5.1 DIY kit with on PA speakers (or good & small DIY kit with PA speakers) ?

jm_kzo

Member
2008-05-13 1:56 pm
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...
[IMGDEAD]http://jeanmichel.cazaux.free.fr/Albums/Baby Cine/Baby Cine Main.png[/IMGDEAD]

An artist view of an effect speaker...
[IMGDEAD]http://jeanmichel.cazaux.free.fr/Albums/Baby Cine/Baby Cine Effect.png[/IMGDEAD]

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

Member
2003-05-21 2:51 pm
Berlin
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:


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:


actual cinemas use PA stuff

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


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.


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


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.


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. ;)


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.


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!


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?


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.
 

jm_kzo

Member
2008-05-13 1:56 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

Member
2003-05-21 2:51 pm
Berlin
Hi, :D


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... ;)


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:


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. ;)


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

Member
2008-05-13 1:56 pm
Seb,
point taken on board about intrinsic differences between pure PA technologies and the ones used in cinema/theaters.

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.


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/bau_xd120_craaft_en.htm (ditto for 8')
http://www.lightspeed-audio.eu/Entwicklungen/mt-1214/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

Member
2003-05-21 2:51 pm
Berlin
Hi,

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


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...


http://www.lightspeed-audio.eu/Entwicklungen/mt-1214/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! ;)


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

Member
2003-05-21 2:51 pm
Berlin
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).
 

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sek

Member
2003-05-21 2:51 pm
Berlin
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... ;)
 

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jm_kzo

Member
2008-05-13 1:56 pm
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 ;) ?
 

sek

Member
2003-05-21 2:51 pm
Berlin
Hi Jean-Michel,


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".

Hmmm, let me think about it.

Despite the still open question wether a H100 (or anything similar) is the right dispersion flare for the purpose, why shouldn't it fit into your proposed 25cm height of the trapezoidal enclosure you designed? Didn't we find out that even a XT1086 with a DE250 on it would fit into 22cm? ;)

Did I miss something? :confused:


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...

Yes, he's also working on:
- LBT-110 (Delta 10, BMS 4524, XT120): ca. 140€,
- LMT-101 (Delta 10, RCF N350, H100): 210€,
- MT-101 (18s MB600, BMS 4550, XT1086): > 350€,

This guy is really busy and helpful. :)
Unfortunately I don't think he is a member here on diyaudio.com...

A quick research shows that the combination of L8S800, N350 and H100 would come out at 240 Euro without the crossover components.

Andreas Guhde from Cantare Audiosystems posted measurements of the N350 on H100 and XT1086 for comparison, just in case you are interrested... ;)


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

Both, actually. But as the MT-181 is relatively new and demand for a DIY 8" project isn't too large in the PA business, all information I could find relates to the builders from Benjamin's Project log and visitors in his shop.


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

Quite frankly, yes. But that's only in comparison to the other, better quality components we were talking about.

I'm not a friend of the regular Eminence programme (in contrast to their OEM models), but for under 100 Euro I don't think it isn't worth a try. Imagine the two rears being cheaper than a single front speaker. :)

It depends on how much you focus on sound quality with the rears, as they will likely just stay muted when listening to music.


this 8' kit [...] Ever heard about it ?

Nope, and I don't think I ever will.

Manufacturer application notes are reference implementations. No professional manufacturer will simply copy them, and I don't know of any DIYers who build such manufacturer kits without own modifications.


Any opinion ?

Yes, clearly.

Draw up a quick 3D sketch of the room you plan. Position a rear speaker in the corner under the ceiling at the rear end behind the auditorium. What angle does it have to cover in order to disperse the sound equally over the whole horizontal and vertical plane, especially the vertical one? Compare this to i.e. the horizontal and vertical polar maps in the 18Sound application note, especially the vertical one... :cannotbe:

I promised not to rant about it again, so I won't stress that the XT120 is just another PA component unsuitable for HT in this application (i.e. distance, angle). Or will I? :D
Also, Benjamin's MT-181 is a better development, all in all.


