JADS- NatP HT, or high efficiency on wall/in wall MTM for HT

[JonMarsh]

NOTE: This project is probably going to be converted to the Dayton SIG180-4 for the midwoofer- parts are on order as of May 29, expected by June 2 or 3.


Reason is smooth extended response and easier access in the USA. Choice is pending completing a measurement suite on the driver.

---

One of the things I realize is that in this new place, there is a potentially schizophrenic trend for audio needs-

On the one hand, there are going to be a lot of two channel audio "experiments" and systems going through cycles of test and evaluation, but on the other hand, for personal sanity and that of my wife, I think we need to have a relatively "stable" AV setup- that is, Audio-Video basically for disk movie watching and occasional streaming viewing.

And ideally, these systems shouldn't compete for space or electronics or whatever....

Steve had some discussions with an interested party who has been planning an upgrade to an upstairs space for quite some time, and though we don't have things to currently interest him, it did push my unconscious overnight (perhaps) and for what ever reasons I decided at lunchtime to review some of the pro sound drivers I've been interested in. Why pro sound? Well, there are mid bass/midrange parts that can offer some fairly optimized performance if you're not worried about what goes down below 80Hz, with a typical HT crossover setup. So, that got me thinking and perusing, and I found another driver from Faital that looks pretty interesting, either for MT or MTM applications. Especially on wall or in wall, where baffle step compensation goes away. How interesting? Let's consider some specs...

• Nominal diameter: 6"
• Impedance: 8 ohms
• Sensitivity: 93 dB @ 1M/2.83 VRMS
• AES Power handling: 200 W. (2 hours test according to AES 2-1984 Rev 2003)
• Xmax: 5.5 mm
• VC diameter: 1.75"
• Motor system: Neodymium ring magnet with demodulator ring.
• Le: 0.29 mH
• Fs: 65 Hz
• Frequency range: 80 - 6K
• Usable smooth flat range: 80 - 3K to 45 degrees

Yeah, probably sounds too good to be true. But my experience is that pro drivers rarely have over stated specifications.


OK, some teaser stuff....





This is only a 6" driver, and the HiFi folks would be calling it 5.5" as they do most of their 6" frame parts. The overall depth is 76mm, right at 3".




Of course, this stuff needs to be verified. At the moment, they're out of stock, but current info is back on stock in three days, so I ordered some to examine.


What might be possible, based on something more than back of the napkin calculations? This is at about 70% of rated Xmax for the highest excursion point in the enclosure setup I targeted, with 100W of power:





So, hitting reference HT levels is not an issue, it seems, with a bit of power. And that's per driver. As in an MT.


What kind of configuration would I imagine these in?


For an MT, seems like combining with a BlieSMa T25A or T25B with my LR3 style crossover around 2500 should work OK. Just like the early Modula MT and NatP.

For an MTM, we need a bit more sensitivity for the tweeters, and CTC is more of an issue, and I have a pair of BlieSMa T34B-4 with 97 dB/2.83 VRMS that ought to work fine, most likely with a crossover point of 1500Hz- remember, if on wall or in wall, no baffle step, so the effective woofer sensitivity is the same as the factory spec. Two of these mid woofers in parallel should hit about 95-96 dB for 2.83VRMS. Even a moderate HT receiver like the one Steve M gave me should push them more than hard enough. And I just happen to have a pair of those tweeters NIB on the shelf.

So, in a homage to history, perhaps these should be called the NatP HT if it all works out? They'll use the same crossover design, but at about 1500Hz, and without the baffle step correction.

Might be pretty interesting. I have an esthetic design concept in mind, but strangely, when I google wall mount speakers, nothing looks like it. And it all looks pretty ugly.

Oh, and while these are not bargain basement drivers, in comparison to Purifi, they are down right "econom" as my wife should say- about $130 each.


I'm very curious to get these in and do some basic measurements in a simple cabinet...


Oh, and JADS stands for "Just Another Design Study".


:rofl:

[1Michael]

I look forward to how this plays out!

