Adding sub to (my) "Belle's"

[ClaudeJ1]

7 hours ago, Chris A said:

Most people's setups that I've witnessed cannot give up even 1 dB of deep bass gain due to the nature of the problem, namely the narrowing equal loudness contours below 100 Hz, as seen in the following equal loudness contour plot.  Small changes in measured SPL lead to disproportionate changes in perceived bass loudness (which is particularly evident when demastering stereo music tracks for bass output in rooms that haven't been calibrated with each other carefully):

First of all I certainly agree with your sentiments here, Chris, but I do NOT have most people's setups, far from it. Second of all, my Xover point to the subs is 40 Hz., NOT 80 Hz like most people. I assure you that I can give up way more than 1 db (probably more like 20 db) of deep bass to get things flatter and better distributed BEFORE I apply EQ. All 6 of my surround channels can reach 130 peaks EASILY...............BUT, I typically listen to 85 db typical and 90 db Max. unless I'm trying to impress someone with a demo......usually real live SPL on a guy beating the heck out of drums (Chesky recording) or the sound of a rotary engine on an airplane (courtesy of Don "DB" Keele). In those cases, 120 db happens for a short time. Also the plane  crash scene in "Rise of the Phoenix" is a good one. I am VERY happy with my setup, but I just want to try 4 subs for the heck of it instead or just reading about it......putting my money where the theory is, so to speak.

 

My upstairs loft is 18" wide x 29.5 feet long with a 7 ft concrete ceiling. The rear TH sub (with a killer MTX driver in a tapped horn) is in a half high wall to an opening in the stairway, about 3.5" in from the 29.5 dimension, so about 26 feet away from the front sub, which is an OThorn with a 24" B&C driver that can handle 4 Kilowatts easily. This second floor loft sits above a main floor which is 45' x 18" with a 14' ceiling. My 18' wide front wall is also only half high, so it's really a very "open" room. So it would appear that super long wavelengths have plenty of space for non-linear propagation!

 

The front and rear, 4 ohms subs are powered by a FANLESS Crown K2 that can do 1 KW peak per channel into those subs, which are 97-100 db efficiency for a 1 Watt input. I can easily reach 130 peak levels with just those two subs. Those who have heard and FELT it with just the two described here have said it's the most defined, deepest, and tightest bass they have ever heard on any program material.

 

Now imagine soon adding 2 more, which are about 106 db/watt, being Full Horns on each side (shorter distance apart), with another K2 amplifier (same 30 db Watt peaks PER horn as the existing ones). Most people that test a SINGLE THT with a 20 Hz. sine wave generator say their windows almost blow out from the 120 db SPL@ 1 meter with only about 10 volts (25 Watts). I believe strongly that HEADROOM is alway your friend in Audio!!

 

Hopefully, the OP will consider Tapped Horn or Full Horn subs in his setup in order to better integrate with super efficient BELLES!!

[ClaudeJ1]

12 hours ago, Chris A said:

I've not seen these facts.  It would be instructive to see them so that I don't make the mistake again of being in error on this particular subject.  Could you post the links here so that I could be enlightened?

 

Most people's setups that I've witnessed cannot give up even 1 dB of deep bass gain due to the nature of the problem, namely the narrowing equal loudness contours below 100 Hz, as seen in the following equal loudness contour plot.  Small changes in measured SPL lead to disproportionate changes in perceived bass loudness (which is particularly evident when demastering stereo music tracks for bass output in rooms that haven't been calibrated with each other carefully):

 

 

I find that all sound reproduction setups are limited by low bass reproduction SPL and nonlinear distortion (particularly amplitude modulation [AM] and harmonic distortion).  Requiring 10 dB more output from the subs results in really big changes in perceived loudness and in the cleanness of the presentation--in my experience.  Horn loading gives margin, but subtracting 10 dB of gain is like giving up 2/3s of of the gain advantage of using horn-loaded subs in the first place (amplitude) and even more in terms of nonlinear distortion.

 

Chris

BTW, your "demastering" of studio recordings is basically removing the "radio rolloff" that producers insisted upon before the loudness wars, which things are twice as messed up as they ever were...........except jazz recordings from the late fifties/early sixties, but even then, they were mixed for vinyl, which required bass from 250 down to be mono, so both speakers shared the load..........just sayin. Also, the Fletcher Munson curves and their "updates" were based on headphone listening and NOT loudspeakers in rooms, which, to me would yield radically different curves. But I'm sure you have different thoughts on that.

[jason str]

20 hours ago, Chris A said:

I don't believe that figure shows what I thought you were implying above: that DR and TH subs do not experience this effect in the same way as conventional FLHs.  Perhaps I missed what you imply with this figure. 