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

Maybe it's because we're talking about genuinely European products on an American forum?
C'mon guys, chime in with your recommendations and experiences. ;)

Cheers,
Sebastian.
 

jm_kzo

Member
2008-05-13 1:56 pm
Ok, I told you guys (well...) that I would sched some light on what are our current trend of thoughts, so I am...

When we realised that we were having lots of dificulties findinf an existing DIY kit/plan for the purpose we started thinking about it from scratch.

At first, we thought "8' will be well enough, and lets add a nice little compression that will be smashing!!!"...

When trying to find a 8' that would go low enough (80Hz in 20/25l) with a nice flatish response curve, and that would go high enough to mate with a little compression, there was not many... The RCF L8S800 stood out. Marying him with a little RCF ND1411 on a B&C ME20 horn was looking nice and pretty. On a size point of view, we could make 5 identical speakers (bar enclosure), the budget was really stretched (+/- 245€ per speaker incl. 50€ for the cross over).

But we shared this on forums like this one it was a very different story as it would seem the RCF 1411 is no good below 5k (as most "little compressions"), and obvioulsy no mid woofer would/should go as high as well as going down to 80Hz.

As well, the idea of having an 8' going as low as 80Hz with low distorsion is a bit optimistic (apparently)...

We then reviewed various option incl. going to a bigger compression like DE250 and a 10' for the fronts, but having to account for budget restrictions on the rears... During this brainstorming process, coaxial set up where asd well discussed... We remained with 4 options that we think are valid and worth thinking about, the other being of little interest (because the expected value or value for money is not looking great compare to those 4)... We have given those options "little names" so that we can discuss and identify them easily. It is to note that for each option, the actual drivers are propositions still under discussion. Thier characteristics (on paper), qualities (unfortunately, by hear-say) and prices are what matters. As well cross over is included in budget as well as misceleanous harware (binding posts, etc.) at 50€ per unit. Wood or finish is not.

Ok lets go...

The "Optimum"
A bit emphatic as a name (specialy in this forum), but hey...

For this one a special effort is done on the front speakers so that they cover most of the range and give top sound quality. This has to go with trade off on the rears where we chose cheaper options but keeping same driver brands and flavours...

Front
B&C DE250 + RCF H100 (or XT1086 ;) )
Beyma 10G40

Rears
B&C DE10 + B&C ME20 (or XT120... NOT ;) )
Beyma SM108 or 6G40

Front come at 315€, rear at 190€, total budget for 5.0 = 1325€... We are really up to the limit (slightly above actually, as even with a cheap sub, we are likly to overshoot 1600€), but this looks like the best sound quality. As well, we think we are more likely to find some help with speaker that are quite well known in the community.

Drawbacks/questions :
-isn't it going to be "too much sound" in a smallish room ?
-we need to increase the size to 53cm tall and 22cm depth for the front ?
-are we going to get our bucks back from the sound ?

Other little drawback, but I am not sure it is something we want to consider, if we were to try to do something that will be usefull to others, the "expensive" option is not going to make as popular...


The "El Cheapo & El Cheapo"
Everything is in the title... We try to do everything on the cheap side, prying that it does not impact too much the sound quality.

Front
Eminence APT-150 + Eminence Delta-10
OR Monacor MHD-152 + Monacor SPA-25PA (Sebastian ?)

Rears
Eminence APT-150 + Eminence Beta-8
OR Monacor MHD-152 +other Monacor 8' or same 10' if we can fit it.

With the Eminence drives, budget is down to 740€ for 5.0 (up to 870€ if we replace the ATP-150 by DE10+ME20)... Still some money, but 60% of the previous option.


Drawbacks/questions :
- Is it going to sound "half-good" the Optimum option, worse or better than this ?
- SPA25-PA might not be happy with "just" 25l...

Good point is that if we ever succeed making quite decent sound quality with this, it can be quite popular (and we have contributed foir the community !!!).

I am surpised that we have not found existing kit (excatly x-over design) using MHD-152 (or similar)+SPA25-PA, but we have not.

Note, vertical directivity of the MHD-152 might be a problem, but Monacor has other horns similarly priced...