[kravi4ka]

Most seriously interested as well… I was just wondering if I will have to build 11 or more of the Purifi SPK8 mini wonders… they are small and could be used as a center channel as well, tiny little monsters…

https://m.facebook.com/story.php?story_fbid=pfbid0AnfKSooGcAcm2ZY7k87ieWBT78fhYvutL2dDB8KXswV9Bns1qW8MxFmNJVWRPMJXl&id=1441833684&m_entstream_source=timeline&__tn__=%2As%2AsH-R

Now Jon comes with a kidney saving plan

What about this driver?

https://en.toutlehautparleur.com/coaxial-speaker-b-c-speakers-6hcx51-8-8-ohm-6-5-inch.html

[JonMarsh]

What about this driver?

https://en.toutlehautparleur.com/coa...-6-5-inch.html

OK, some random comments about my choice and in comparison to a standard PuriFi solution or the B&C 6HCX51. A lot of thought and "screening" went into selecting the Faital 6RS140.

• I think the PuriFi "mini speakers" as you call them are a very good compact general purpose solution for two channel music, espcially when you can cough up some extra watts to power them. I have some of the new aluminum ones, too, and I have ideas for a smallish music speaker with them, too, but with Wavecor PR's and BlieSMa T25 tweeters- those are on hand, too. But... sensitivity is not their forte... there is a lot of focus (and money spent) on LF extension, which for this HT application isn't needed considering a typcial 80Hz high pass crossover. 5-6 dB more sensitivity is a big deal, when it comes to HT amplification.
• My guiding concept for this project is spend the money on the things that are needed, and when possible, choose so that one doesn't have to spend too much money- say, on crossover parts- to compensate for issues with the drivers!
• The B&C 6HCS51 seems to be a combination of characteristics I've seen in pro midwoofers or midrange before- that is, a rather high sensitivity above 250 to 300Hz, (which usually correlates with the impedance minima) but T/S parameters that put the 100Hz and below sensitivity quite a bit lower.
• Specifically, for the 6HCX51, which is also available at PE, the nominal Fs is about 90 Hz, not 65 like the Faital 6RS140. Lower compliance is the main reason, becuase the Mms is essentilaly identical.
• Then, the motor seems to be relatively "old school" in spite of being a Neodyumium magnet assembly- seems to lack a demodulation ring, which is revealed by the much higher Le and rising impedance, which will contribute to inductivity modulation distortion.
• Now, I like the idea of coaxials, whether tweeter or compression driver, but the HF part has to be well designed, and fitting it with a woofer in the same chasis makes that job hard. My reference for low buck polyester compression drivers is the SB Audience series, particularly the Bianco-34CD-PK, which is very well designed, has a surprisingly smooth impedance curve (which is only surprising because of the price point of ~$60- given the smoothness of frequency response, it would have to be that way); and for higher performance in 1" CD, the Eighteen Sound parts like the NSD-1095.
• First thing to check always is the impedance curve... mmm, not so nice. Could be diaphragm design, but most likely its the slot pattern and feedthrough. That's going to be a tough one to do a nice crossover for- given how it looks directly driven from a voltage source- think muliple Zobel LRC shunts, and even so, I don't see how one can justify calling the HF range anything better than 4kHz to 20kHz.
• Oh, and that also brings up the woofer- Geez, folks, that's a nasty spike at 2 kHz; describing it's range as extending to the peak of the first breakup mode is more than poetic license- it's pure chicanery.
• And for the privelge of these fine characteristics, the price at PE is about $100 higher than the 6RS140. Of course, it includes a tweeter, but one that I would basically want to throw away.
• The B&C 6MDN44 would come closer to the target requirments, minus the coax tweeter, but really is just a midrange driver, with an Fs of 140Hz, and a highish inductance and rising response to 5kHz before breakup and collapse. The B&C 6MBX44 Neo "Woofer" exhibits some of the same characteristics, with an Fs of about 115Hz, impedance minima at 500Hz which is where the response flattens out up to about 1400Hz, and a primary breakup mode and peak at 4kHz (how do they justify calling this driver range 115Hz to 5kHz when that fits within a 17 dB range?)
• The 6RS140 has almost text book characteristics for what I'd want for this application, including very smooth extended response without a clear breakup peak (reminds me of the PuriFi Midrange), a low inductance hinting at controlled inductivity modulation, and an Fs and sensitivity in a very desirable range for HT.
• And the BliSMa tweeters hardly bear commenting on- some of my favorites, for their significant design break throughs.

