Help needed first 2 (3) way with a compression driver for LCR home theater

Hi All,

I posted this also on AVS Forum, but doing my research I noticed a lot of topics exist on diyaudio on the subjects I was looking into, a lot of expertise.

Application: Home Theater, LCR speakers. Will be used with (already existing) subwoofers for the low end (<80Hz). I will mount them to the wall, and would like them to be about 12" or 30cm deep (preferably) so I can put a acoustic transparent screen in front of it should I want to turn my living room into a cinema at night.

Budget: flexible, but would like to be between 2-3k EUR for the drivers (probably 3k), crossover, horns and DSP. Amplifiers I have plenty, wood construction I have all the tools already from previous subwoofer builds

Experience: Built some subwoofers, sealed and vented, using WINISD, but no experience with crossovers (except integrating my subs with miniDSP and REW using a Behringer mic) and 'speaker stuff'. Read a lot about lobbing, beaming, ... but total Noob in designing or making them.

Space: I would like them to be about 40cm wide, 180cm high and 30cm deep, which is about 150L of volume taking some bracing and the woofers into account. I could always go wider or less high or whatever is needed. the idea is to build 'around' my 70" TV 3 cabinets (LCR) which look like actual cabinets not like giant speakers (WAF factor)

Room: Part of the living room, it's an L shape room, I'm around the corner in a space of about 4,2*5m with a height of 2.8m. The total area of the open space living room is about 80-100m2 depending if you count the veranda or not. The speakers will be at a distance of about 3,5 m ear-to-speaker level so quite close. A lot of windows in our living room, very challenging.

Sound: I like planars and ribbons, actually I still regret having sold my infinity renaissance 90 speakers but I don't like the price, the age (!), the efficiency, the spacing from the wall and limited dispersion. Would like this real 'cinema' feeling, thumping mid bass which you feel in the chest, and crisp highs which makes you think it's raining inside and get every detail in the highs. I have sensitive hearing, I hear things I shouldn't hear such as those high frequency mouse repellers. So would like to have something which goes without too much distortion to 20 kHz. I don't listen at crazy levels

Low end: i'm kind of decided I would like to use SB Audience 12MW200 (2 pieces per cabinet) as they are cheap and in a vented 130L cabinet tuned to about 46Hz they have a very nice curve in Winisd, the top end looks also good from the mfg data. It would be 200 EUR for 2 drivers, so pretty cheap. If it's a bad decision, please let me know, but I'm trying to decide some stuff to avoid I stay in the analysis paralysis.

mid end high end: Initially I though about a coaxial, as they use in the famous JTR speakers, crossed over at 500-700 Hz. The 12" beams at about 1150 Hz so would like to crossover well below that. All of the below can be had for about 400 euro a piece (without crossovers for the coax which adds to the cost...)
  • BMS 4590: proven 2" technology but has it's issues
  • B&C DCX354: got recommended the most, gets good reviews, has a good extension, it's 1,4" though which complicates finding a really good horn (?)
but as I kept on investigating, some new CD's also claimed to have a low extension with a 'hifi' sound as they use more novel materials compared to the 'hard' titanium
  • Eminence textreme n314x
  • Faitalpro HF1440
the upside of these CD's is I don't need an extra crossover as with the coaxials, the downside is I have the impression they don't load that well below. I was almost decided on the DCX354 but after reading (too many) other topics I'm thinking the other options are also viable for my application.

THE HORN: this I find the most difficult. The CD's mentioned above all seem to be capable, I can also apply some DSP to correct, but the horn seems to me the most important as I need low distortion, a high dispersion and also a good extension for the low and the high end, without having a huge ME64 horn, which would blow my budget and the WAF factor.
I thought about the below horns:
-18Sound XR or XT1464
  • RCF HF950
  • Eminence H14EA
  • 2": BMS 2230 or ME75 though they are much more expensive and I need an adapter

At the moment, I think about the RCF HF950 with the n314x or the DCX354. The thing holding me back on the n314x is the crossover point, I read in a topic it should be 1000Hz, but on the upside it's cheaper and easier to integrate compared to the DCX354 (but only cheaper by about 100 euro a piece incl crossover)

I started from the JTR's for inspiration, but maybe I'm completely 'off track' and over thinking it, or over spending on it, so any help is really appreciated to get out of this analysis paralysis
 