 

In my experience, TH subs actually tend to respond more strongly to mutual coupling than conventional FLH subs due to their (typically) exaggeratedly small mouths--relatively speaking--and the relative gain in mouth loading due to having another TH sub mouth close by (within 1/4 wavelength).  A TH sub is typically looking for more effective mouth loading than conventional FLHs and therefore respond more strongly when it finds something that provides increased resistance--like a larger horn mouth, but in this case two or more coupled TH mouths.

 

A DR sub seems to gain more from mutual coupling to room boundaries and is looking for a room boundary (or another subwoofer diapragm or horn mouth) to increase loading to the DR driver diaphragm at low frequencies, thus increasing the real part of impedance to the coupled air mass. 

 

All three types (FLH, TH, DR subs) experience what the figure above shows: a lowering of the low frequency roll-off point and increased overall gain due to mutual coupling.

 

Chris

 

I have just heard different from a few sources, Bill Fitzmaurice has stated a few times what i said previously, one of Danley's guys mentioned it here as well as one of the local builders here.

 

I can see the V plate technique working with tapped horns but having a hard time seeing anything more than the normal increase of dB from additional cabinets with DR's.

[Datcc*]

I have a mac 6450, Klipsch Belles, and Heresys.  Just added the Klipsch 12 in sub...Thanks Santa!  Sounds phenomenal with the horns!

[avguytx]

@Datcc* Thanks for the input.  As you can see, this basic topic I started took off into all sorts of deliberations.    Good to hear your sub worked out.  Which one did you go with?  What size room do you have your LS's & sub in and where did you locate yours in relation to the LS's?

[ClaudeJ1]

On 12/20/2017 at 12:14 PM, Chris A said:

I've not seen these facts.  It would be instructive to see them so that I don't make the mistake again of being in error on this particular subject.  Could you post the links here so that I could be enlightened?

 

Most people's setups that I've witnessed cannot give up even 1 dB of deep bass gain due to the nature of the problem, namely the narrowing equal loudness contours below 100 Hz, as seen in the following equal loudness contour plot.  Small changes in measured SPL lead to disproportionate changes in perceived bass loudness (which is particularly evident when demastering stereo music tracks for bass output in rooms that haven't been calibrated with each other carefully):

 

 

I find that all sound reproduction setups are limited by low bass reproduction SPL and nonlinear distortion (particularly amplitude modulation [AM] and harmonic distortion).  Requiring 10 dB more output from the subs results in really big changes in perceived loudness and in the cleanness of the presentation--in my experience.  Horn loading gives margin, but subtracting 10 dB of gain is like giving up 2/3s of of the gain advantage of using horn-loaded subs in the first place (amplitude) and even more in terms of nonlinear distortion.

 

Chris

Since horn subs have, generally, a 10+ db advantage over sealed or Bass Reflex, it's the one that can afford center wall placement the most for the smoothest rendering of super low frequencies in any given room. I am not a "true believer" of the Fletcher Munson curves and the even more radical ISO version, adapted in the new millennium. Those were done for HEADPHONES and not loudspeakers.

[Thaddeus Smith]

On 12/19/2017 at 9:05 AM, Chris A said:

My two corner-located (DIY) TH-SPUDs have precursor pulses from the mouth side of the tapped horn woofers...that Audyssey likes to key on for setting time delays.  I simply add 21 feet (about 18.6 ms) to that distance manually, corresponding to the path length of the TH-SPUD horn in order to get the subs in time alignment with the other surrounding loudspeaker channels. 

 

 

I'm going to assume you're using Audyssey Pro here? I tried to do this last night and my implementation of Audyssey XT32 with SubEQ kept bitching at me with an error that the distance between my closest speaker (~5ft surround left) and furthest speaker cannot be greater than 20ft. So tacking 21ft onto the existing measured distance of 20.1ft (physical actual is about 15ft) is an absolute no-go with this AVR.

[Chris A]

It turns out that 40 Hz has 28.3' wavelengths at room temp, so 20 feet of time delay offset (the most that my AVP does, too) is well below 1/4 wavelength--so "good enough for gov't work" applies.

 

Chris

[Thaddeus Smith]

Thanks!

[uams]

Is there a recommended high-pass crossover frequency for the Belle's when integrating them with subs?

 

I've read about the folded bass horn of the Belle and how it supposedly stops acting like a horn below some 100Hz(?) or a bit higher, please correct me if I'm wrong here, and therefore I'm thinking the ideal high-pass frequency would be where this occurs (i.e.: where the folded bass horn stops acting like a horn). Of course this needs for the subs to cleanly reproduce at +100Hz. 