That about sums up my thoughts.

Oh, the only other "recent" things were my musings in bed at about 3 AM today; given how shallow I'd like to make the enclosure design, I'm seriously considering making the enclosures primarily out of phenolic panels usually used for fixture tooling. My favorite crossover board material is the 1/4" stuff, but I've also got Leecraft panels in 3/8" and 1/2" that might be very interesting for this project. There's no comparing the strength against MDF...

[dar47]

Nice! Jon

Ben is in on these he is just starting a basement home theater, Me being greedy i will wait for the 7" Purify with the BlieSMa beryllium tweets for my living room, lol.

[JonMarsh]

Nice! Jon

Ben is in on these he is just starting a basement home theater, Me being greedy i will wait for the 7" Purify with the BlieSMa beryllium tweets for my living room, lol.

Sounds like a good plan to me!

I'm kind of excited about the luck I had finding these drivers and think I have some good ideas for how to implement once I've verified the woofers. Of course, inputs and ideas are welcome. What I have in a nascent conceptual form is something like an AR LST with facets on four sides, probably the top and bottom ones with grille cloth to provide a port flow path, and the sides just solid wood to make a smooth baffle path to the wall.




And shallower- shooting for no more than 6" deep.


I could imagine MT's for rears to be similar, but smaller, and at ear level seated. Of course, one could push them up to the ceiling and only have down tilted tweeter, but I think that would mess up the response.


I'm thinking the core enclosure could be phenolic, and the wings solid wood of whatever type is convenient or desired, and not part of the acoustic enclosure. Say, wood wings on the sides, and grille cloth facets top and bottom for port exits.

But that is getting a bit ahead of things - need to test drivers first. Have a lot of stuff lined up for that, have been building test enclosures for several items entering POC phase.

[benthe8track]

Hey Jon, these look like a great fit for my theater project.

Still early days for this project but I have a a sketch, 4 Stereo Integrity subs and a pair of pro audio amps.


Could something similar work for Atmos height channels as well?

I bet phenolic cuts really nicely on a water jet. Humm..

[JonMarsh]

Hey, Ben!

The MT concept for this should work fine for an ATMOS height channel or a normal surround channel. I say that based on the official Dolby theater specs for ATMOS speaker systems- (which I have) of course, much of what is sold into the home market won't meet those requirements, and fuggetabout the whole bounce it off the ceiling stuff (nonsense in my opinion, because of lateral bleed and likely timing issues). So when someone says they have Dolby ATMOS incorporated into a sound bar, the most I can conclude is that they put a channel in their and paid the licensing fee. Not much more.


Now, normally ATMOS individual speakers should function like regular surround, which according to Dolby means that each speaker must be capable of generating 99 dB continuous SPL at the reference listening position, and preferably with an amplifier with 3dB of headroom over that. The surround frequency response for the system should be 40Hz to 16kHz, +/- 3dB. Obviously, most surround speakers require bass management support, but the surround speaker response should extend to 90Hz or lower, and the crossover frequency should not be higher than 100Hz. (I'm essentially direct quoting).

The surround array SPL level capability requirement is 105 dB continuous in aggregate, which for arrays less than 4 speakers each speaker must be able to do 99dB continuous SPL at the listening position. Small room, and the requirements are not too demanding.

Now, note, the proposed Faital 6RS140 mid woofer has an AES power rating of 200W for two hours within it's recommended bandwidth, and in the configuration shown with 100W of power it's very close to 110 dB at 1 meter. At two meters that will fall by 6 dB to 104 dB, and at 4 meters (25 ft) it will fall another 6 dB, to 98 dB. So, I think it's reasonable to say that in a large home environment it can meet the letter of the Dolby ATMOS requirement for surround speakers.

Now, for my next question, I should turn things over to ET, right? Which is, how many home Dolby ATMOS setups have a speaker that is that efficient (92-93 dB) or will play that loud, and how many home receivers have 100W per channel with 3 dB headroom (which is 200W!) for the surround and ATMOS channels?


