers can make it down to 80Hz) with a Dayton DVC-15 and a Bash 300 amp (or something in this league)... Should be good enough for sub bass in movies (we would think).


Don, this looks great and I trust it produces a lot of bass, but WAF is close to 0 isn't it ?
Is ther tapped horns with "reasonibly sized" enclosures ? (40 x 60 x 80 max... centimeters, not inches ;) ).

I will post something with our current trends of ideas soon... But still which to find something that has already been implemented by someone ;).

All the best, thanks again for "playing ball".

sek 14th May 2008 03:03 PM

Hi, :D


Quote:

first many thanks for your replies (even if they do not point at the Holy Grail I am looking for ;) )...
Oh, I thought by leaving out any kit recommendations it was clear that I'm not aware of any... ;)


Quote:

When I was talking about "PA stuff" in cinemas, I know they do not use actual PA speakers, but more PA technologies (AFAI can say, high efficiency, compression tweeters, horns, etc.)
I see what you mean, although I make a clear distinction between cinema and public address systems, though the same principles apply.

The reason I'm doinig this is that the question what has been there first - high efficiency public address systems or high efficiency theater systems - is not an easy one to answer... :att'n:


Quote:

On the same line, when I mentioned Klipsh and JBL it is for their use of PA technologies and solutions in their high end HT sets
Okay, let me make myself clear about this before it's too late. I'm gonna shut up right afterwards, I promise! ;)

Putting a compression driver onto a horn is not intrinsically "PA technology".

Furthermore, compression and horn technologies (in any band, not just high frequencies) used to be developed back in the days of low to medium power amplifiers and high driver cost. They are not an outcome of modern PA "research". ;)

The reason why I insist on the difference between PA and cinematic use of the components is because the components usually get developed (dispersion characteristics, power distribution, bandwith) specially for the purpose. The resulting sound reinforcement systems in total are definitely unique to the purpose, as you can see from their looks and measured response (i.e. club sound vs. life sound vs. THX specification).

The examples you mentioned (JBL Synthesis, Klipsch horns for home theater) use decades old sound reinforcement ideas in a very modern way, but they are not neccessarily using PA technology, as you can see in the "Synthesis One": neither the "UHF transducer", nor the "HF transducer", nor the 8" LF transducers are PA technology. Those are especially developed for A/V purposes, they just wouldn't make sense in a concert situation (i.e. large hall, wide stage, etc.).

The woofer (JBL 2242 HPL) in their Synthesis system on the other hand is one of the best PA woofers out there.
So there is a close connection between the markets for PA and cinema sound, which we both agree on. :D

My point simply stands as it is: just selecting some PA components and expecting good sound in a home cinema enviroment can easily go wrong, especially in the dispersion (coverage angle, interference between multiple horns in proximity) department.

But I'm not here to instruct or correct anyone, that's why I promised that this rant will be over ... right ... now. ;)


Quote:

you can actually fit a B&C DE250 compression + H100 horn in 22cm
Yes, I recalled a different horn depth on the H100 (which is silly as I'm having one lying next to me). I can even fit an 18Sound XT1086 with a Beyma CP350 or RCF N350 into 20cm. My bad. ;)

BTW, all of the three drivers (DE250, CP380, N350) seem to work better on the XT1086 than on the H100. You find this 18Sound horn mentioned in HT forums very frequently.

Other than that, I'm interrested in what the two of you will come up next. :cool:

Cheers,
Sebastian.

jm_kzo 14th May 2008 04:50 PM

Seb,
point taken on board about intrinsic differences between pure PA technologies and the ones used in cinema/theaters.

Quote:

So there is a close connection between the markets for PA and cinema sound, which we both agree on.
This is exactely what we think as well and why we find this an interesting adventure.


Quote:

My point simply stands as it is: just selecting some PA components and expecting good sound in a home cinema enviroment can easily go wrong, especially in the dispersion (coverage angle, interference between multiple horns in proximity) department.
This is what makes the "interesting adventure" risky and sometimes scarry (and sometimes the temptation to go for a commercial pack is big).