With CD's working down to 800 hz at home volumes, I really don't see the point of 3 way designs with a 5-6" cone midrange. I've studied the N314x and it's main downfall is 15-20 khz response is down 5 db. It is really superior among 1.4" CD for producing 150 W AES, but you don't need that much volume in a home. Balanced 54-14500 hz sound can be produced with 70 w Peavey RX22 1.4" CD up to 500 w AES. I own these in SP2(2004). I can't hear above 14 khz, but if your ears are really good to 20 khz, you might want a 3 way 12" woofer, 1.4" CD, 1" cd, and cross the 1" above 14000 hz. There are also various other tweeter designs for 14-20 khz that are much smaller than a horn. If you do want the H14ea horn, buy now, they are discontinued and Part-express has already dropped them. I bought mine at usspeakers. The entry angles to any horn are undocumented and I bought real eminence instead of paudio from thailand because unmatched entry angle can cause problems. I was also looking at $50 horns from miami (ebay) but some poster here had trouble with that vendor's packaging. The peavey SP2(2004) horns are really superior with built in assymetry to project the sound down at heads from 10' high, but they are threaded 1 3/8" mount and unsuitable for a bolt on CD.
My Peavey SP2-XT were stolen and the replacement SP2(2004) are visible from the street through my windows. I want to build a really ugly pair of speakers that will not be stolen. I bought N314T which doesn't have as much volume as N314X but a smoother top end. I listen mostly at 1/8 watt and never go over 70 watts for both drivers indoors. I have Deltapro-15a for woofers, and am agonizing over the woodwork to package them. I will not address 14 20 khz since I can't hear it. I don't have a problem with titanium drivers; I think maybe the complaints about distortion are at high volumes where I never use my speakers. There are limited selection of demonstrators in the Louisville market, but the SP2(2004) 2 ways are the best speakers I have heard. I test with Steinway piano tracks including bottom & top octave, also tinkly bells & percussion which I have also heard live.
 
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Thanks a lot for your quick response.

Maybe to clarify myself, with a 3 way I was referring to using a coax + 12" woofer, as I need a 3 way crossover, while a 2 way would be a normal CD + 12" woofer. I indeed do not intend to use a dedicated midrange also as I like the idea of having a points source for the higher frequencies, as based on my limited understanding so far, higher frequencies are much more directional with a much narrower dispersion compared to lower freq. Again, this is just my noob opinion based on what I learned so far.

Indeed, the n314t uses Titanium, which is one of the reasons the n314x is being 'hyped' so much as they use textreme which gets also . The 4590 uses Polyester (so they don't have the titanium sound either?) and the dcx354 uses 'polymer' which sounds to be similar to the 4590. Honestly I have no clue if this is really important. As I'm not as interested in max SPL I don't need the latest word in efficiency but the least distortion and the smoothest flattest curve.

https://audioxpress.com/article/test-bench-eminence-n314x-textreme-compression-driver
https://audioxpress.com/article/tes...-8-with-h14ea-horn-and-n320t-8-with-h2ea-horn

The n314x seems to have good extension even +20kHz but not sure if it's really as simple as adding some EQ as also the horn has to be able to cope with it? This really confuses me, the combination horn + CD and how to eq them. I drew a line below, this is all pure theory, so not sure it's that easy to just eq them down in minidsp to get to this flat curve:

eq'd to 95db it goes from 400-25kHz. Nice but my woofers down low have a sensitivity of 95db but can take 400w total, so this will bring down the whole system

n314x eqd.JPG



eq'd to 100, goes from 500 to 20kHz, which should be plenty

n314x eqd 100.JPG


DCX354 eq'd to 100db (doesn't make sense to do 95db as I will not gain any top end). Goes from 300Hz to 20kHz, so a crossover at 600Hz would be an octave above the dropoff, so seems good to me?

DCX354 eqd.JPG


All of them have more than enough SPL for me not to worry too much about the extension to 20kHz, they can be eq'd down and all reach it, it's the bottom end mainly.

It's quite overwhelming tbh

questions:
  • How important is the material of the diaphragm, is textreme or polyester or polymer important or should I just look at the waterfall, freq response and other graphs?
  • If I want to crossover at 700 Hz (which I do) do I need a flat response to 1 octave below or is to 500Hz just fine?
  • how much of a factor is the horn in all of this? Are the yellow 'eq' curves I drew up top realistic or total bs as the horn response is fixed and can not be corrected?
  • What will be the effect on the off axis response if I eq down in the mid part? will it beam less or more?
  • Coming back on all of the above, is the n314x a good solution for my needs?