Ahem. I'm waiting.... ummm, where is that list?

Oh, how about this Rotel RAP-1580MKII, 7.2 ch AV receiver... 125 watts per channel into 8 ohms, with 2 channels driven (oh, you want more simultaneously operating channels from your 7.2 channel receiver that goes for $5,499? Don't you think you're being a bit unreasonable?)

Ah well, they have you covered, full 11.2 channel RCA outputs for external amplifiers. RCA? Ewwww!


Sorry, I'm a pro audio snob. Since way, way back. '70s to be exact.


Actually, the Anthem MRX1140 might be a better bet, 5 analog channels and 6 Class D channels, but the latter are rated at just 60W, and it's got RCA line level outputs too.

And let's not even discuss the distortion specs for these guys. It's like setting the way back machine for 1980.


OK, I'll go back into my corner, but I'm not going to sulk, maybe just chuckle a little...

[Jonasz]

Here is the Audioxpress test of the Faital https://audioxpress.com/article/test...oofer-midrange

[JonMarsh]

Thanks for the review link! The info is encouraging- the Kippel data looks very clean, and as the performance envelope in Unibox above is under 4mm Xmax, I’d say it looks like we’re on the right track. In normal fairly loud usage in a home environment, Xmax should be under 2mm. A series notch filter at 6kHz should help with the distortion plots- we’ll just have to see how much.

They should be back in stock today and shipping soon…

















I'm very interested to see how the performance works out in the planned configuration. The results from AudioXpress seem encouraging for this half space application using my normal crossover techniques.



And for anyone reading this, don't forget this evening HTG will go off the air for the weekend for the big software update!

[JonMarsh]

Here's an interesting link with detailed about Troels Graveson build in 2019 using the 6RS140...

http://www.troelsgravesen.dk/Faital-3WC.htm

I'm going to include a few quotes from this article...

Going through the 5-6" drivers from Faital, my eyes fell on the 6RS140 and it looked like an interesting midrange driver with a quite smooth frequency response - and I bought a pair.

This is the second time I've used a PA midrange driver - and like the 18 Sound 10NMBA520 used in the The Loudspeaker, this 6" Faital 6Rs140 surprises me, it surprises me a lot! Given its 93 dB sensitivity and smooth frequency response it has a dramatic impact on the final performance of this speaker. Good bass drivers we can get from a lot of manufacturers, although the 12" range is limited for domestic use due to high Fs, but from 15" and 18" drivers there are multiple choices. And really good tweeters are in abundance these days. The 6RS140 has excellent dispersion, which creates a strong presence, yet smooth on the ear due to low distortion. Should you fancy percussion, look no further, this speaker has it. Rimshots are a delight, fast as lightning and with that ultra short decay only high-efficiency speakers can manage.

And while I'm not a fan of Troel's measurement techniques or setup, it's probably still worth sharing the measurement of 4 6RS140 on his test cabinet:





Just for the record, I only discovered this post late yesterday evening- I hadn't stumbled across mention of the 6RS140 previously, but I'd say this is a fair endorsement of it's sound quality and utility.

[JonMarsh]

A small update and a teaser of sorts...


First, the back in stock date from Parts Express for the 6RS140 has slipped back out to the originally quoted August 12. In this day and age, that shouldn't be too surprising.

After reviewing the concept with Steve, he has opined that if I can come up with a design interesting to folks, he thinks he could generate flat pack kits if there is interest for in wall or wall mount versions. As I'm very seriously looking at phenolic enclosure construction, this could be fairly handy for those that aren't handy.

Additionally, though I don't have test data on the 6RS140 yet, I do have early test results of one of it's baby brothers (or sisters!), the 5FE120, which is being considered for a new compact CC design in a standalone enclosure, as the midrange element. It too, has fairly high sensitivity for an 8 ohm driver, at about 90 dB for 2.83VRMS.






This test was conducted with just 2VRMS, and at about 24", so no conclusions about sensitivity, but it's in the ball park of what you'd expect. What I was mainly concerned with is looking at the frequency response on and off axis and doing a basic check on distortion, for the CC application in the range of 400Hz to 2500Hz. The data sheet looks very good, but reality sometimes misses the mark.