The "Coax-B"
This is a coaxial set up using Beyma 8CX20. One French well known provider of PA/Hifi loudspeakesr and kit made one loudspeeaker with it and it had very good reviews (unfortunately, not sold as a kit).
Caoxail drivers are apparently better for directivity and "sound coherence" but come as well with "a pair of compromises" (lack of real horn, moving cone used as horn, so cannot move this much, just repeating what I have read here and there).

Not many questions except "is it going to sound really good ?" and main drawback is that it is not only one world we do not know (PA & HE), it is as well coaxial speakers.

Budget would be around 1180€ for 5 of them, so not sure there is a massive edge compared to "the Optimum"...


The "El Cheapo-Coax"
Same soup different flavour... and a lot cheaper. The idea came from this CT235 kit from German magazine Klang+Ton (it is to note that CT stands for "Cheap Treak" which seems here a well deserved name). It can apparently by sourced for 139€ each including filter which brings the 5.0 set at a very affordable 700€.

Questions marks :
- quite a few about sound quality ?
- the same about coaxial drivers...
- will it work in 25 litters...


The first option I spoke about (RCF L8S800 + RCF 1411) is probably not worth considering seriously now as it comes out at 1210€, quite close to the optimum package with too much question marks around mating the 1411 to the L8S800...

So these are about the options and to be honest, I am not too sure about the coaxials (but still keep them as some says "it is simpler")... So we are more or less left with "The Optimum" or "El Cheapo & EL Cheapo". It is to note that I have heard good revies about the Monacor/IMG SPA-25PA which apparently has a very good value for the price.

Ok, that's about it fore now, and more than enough food for thought for us...
 

ttan98

Member
2006-04-04 11:24 am
Melb
Beyma Drivers

Hi,

I am writing from Australia, I am trying to buy some Beyma drivers from Europe. Some of the places I tried either don't want to sell me or charges too much for postage and poor service.

I wonder anyone here is willing to help me to purchase these drivers. To reduce your risk I am willing to pay you first prior to you placing an order.

Before we proceed further anyone interested please email me, you can get my email address from my profile.
 

sek

Member
2003-05-21 2:51 pm
Berlin
Like, over the weekend... ;)

It's been like 450 viewers as of this writing, so maybe you're up to something new on this forum!

First of all, what's to say against the L8S800? You seemed to like it in the beginning. Of course it's not like a 10" punch and maximum sound pressure, but we're talking home cinema loudness levels, not concert grade. It's pricey, but comparable 10"ers are, too! :smash:

Second of all, you didn't mention the nature of the installation yet. Will it be fixed (as in non-moveable) or semi-fix (as in moved out occasionally for seasonal parties)?

And third of all, what's the requirement set you're ultimatively aiming for? I had casually mentioned THX and the like. Did you set qualitative and quantitative goals for the essential things like SPL(max), coverage angles, rear speaker configuration, etc.?


The RCF L8S800 stood out. Marying him with a little RCF ND1411 on a B&C ME20 horn was looking nice and pretty.

With the ND1411 you cannot use the same type of horns. Take a look at the frequency response graphs in it's datasheet and in that of, i.e., the N350. The ND1411 is missing an octave or more (on the HF101), and the L8S800 is not a true midrange driver to compensate for this.

You know that (as you write further down). ;)
So how about using a combination like L8S800/N350 only in the front? Saves overall money and improves the quality of the whole system (as the three front speakers are the only relevant sound sources for perceived tonal quality for music and most movie content) compared to resorting to something less good in all speakers.


The "Optimum"

[...]

-isn't it going to be "too much sound" in a smallish room ?
-we need to increase the size to 53cm tall and 22cm depth for the front ?
-are we going to get our bucks back from the sound ?

The Beyma 10G40 is a very well regarded 400W woofer. Five of them inside a room is definitely overkill. It's advantages over the L8S800 would be more bass (which you don't need) and higher SPL(max) (which you don't need, too). And it's around 30 Euro more pricey and requires more box volume than, i.e., the L8S800.