Thanks a lot and apologies for any stupid questions or misconceptions and pure idiocy which are linked to my 'noob' status
 
It is usual to roll off tweeters above resonance 12 db/octave or more, as they can be damaged by too much excursion in the resonance frequencies.
Woofers can be rolled off 6 db/octave to prevent cone breakup, but 12 db/octave is what I am listening to in my music room. SP2(2004) crosses over at 1800 hz. That is rather high for 15" woofer but Peavey made the case trapazoidal with a narrow back to extend the horizontal dispersion. Previous SP2-XT crossed at 1200 hz with a parallelapiped case and 300 watt rating (limited by the 70 w tweeter). 1985 SP2 crossed RX22 to 15" at 800 hz, and had a 175 watt rating.
If you can boost 15-20 khz by 5 db with bi-amp and a dsp, then the N314x should do well in a house. I'm entirely satisfied with the sound of the SP2(2004) but their high cash value at any pawn shop or flea market means they may disappear some day, along with a broken window or door.
The H14ea horn is specified at 60x40 degree dispersion, so unless one is a recording engineer in a 6' deep room that should be enough dispersion for any music room. Beaming can occur above the wavelength of woofers, but the wavelength of 12" is about 1150 hz so should not be a problem with a horn producing 20000 to 800 hz. I do not know why one would want to use a H2ea horn with a 1.4" exit tweeter. Sharp edges can lead to diffraction effects.
Some people are passionate about beryllium diaphragms, or polyester, or anything but titanium. As I have said, the titanium diaphragm RX22+1508-8 woofers are the best speakers I have ever heard on top octave piano tinkly bells, brush cymbals. I am quite annoyed by distortion by reproduction of instruments I have played personally. I have heard a poly diaphragm in a used Peavey 1.4" CD+horn from the nineties, and I did not hear anything special. I have heard Meyersound range size boxes at Brown theater, which has I don't know what tweeter but they are expensive. I found the violins screechy, although the recording of Swan Lake could have been at fault. I also listen to rock/pop music and bluegrass on my speakers, but with electronic recording one has no idea what the original was supposed to sound like. String instruments like acoustic guitar and mandolin are not demanding of speakers, being between 500 to 6000 hz. The top and bottom octaves of a Steinway piano are very special, and very difficult to reproduce with any accuracy. I've owned various failures of speakers at this task over the years. Certainly the Yamaha & Bose PA speakers at various churches I have attended have been miserable failures at reproducing even the *****y yamaha console piano they had.
I would find 700 hz crossover of a N314x violates the recommended 800 hz lower limit. If using passive components, I would start cutoff at 1000 hz, to avoid very high component charges of 24 db/octave filters. As I said, the 12" woofer doesn't beam until ~1150 hz. I prefer passive crossover to biamp+dsp to avoid running 2 or 3 stereo amplifiers 14 hours a day. There is such a thing as global warming, and I use my hifi system a lot of hours. More amplifiers means more air conditioning load, also. Also dsp means replacing it every 5 years or so as cell phones update and the driver software for the dsp becomes obsolete.
 
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I currently use freestanding horns for watching TV. I like them a lot because they are highly intelligible with spoken dialogue so I'm not trying to move you away from horns. I'm just showing you these coaxial silk domes as an example for home theater. Even though these speakers are designed for music they require use of a subwoofer (i.e. like a home theater typically uses). They are able to reach 110 dB with a silk dome tweeter. They are coaxial so all vertical listening axis are good but the BEST listening axis is tilted down a bit so Sigberg angled the enclosures back a touch (for music listening). But in a home theater if you built them as regular non-angled enclosures the BEST listening axis of all the good listening axis would point down to your seated listening height in front of a TV.

SBS.1-white3_feb51208-664e-4558-92dc-d916d1ec9d3e_900x.jpg

https://www.sigbergaudio.no/products/sigberg-audio-sbs-1-aktive-hoyttalere

My free standing horns are just a little narrower directivity than these coaxials. However, I don't wall mount my freestanding horns. I pull them out and toe them inward. Neither are they very WAF friendly. Pretty darn ugly, actually. Obviously, that doesn't work in your situation. But these little Sigbergs are able hit 110dB (low distortion) because they offshored the low frequency heavy lifting to subwoofers by design. They aren't designed as speakers to maybe or maybe not use with subs. You must use subs. Tricky to convince audiophiles to do that but home theater guys love subwoofers. He achieves the low distortion through a 2.5-way configuration and locating each driver in its own small chamber within the larger enclosure so the woofer cones barely move, maxing only about 2mm by 100Hz near to their low frequency cutoff. Granted, he uses expensive DSP Hypex amplifiers in them. The depth of his enclosure is used to control directivity in a bookshelf on speaker stands situation while also housing the Hypex.