Here's on axis:





And for contrast, here's 45 degrees off axis:






Distortion was in the -50 to -55 dB in the range of interest, so this is promising for the CC application, and promising for what we can expect from the 6RS140. A few more BlieSMa tweeters hit the dock from Solen this week, too... so a bit of progress all around!

Now, if only PE would ship!

[kravi4ka]

Flat pack kits is music to my ears…

I have been very tempted by this one but could not sell the house at the right price to be able to afford the whole set for a HT…


https://audioxpress.com/news/ggntkt-...n-and-dynamics

[JonMarsh]

Pretty cool article you linked to!

[kravi4ka]

GGNTKT has some really appealing ideas and WAF is very high, especially for the HT speakers.
Audioxpress is quite fun sometimes, today I read this, off topic but really makes me want to buy 26 large sheets of Wisa plywood:

https://audioxpress.com/article/patent-review-inverse-horn-loudspeakers

We are all here because we can’t stop, right?

[JonMarsh]

GGNTKT has some really appealing ideas and WAF is very high, especially for the HT speakers.
Audioxpress is quite fun sometimes, today I read this, off topic but really makes me want to buy 26 large sheets of Wisa plywood:

https://audioxpress.com/article/patent-review-inverse-horn-loudspeakers

We are all here because we can’t stop, right?

Most definitely! Guilty as charged!!

Now, with PuriFi or the new Hypex modules, we could attempt something that matches the full performance characteristics, but for now I'm in favor of a simpler solution attractive to the budgets of more members- as well as myself!

[JonMarsh]

An open box 6RS140 just popped up at PE, so I ordered it, should be here by Monday. I may be on vacation nominally, but I'm still working the issues!

This will be the primary test article and for first MT prototype.

[theSven]

GGNTKT has some really appealing ideas and WAF is very high, especially for the HT speakers.
Audioxpress is quite fun sometimes, today I read this, off topic but really makes me want to buy 26 large sheets of Wisa plywood:

https://audioxpress.com/article/patent-review-inverse-horn-loudspeakers

We are all here because we can’t stop, right?

Yes that is how it started out for me, and the adventure continues!

[JonMarsh]

OK, UPS was a bit "late" today, but actually early overall on this delivery which was originally scheduled for Monday! This is the open box sample I was able to order. Looking good, in my opinion, but then I'm always a sucker for cool looking hardware...






Once I get the Dual ES180TiA test box assembled, getting a test enclosure for the 6RS140 is high up on my to-do list- mainly I just need to cut a front panel and install ports, the basic box is ready.

[JonMarsh]

Slow work takes time... Have successfully purchased 6RS140 from Europe, and today (Saturday, 9-10) loaded up large phenolic sheets to bring out of storage. Also stocked up on more BlieSMa tweeters, and note that Solen's stock situation is improving.

With the dollar as strong as it is right now, buying from European vendors can make a lot of sense, especially for European built parts. Also looking at some other Faital woofers available in Europe.

Can build a first test box pretty soon, moving some wood working stuff temporarily to the back patio, for various reasons.

[JonMarsh]

Flat pack kits is music to my ears…

I have been very tempted by this one but could not sell the house at the right price to be able to afford the whole set for a HT…

Today's update addresses the whole cost thing, with some ideas being explored for a level of performance close to what I've proposed for this concept, but at a more pocket book friendly price. This doesn't mean the 6RS140 concept with BliSMa tweeter is being dropped, but more that it will have a little brother or sister.

One of the things I liked about the 6RS140 was the depth- critical to either version of this application. Well, there have been a lot of distractions the last few months, but then reviewing my driver stock, I had a small "Ah hah!".




Remember this "little guy"? The Eighteen Sound 6ND430? One of the first drivers I know of to experiment with an engineered surround to reduce spurious outputs in the midrange?



Well, gaze on the mechanical details...





It's hard to find a driver in this size class this shallow, and it actually beats out the 6RS140 by a few mm. Like the 6RS140, it has a powerful Neo motor, a low inductance design, and high power handling (2 hours pink noise, 200W).