Together with the DE250 and the H100/XT1086 you could get a high-end compact PA solution, but you won't get your bucks back inside your home cinema, as nobody can see the pricey components (or appreciate their superior sound and distortion quality below around 130db(SPL) total inbetween the five boxes). :D

It'll be just "too much sound", yeah! And I don't even consider it the optimum, btw. ;)


The "El Cheapo & El Cheapo"

[...]

- Is it going to sound "half-good" the Optimum option, worse or better than this ?
- SPA25-PA might not be happy with "just" 25l...

I am surpised that we have not found existing kit (excatly x-over design) using MHD-152 (or similar)+SPA25-PA, but we have not.

Monacor components can be surprisingly better than expected. I have no doubt that a Monacor horn and midbass speaker can also be good. It will certainly be close to the above idea at low and medium SPL.

I know of some projects and kits using SPA 12" speakers, as this is the more demanded size for PA tops and small fullrange boxes, but none with the SPA25-PA either.


The "Coax-B"

[...]

The "El Cheapo-Coax"

Good coaxial PA speakers are available from some manufacturers, namely the already mentioned Beyma, B&C, RCF and Monacor. Again, the questions of SPL(max) and coverage angle arise.

If the lower excursion limits of coax speakers don't become a limiting factor, they can be a very good idea for a multichannel application. But a couple of drawbacks come together, some already mentioned by you: dispersion, lack of true horn, intermodulation, impossibility to go bipolar, etc.

Are you aware of the Adire HE10.1? I think Dell's, D’Appolito's and Colin's review sums up all advantages and disadvantages of such a construction.

The review also shows that K+T's CT235 was no innovation, as the HE10.1 is from 2001. But maybe the K+T crossover is an improvement, as it also uses a different tweeter. I can't tell. ;)


To sum it all up, rent some good PA speakers and turn up the volume, get the goals set, consider high quality in the front and the right dispersion in the rears, don't forget the bass requirements and don't hesitate to combine different manufacturers (i.e. how about Monacor's SP25-PA with 18Sound's XT1086 and B&C's DE250?). :cool:

If I were to do it with what I know about your goals, I would consider Benjamin's MT-181 with the N350 in the front and the CT235 for the rears. But I don't think the goals are set for this already. ;) Or are they?

Cheers,
Sebastian.
 
In my original post,I was going to mention the Adire HE10.1,but to the best of my knowledge,they are no longer available.:-(

I am using a pair for my surround speakers in my HT system,(front is 4 way front loaded horns)and they do a very respectable job for an inexpensive speaker.I think 5 of them would do well for a system that meets your size and price requirements.

The woofer is a Eminence beta 10cx,and the compression driver is a modified Eminence APT-50,I believe.Not sure what the difference is from the stock version.You could use a different tweeter,but then the crossover would probably be needed to be changed,so then you would have a different speaker...

Anyway,the size would be very close to what you need.You can change the box dimensions,as long as the internal volume stays the same.

The Eminence Beta 10cx,APT-50,and the PXB2-3K5 crossover is about $135 USD from partsexpress.com ,plus shipping.If you don't want to risk any more than necessary,just start with one of each to build one speaker,and if it is acceptable,you could get four more.

Of course,a subwoofer is going to be needed.IMHO,a tapped horn will provide the most bang for the buck.Yes,they are big,but can be put in a corner,or placed down on the floor.

here's another link to the plans for the HE10.1

http://stereointegrity.com/Files/HE10-1Plans.pdf
 

Don Bunce

Member
2007-03-21 3:55 pm
I forgot to mention in my previous post that a way to keep the cost down without sacrificing quality is to not use a center channel.(you can add one at a later time if you feel you must)

I have yet to hear a center channel that I thought improved the sound over using the phantom mode.The center speaker needs to be identical to the left and right speakers,(most aren't)and there is generally no way to place it properly,unless you have an acoustically transparent screen,with the speaker placed behind it.

If you don't have a front projector,you have no choice but to place the center speaker above or below the picture.The larger the screen,the more it has to be off set.Strange to hear voices coming from the ceiling...or out of the floor...

Anyway,that's my opinion,and something else to think about...