Anyway, I'm using these little Sigberg speakers designed for music as an example of the advantage you have when building custom speakers for a home theater.
 
Thanks a lot! I learned so much already the last few days, it's overwhelming.

I started the 'journey' with the JTR 212HTR as inspiration, now I'm contemplating coaxial silk domes 🙂 When in doubt, I always try to think of what I'm looking for in a system (sorry for the rambling, you can skip to the bold part)

I've owned my fair share of speakers, bought and sold a lot of them chasing the 'best' sound. For me a couple stood out:
  • Canton CT2000: great low end with the iconical Canton 12" woofer, really moved your chest and made a huge impact in movies. Didn't like the top end so much. (have it still in storage)
  • Infinity Rsb: loved the high end, low end bit muddy. My hairs started rising at high frequencies. (still have them in my attic)
  • Infinity Renaissance 90: loved them and to this day it pains me I sold them for way too cheap (500 eur for the pair) but I wanted to invest in a matching center which did not exist with the exact same mids and highs. This had the best midrange of all of the above and the Watson woofers really made an impact, though not as 'exciting' as the Canton, bit clinical, and they needed a lot of 'space' out of the wall to sound good, also very demanding on the amplifier. At higher levels they also felt a bit 'sharp', you could feel they struggled a bit.
  • Piega P5 ltd (current): love the planar mid and the ribbon tweeter, as good as the infinity, though less powerful, but the low end is a bit disappointing, though it measures really flat, you don't 'feel' it. Also in music, Michael Jackson for some reason sounds great on those mids and tweeters.

Looking back at my previous experience, I don't want to move on the low end, should be a 12" minimum. The mid and high, I don't like dome tweeters, I feel like they are too soft and 'slow'. I had a Piega center speaker with a dome tweeter, I exchanged it for the (much more expensive) center with a ribbon and it sounded much better. I don't know how to explain as I'm not an audiophile, I always come back to the rain example because that stands out with the Piega speakers, really feels like it's raining while with dome tweeters it sounds like it's raining (if you understand?)

So taking all this into account, I would like to take again a 'leap of faith' and sell my beloved Piega speakers to build a fully custom LCR with all the positives of my previous speakers. I want to avoid the trauma of the infinity renaissance 90 sale, this will always be my benchmark, but needs to be better 🙂

If you tell me know it's just not in line with what I'm looking for, better to stop the project now and go to a real 3 way with a super tweeter instead of wasting money on expensive drivers 🙂

So decided on 2x12", SB Audience 12MW200 is flat to 60Hz in winisd vented 150L tuned to 50Hz and below 100 euro a piece. Would use the MTM configuration, if I cross over at 700Hz according to the d'apollito design I need to be max 13520/700 = 19" center to center, which will be no issue with a 12", so that also fixes my desired crossover at max 700.

For the compression driver, I read through a complete topic (it was quite the read) on soundforum on the PM60, lots of good info, also some info on the crossover for the DCX354, which should be totally possible at 650Hz
https://soundforums.net/community/threads/60-degree-diy-mid-hi-aka-pm60.12390/page-52#post-217438
The horn they use is the RCF HF950 or the 18 sound XT1464/Ciara PR614. I think I'm kind of decided on the HF950 due to the wider dispersion and good loading down below. If there is a better horn, am I missing something? Doesn't look great on the higher freq? The PR614 and XT1461 have a totally different rounded design so not sure this yields benefits for hifi HT?

The biggest remaining open question to me is the type of compression driver. A coaxial or a (cheaper) CD with lots of low extension?? I want to crossover at 700Hz.

Actually, the ND950 has an FS of 350 so crossover at 700Hz should be no issue. It is also literally made for the RCF HF950 so very smart designers have matched these. The DCX354 can be crossed over at 650Hz (probably even lower if volume is not huge) and has about the same Fs as the ND950. The top frequency extension looks very similar between both as well. Only big difference (I see, I'm no expert) is the low extension which goes to a usable 300Hz on the DCX354 and 'only' 500Hz ons the ND950. Is this an issue, will i notice with a crossover at 700Hz?
Fs of the n314x is above 400Hz so they don't seem suited for a really low crossover.