The cone design is what I now call "classic Pro Audio Paper cone", which PuriFi seems to follow fairly closely for their papers cone drivers, and is visually nearly identical to the 6RS140. The main reason for this is the very stiff behavior and low breakup mode Q.

Of course, Steve won't like routing a rebate for it anymore than the 6RS140, but for a home constructer, it would be simple to construct a routing guide as I did for the Accuton C79.

My own measurements show good off axis performance, too. This is mounted in a small, narrow enclosure, not on a flat baffle.






OK, this is all well and good, but what about the Tweeter? I love the BlieSMa on paper, but even the T25A-6 can't really be called a budget tweeter...


I have a possible solution, but there are details to check and logistics to work out.







8 pieces of this part by a well known manufacturer are on the way to me, from Europe. The supply is limited, but not small. I hate the new abnormal with all of it's supply chain issues.


The factory curves look like this:




We've had very good results with another related part from this manufacturer, but they have become "unobtanium", apart from the 6 pieces I have on hand. Testing and consistency checks are in order next.


BTW, PE pushed out delivery dates for the 6RS140 again, until mid October. I have five on hand, three sourced from Europe. I'm looking at the 16 ohm version for the possible on wall/in wall MTM.

[Steve Manning]

Ah, but unlike the drawing for the 6RS140, this one provides a diameter for the curves .... makes life so much easier! 😊

[Evil Twin]

An interesting concept, of course I would be most curious to see how the step response appears for what at first examination appears to be a multi-resonant system.

But, practical or not, no reason not to indulge yourself.

I find that given the projects in the queue, I have a surprising accumulation of wood and synthetic panel products in this remote location... some arriving just a few days ago to support new requirements from the Chancellor!

[kravi4ka]

(Cough cough)

[JonMarsh]

(Cough cough)

🤣

One of the challenges I clearly have underestimated is all the mundane tasks my wife can come up with for me to do for HER pet projects... this last week has been a text book case!

So, I've definitely over estimated the amount of time that would be available for MY projects... like this one.

But this is an "interesting" coincidence, as ET might comment, in that today I'm planning some more measurements using my newer Fuzzmeasure setup on the 6RS140 test cabinet prior to setting it up for some PuriFi woofer tests for a two way project with several POC concepts under consideration. And I'm running impedance sweep checks in the DA25BG08-06 this morning- I've been setting up tweeter test baffles for a number of parts, including the T25A-6 and the TPL-075.

I think I foolishly thought I could put time into these projects the same way I used to put time into my day job...

BTW, Z curve looks pretty nice, Fs about 650Hz, broad enough that an LCR Fs zobel will likely be desirable. Fairly flat between 2K and 20K.

[joecarrow]

Hi Jon, it's been years since I dropped in and I was delighted to see that you're still at it here! I built the Modula back around 2008 or so, and since then I've built some more things and moved on to designs of my own. I'm seeing a lot of overlap between my latest interest and what you're looking at in this thread.

I started out using the RS225 along with a dome tweeter in a 3D printed waveguide and wasn't crazy about how that was going for me, and so I tried the Faital 6F100E and liked that even less. Not long after that I got really excited about the Peerless HDS-830869, which seem to have been discontinued. I saw what you're up to here and I wanted to ask, what do you think of these?

SB Audience Rosso-6MW150D 6" Paper Cone Pro Midbass 8 ohm (madisoundspeakerstore.com)

[JonMarsh]

I have several of the Rosso series drivers on hand; the W150D is targeted at high efficiency midrange line arrays- for this application, the problem is that we should like to see fairly flat response down to 80 Hz or less.. The 6MW150D has a lot of drop off from 300-400 Hz down to 100Hz, about 8dB. What we really want is a driver that is close to flat on an infinite baffle down to 60-80Hz.

[JonMarsh]

NOTE: This project is probably going to be converted to the Dayton SIG180-4 for the midwoofer- parts are on order as of May 29, expected by June 2 or 3.


Reason is smooth extended response and easier access in the USA, good efficiency (about 91 dB) and very smooth top end. Choice is pending completing a measurement suite on the driver.