 

My main speakers are inspired by the Belle, and the folded bass horn is similar (while the rest is not). I have a pair of tapped horn subs being build as we speak, lilmike's MicroWrecker's, and so am very interested in learning about the above. Initially I planned to run my main speakers full-range with the MW's (crossed about 60-62Hz), but I've got hold of an excellent digital XO, a Xilica XP-3060, that I would like to try inserting over my main speakers (with their passive XO's still in the chain), and experiment with high-passing them. I intend to start with a 100Hz high-pass to the MW's.

[Chris A]

Yes.  If you've got the Belles located mid-wall away from the corners, I'd cross over at 80 Hz, or perhaps even 100 Hz.  Here's a natural response of an 1981 Belle without corrective equalization, located in the center position mid-wall between my left-right Jubs.  You can EQ the midbass on the Belles down a bit based on what you see here:

 

 

Chris

[Chris A]

Here's a thread on tri-amping a Belle using a DSP crossover (EV DX38), including the settings that I used.  These settings will also work quite well using a Xilica XP series crossover if you convert filter "Q" to bandwidth.  There is a conversion scale at Rane's site:

 

 

Chris

[uams]

Thanks, @Chris A - will get back to you shortly. 

[Chris A]

By the way, the free Xilica XConsole control software available for download on the web also converts your input bandwidth settings into a filter "Q" and displays it just below the bandwidth input value, so you don't need the handy Rane conversion scale.  You can simply iterate the bandwidth settings until the resulting "Q" that is calculated and displayed is the value that you desire.

 

Chris

[uams]

Sorry for the late follow-up. 

 

The two MicroWrecker tapped horns of "lilmike" (over at the Avsforum) have now been implemented, though only for about a week and a half. Those B&C 15TBX100 drivers are still very stiff (forgot to run them in before mounting them) leading to a somewhat lean and slightly lack-of-impact bass, and optimization still has a long way to go, but overall I'm impressed by their imprinting.

 

As of now am toying with delay and crossover between the MW's and mains via the Xilica XP-3060 and the XConsole control software, presently sitting at 90Hz x-over with 48dB/octave slope, Linkwitz-Riley. I'm also running a HPF at 20Hz 48dB/octave Butterworth, mostly as a means of theoretical diminishment of distortion. I've yet to start PEQ, but later will try a REW-treatment (maybe also DRC Design) to see how that fares. 

[MEH Synergy]

5 minutes ago, uams said:

Sorry for the late follow-up. 

 

The two MicroWrecker tapped horns of "lilmike" (over at the Avsforum) have now been implemented, though only for about a week and a half. Those B&C 15TBX100 drivers are still very stiff (forgot to run them in before mounting them) leading to a somewhat lean and slightly lack-of-impact bass, and optimization still has a long way to go, but overall I'm impressed by their imprinting.

 

As of now am toying with delay and crossover between the MW's and mains via the Xilica XP-3060 and the XConsole control software, presently sitting at 90Hz x-over with 48dB/octave slope, Linkwitz-Riley. I'm also running a HPF at 20Hz 48dB/octave Butterworth, mostly as a means of theoretical diminishment of distortion. I've yet to start PEQ, but later will try a REW-treatment (maybe also DRC Design) to see how that fares. 

Very intersting looking Belles.   I quite like that look. 

[uams]

Just now, Westcoastdrums said:

Very intersting looking Belles.   I quite like that look. 

 

Thanks, they're actually Simon Mears Audio Uccello's, inspired by the Belle  

[MEH Synergy]

Just now, uams said:

 

Thanks, they're actually Simon Mears Audio Uccello's, inspired by the Belle  

Well that explains that. 

[uams]

On ‎2‎/‎1‎/‎2019 at 12:12 AM, Westcoastdrums said:

Well that explains that. 

 

The closing statement of Kevin Fisk's 2014 review of the Uccello's might be worth stressing:
 

Quote

 

… They are indeed an homage to Paul Klipsch and the Belle, but they are not a backwards look. They are history jump-started and brought bang up to date.
 

Not in a million years would Simon Mears say this of his own work, but I can: I think that Paul Klipsch and the horn pioneers would approve.

 

 

http://simonmearsaudio.com/uccello-review.html

 

An homage and development, not a ripoff - if it makes any difference among the diehard Klipsch Heritage fans here  

[Marvel]

On 12/21/2017 at 12:50 AM, ClaudeJ1 said:

but even then, they were mixed for vinyl, which required bass from 250 down to be mono, so both speakers shared the load..........just sayin.

 

I believe it wasn't so both speakers shared the load, more so the stylus would stay in the groove as it moved to mono when the frequency dropped.

 

Bruce