Some graphs:

nd950 vs dcx354 freq response.JPG
dcx354 vs rcf nd950 impedance fs.JPG
n314x vs nd950 fs.JPG
n314x vs nd950.JPG
 
The biggest remaining open question to me is the type of compression driver. A coaxial or a (cheaper) CD with lots of low extension?? I want to crossover at 700Hz.

Actually, the ND950 has an FS of 350 so crossover at 700Hz should be no issue.
The ND950 on the RCF HF950 will be fine at a 700Hz crossover.
Covering 80-100m2 with a crossover of 700Hz the headroom available from the co-ax drivers won't be used unless you like levels well above THX standards, stuff like 12 gauge shotguns at "live" level in your home theater ;^).
Reducing crossover points for LCR will simplify your journey considerably.

Art
 
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Thanks a lot for the experts to chime in! @GM when you talk about a 2 way CD, do you mean a coaxial or as @weltersys advised using a CD in a 2way with a woofer?

I would be happy just to be able to decide on this, the more I read and learn about it, the more I realize it's often down to physics, no miracle CD driver exists, there is always some compromise to improve the efficiency or extend the low or the high end.

The B&C DE990TN also looks like a good candidate, used in the JTR 212HT (the 'lowest end' in the line up). It's within budget at 360 eur. Also a lot of other options pop up

Compression driver FaitalPRO HF1400, 8 ohm, 1.4 inch (toutlehautparleur.com)
Compression driver Radian 951PB, 8 ohm, 1.4 inch exit (toutlehautparleur.com)
18 Sound ND3SN compression driver, 8 ohm, 1.4 inch exit (toutlehautparleur.com)
Compression driver Radian 636PB, 8 ohm, 1.4 inch throat (toutlehautparleur.com)

The Radian claims to go to 22kHz (the only one I know which claims this). The faitalpro has a 'softer sounding' diaphragm (?) and so many other review stuff I've read...in the end I guess they all have their merits, but as I have a budget of about 4-500 euro for the CD (and for a coax this needs to include the passive crossover) I would like to spend once, cry once, but off course not overspend if not needed...

thanks a lot, welcome to the confusion 🙂
 
Not sure I got it all right. With LCR do you mean full range fronts or surround+center? Do you have subs in mind?

How about a 5x12’’ ribbon-coaxial as LCR (front+surround) mid/high and 2x12 Peerless XLS subs pr side for the lows? I would reconsider the 180cm height though no need for 150l to 80Hz.

https://radianaudio.com/collections...ts/12crf6430-12-coaxial-with-planar-ribbon-hf

Premade crossovers exists, so you don’t have to worry about that. Use DSP for taming/room tuning only.
 
Hi, thanks for the response. LCR a the left center and right, excluding rear surrounds (I have 5.1). I have 3 subs, 1 18" um 18-22 and 2 dual 15" lab 15 with 18" PR, each with a 1000+ W amplifier, so have the low end well covered, so going to crossover at 80Hz.

I looked at the AMT's, but didn't see those coaxials. Not a huge fan as the cone is kind of the waveguide for the hf, not sure how clean this will sound? Prefer a designed horn for that, though again I'm no expert, i completely go by what I've read and heared in other topics (and obviously, when I go to the cinema it's full of horns).

Got a tip to look at UK sites for faitalpro CD's, waiting for a final quote, but those prices look like halve of what I was used here
https://www.lean-business.co.uk/esh...114_220.html?zenid=8mdi591bdln512esnksa087a95

HF1440 would be only about 300 euro, which looks like a good price, though it's not an issue for me to spend 400+ euro a piece if the end result is better.

Looking at the faital series woofers, I actually think it's better to switch the woofers to faitalpro 12fe330, it's almost ruler flat to 2kHz compared to the sb audience, and still below 100 euro a piece so pretty cheap. I preferred the sealed graph on this one, goes nicely to 60Hz and with DSP easily to 50Hz in a smaller box of about 120L.
12FE300-8.gif
12fe330 sealed.JPG


(this is the max SPL graph, in red is the 12MW200, still it's more output, though the sealed faital will still be too much anyway for my room so totally fine with it, faital in blue. group delay etc will be better sealed but more power needed)

So looking at this, I think it's safe to take the advice of the experts and take a quality CD which covers 1kHz - 20kHz as flat as possible with as little distortion as possible. Would like to have a final decision on that to move forward so I can present the result to the budget approver, my dear wife.

For DSP I would just buy a 4x10 HD (2nd hand)

Thanks a lot!