I read good things about the 18Sound horn, but they do not seem to be easy to source in France...

As you are from Germany, I wondered if you heard about these kits :
http://www.lautsprechershop.de/pa/em8bet_en.htm (not sure 8' will be enough, but this one is really cheap)
http://www.lautsprechershop.de/pa/ba..._craaft_en.htm (ditto for 8')
http://www.lightspeed-audio.eu/Entwi...14/mt-1214.htm (on the expensive side and a H100 will not fit on the rears, but still a track)...
http://www.lautsprechershop.de/pa/d2544_k12_en.htm (a bit too big and a bit too expensive, but...)

Those one need an enclosure re engineering, but except this, they fit more or less the bill... Just that we have no idea about sound qualities.

sek 14th May 2008 09:34 PM

Hi,

unfortunately I haven't heard any of the combinations, but I know most of the involved components.


Quote:

http://www.lautsprechershop.de/pa/em8bet_en.htm (not sure 8' will be enough, but this one is really cheap)
I think the quality just isn't right...


I think the price just isn't right...


Quote:

http://www.lightspeed-audio.eu/Entwi...14/mt-1214.htm (on the expensive side and a H100 will not fit on the rears, but still a track)...
I think this one is just too powerful and oversized, it's intended for 200 to 400 people.

The developer, Benjamin Jobst, is a known resource in the German DIY PA scene.

He usually gets inspired by discussions and demands on German PA forums. Such was the case with the MT-1214.

But he also developed an 8" version in the same line of component and sound quality, the MT-181, which got very good reviews.

The current talk, BTW, is about different 10"/1" versions, using either RCF, B&C or 18Sound speakers, drivers and horns. He's working on it! ;)


Quote:

http://www.lautsprechershop.de/pa/d2544_k12_en.htm (a bit too big and a bit too expensive, but...)
I think you're right, it's too big and too expensive (like the MT-1214, just not as good)...

Cheers,
Sebastian.

sek 14th May 2008 09:47 PM

2 Attachment(s)
Here's a comparison between the H100 (green) and the XT1086 (orange), done with the aforementioned Beyma CP350/Ti.

As can be seen, the H100 is a little problematic around it's cutoff frequency, the XT1086 looks a lot smoother here (and sounds less rough, too).

sek 14th May 2008 10:03 PM

2 Attachment(s)
And this is the response filtered at 2kHz (red) using a Linkwitz-Riley alignment.

With some EQ (green) the thing is down -6dB at 2kHz and 16kHz with a +/-2dB response inbetween. :cool:

The bump around 6.8kHz is a measurement artefact (or caused by the CP350).

Proper equalization gives a similar response for both horns, with the XT1086 providing the better sound, as per my subjective impression... ;)

jm_kzo 15th May 2008 07:07 AM

Sebastian,
you are right re the MT-1214... It is not the one I was looking at... Just f**ked up when copying the link. The one in Benjamin list that is interesting is the MT-181.

The issues I saw here are around budget (they are on the high end of the scale) and they cannot be used for the rears (an 8' will fit, but not a H100 horn... This would require designing anoter "rear" with eventually the same 8' but a smaller and as well cheaper compression... almost as challenging as the "full thing".

I was actually in touch with Benjamin and he told that he is working on a version of the MT-181 with an RCF N350 compression which according to him would be more hifi...

When you say it had good reviews, in what context was it (pure PA or home hifi as well) ?

As well re the el Cheapo kit from lautschprecher shop, when you say quality is low, you think it wçill "translate" in sound ?

And finally another suggestion, we came accorss as well this 8' kit from 18Sound. In the version using a ND1020, it is a bit on the up of the budget (highest option we are reviewing actually), but at least we have everything here we need (basically, the xover schema)...

Ever heard about it ? Any opinion ?

Thank in advance.

PS : why are we just on our own ;) ?


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