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Multi-Way Conventional loudspeakers with crossovers

Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
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Old 28th August 2019, 02:42 PM   #2401
phase_accurate is offline phase_accurate
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Every sub I’ve modeled has higher excursion as sealed vs ported. The Td15m, ported, has the lowest excursion within the subbass of all AE subs I’ve modeled. Group delay is on par with The Td15h (ported)...else wise, all sealed subs obviously have way better group delay. What you say about that?
When you compare subs with two-way speakers then you are definitely doing an apple to oranges comparison. With a two-way it is definitley advisible to use bass-reflex in order to keep excursion low because of IMD and FMD. These two distortion types are less important with a pure sub that doesn't have to reproduce midrange frequencies. So it is either a two way with bass-reflex or a three way where the low-mid and sub are built as closed-box in order to keep group-delay distortion low.

Regards

Charles
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Old 28th August 2019, 03:23 PM   #2402
Ro808 is offline Ro808  Netherlands
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These drivers and horns are 'save bets' tuyen. I am sure you'll like 'em even more, once you've optimized the system.
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Old 28th August 2019, 05:16 PM   #2403
Ro808 is offline Ro808  Netherlands
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So let's take a closer look at Vance Dickason's far field monitor project.
Especially the woofer is a rather particular choice.
If you like energy storage, this is your driver!

Due to an ultra heavy cone (Mms: 240g !!!), sloppy NBR surround and subsequently a high compliance double spider, this driver needs a powerful motor structure.
It's a B&C, there are no doubts about the engineering of this "ScanSpeak HiFi woofer on steroids".
This driver is the opposite of what I consider sensible.
Because of this, it probably makes sense (again).

I couldn't find additional info on this far field project, so we'll have to guess.
One obvious clue is the designer, David Nelson of Triad loudspeakers.
If you check his website you'll find he's a proponent of sealed box designs.
In fact, I couldn't find any bas reflex design.

With this in mind and considering the B&C's 'physics', it's not surprising this driver is probably one of the best B&C 15" woofers for use in a SEALED cabinet.

IMO you'll have to be a closed box fetishist to use this driver and not really care about the midrange (where most of the music is).
Here's the paradox:
If you look at the response, the huge breakup spike at 1200Hz stands out.
Personally I wouldn't use this driver above 500Hz.
However, Mr. Dickason choose the XR2064C for horn duties. It's a nice horn, but not suitable for a crossover below 800Hz.
In order to make this combo work, you'll likely have to resort to 48dB slopes. I doubt the B&Cs midrange gets anywhere near the 15PR400's tranquility.

Finally, in box with some BSC applied, the B&C likely ends up with a sensitivity around 90dB.

Without doubt his monitor needs huge amounts of power in order to come to life.
Mr. Dickason is a knowledgable engineer, so his monitors will probably sound very nice in the end.
I wouldn't build a 2-way according to this design philosophy though. It's more akin to a scaled up typical HiFi 2-way.
In doing so, some of the merits of large highly efficient (low excursion) drivers are lost.
Attached Images
File Type: jpg 15BG100_8Ω_Pagina_1.jpg (209.5 KB, 333 views)
File Type: jpg 15BG100_8Ω_Pagina_2.jpg (340.6 KB, 306 views)
File Type: jpg 18-Sound_XR2064C_Pagina_1.jpg (263.2 KB, 305 views)
File Type: jpg 18-Sound_XR2064C_Pagina_2.jpg (354.1 KB, 304 views)
File Type: jpg 950PB-8_Pagina_1.jpg (376.2 KB, 297 views)
File Type: jpg 950PB-8_Pagina_2.jpg (440.8 KB, 59 views)

Last edited by Ro808; 28th August 2019 at 05:28 PM.
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Old 28th August 2019, 06:10 PM   #2404
GM is offline GM  United States
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Quote:
Originally Posted by Ro808 View Post
Here's the paradox:
If you look at the response, the huge breakup spike at 1200Hz stands out.
Personally I wouldn't use this driver above 500Hz.
However, Mr. Dickason choose the XR2064C for horn duties. It's a nice horn, but not suitable for a crossover below 800Hz.
In order to make this combo work, you'll likely have to resort to 48dB slopes.
Yeah, these huge peaks are out at the ~5th harmonic, so 36*2^5 = ~1152 Hz/12 dB = ~576 Hz/4th order plus parallel notch filter or 8th order to get close to the theoretical goal of > -25 dB, though considering its 'sprung like a buckboard' construction [tiny Vas] best suited for BLH apps, < ~288 Hz/4th order would be my choice and get a real mid bass [horn] driver.

GM
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Last edited by GM; 28th August 2019 at 06:17 PM.
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Old 28th August 2019, 06:16 PM   #2405
Ro808 is offline Ro808  Netherlands
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Thanks for backing me up on this, GM.
I didn't take a BLH into consideration for this driver.


Sometimes, it's better to reread before posting...

...." I doubt the B&Cs midrange gets anywhere near the 15PR400's tranquility."....
and transparency/openness.

Last edited by Ro808; 28th August 2019 at 06:29 PM.
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Old 29th August 2019, 03:36 AM   #2406
AllenB is online now AllenB  Australia
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Quote:
Originally Posted by Ro808 View Post
his monitors will probably sound very nice in the end.
He could be venturing into new territory, finding things out the hard way?
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Old 29th August 2019, 04:19 AM   #2407
Ro808 is offline Ro808  Netherlands
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That's doubtful, considering his level of knowledge and experience, even though his "Loudspeaker Design Cookbook" deals primarily with low sensitivity hifi loudspeakers.

It's probably a matter of design approach/philosophy.

Last edited by Ro808; 29th August 2019 at 04:32 AM.
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Old 29th August 2019, 05:20 AM   #2408
camplo is online now camplo
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Originally Posted by Ro808 View Post
The η₀ of 0.8% speaks for itself.
Ro808 what the heck is this..... I don’t even know how to make that character, but I really want to understand what you are talking about.

GM you didn’t engage my last response regarding polars, TMM, and frequency response in the near field =( I guess my responses must be on point and you’ve made your point clear that you are only in support of a MTM....I know you are right. It does seem that if we follow the 3+\- mm rule for Xmax that a dedicated subwoofer is a must.

Last edited by camplo; 29th August 2019 at 05:23 AM.
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Old 29th August 2019, 07:28 AM   #2409
GM is offline GM  United States
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Originally Posted by Ro808 View Post
Thanks for backing me up on this, GM.
I didn't take a BLH into consideration for this driver.


Sometimes, it's better to reread before posting...

...." I doubt the B&Cs midrange gets anywhere near the 15PR400's tranquility."....
and transparency/openness.
When you're right, you're right!

Apparently doesn't help me much no matter how many times I [re]read/revise/correct my offline composed responses as way too many still need more once posted.

GM
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Old 29th August 2019, 07:57 AM   #2410
phase_accurate is offline phase_accurate
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I was considering that 15BG100 woofer a few years ago for a large three-way D'appolito. I guess when midrange is kept away from it it is a very nice driver.

regards

Charles
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