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I need some advice, JBL DD66000,Beolab 50 or KEF Blade One Meta?

Absolute

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First of all they are not small. We are talking about 10" wide 5m long tubes...

Secondly, surface area is not a criteria, room dimensions are.
In that case I still believe it's ineffective compared to the necessary real-estate taken. :D
 

sarumbear

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In that case I still believe it's ineffective compared to the necessary real-estate taken. :D
They are inside the suspended ceiling, what real estate?
 

sarumbear

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You also need on one sidewall and front or back wall from pressure points between opposite surfaces?
I'm afraid it looks like you do not understand room modes. This is a good source. All you need to do is to place the resonator where the standing wave's SPL is at its maximum, these are often corners and ceilings are nearest to the corners, equally as the floor but without using any "real estate."
 
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Absolute

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I'm afraid it looks like you do not understand room modes. This is a good source. All you need to do is to place the resonator where the standing wave's SPL is at its maximum, these are often corners and ceilings are nearest to the corners, equally as the floor but without using any "real estate."
My backwall is 7 meters long and the spl on the 44 hz mode is highest all the way along it. What I'm asking is do I need a 7m long Helmholtz on this wall for it to be effective?
 

sarumbear

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My backwall is 7 meters long and the spl on the 44 hz mode is highest all the way along it. What I'm asking is do I need a 7m long Helmholtz on this wall for it to be effective?
Its strange that the SPL of a room mode doesn't increase in corners. How are you measuring? What is your source?

Resonators can be any shape and their size effects their absorption capacity. You can calculate resonators here. A 10" tube which is 1m long will resonate at around 44Hz with a 5cm radius and 6cm vent.
 

Ra1zel

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I would go for DD66000 and modify them into actives ¯\_(ツ)_/¯


Salon2 being a cleaner sound (narrower baffle-> less diffraction)
I don't think baffle has anything to do with that, just cleaner drivers used, and Salon2 simply has higher "Prefernce score" from spinorama
Why would low sensitivity is a trade off when amplifier power is abundant? A 70W stereo amplifier will produce more than 100dB at a 3m listening position, with two speakers away from the walls.
Getting loud is no worry indeed but I wonder about long term thermal compression
 

Ra1zel

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is that a thing?
I'm not sure, that's why I wonder if it is. If more power is dissipated in the voice coil it must get hotter than more efficient systems... probably doesn't matter at rational volume leves.
 

Absolute

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Its strange that the SPL of a room mode doesn't increase in corners. How are you measuring? What is your source?

Resonators can be any shape and their size effects their absorption capacity. You can calculate resonators here. A 10" tube which is 1m long will resonate at around 44Hz with a 5cm radius and 6cm vent.
I'd have to measure again to check the difference, but it will be higher in the corners. The corners between floor/wall and wall/ceiling are awfully long though, which is why I I'm curious if you'd need 7 meter long traps to make it effective.

I'm not arguing about helmholtz resonators and their effect, I'm questioning the effectiveness of them compared to other things, like a small number of subs distributed and made to even the response in the whole room - inluding every variant like active basstraps, arrays etc - relative to the space, effort, cost and trade-offs.

My take on it is that the HH requires the specific space where the mode is strongest and all the space it needs to be effective at that single frequency. This is space that could be needed for absorption of other frequencies, especially further up in the bass range where we are far more sensitive to the time domain. In contrast a much smaller sub could be placed there and played in opposite phase at more than one single frequency with the help of FIR, allowing more flexibility and even increasing capacity if needed in other parts of the range.

To me this isn't about whether or not something works in itself, it's about the trade-offs we have to consider. I like your solution of putting them in suspended ceiling and inside false walls, but I still question the effectiveness compared to using that space for broadband absorption, more bass drivers, diffusion or other cool stuff.
If you say 5 hidden HH evens the response from a 22 dB span down to a 7 dB span I believe you, I'm just curious whether or not you can achieve a better result in a broader sense in other, possibly easier, ways.
 

sarumbear

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If you say 5 hidden HH evens the response from a 22 dB span down to a 7 dB span I believe you, I'm just curious whether or not you can achieve a better result in a broader sense in other, possibly easier, ways.
Taking a 12" tube, pre-cut to 5m, placing covers on each end and then inserting a vent is the easiest thing you can do.
 
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dickman

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I would go for DD66000 and modify them into actives ¯\_(ツ)_/¯
On this point, Greg Timbers, the designer of Everest, has mentioned how he uses his DD67000
My system consists of the following:

2-channel:
Everest DD67000, fully active 4-way
DEQX HDP4
DEQX Premate
Pass Labs XVR1
Parasound JC1, 4 amplifiers, 1 for each woofer.
Quicksilver Mono 120, 1 for each large compression driver
Pioneer Elite A-20, for UHF compression driver
Pass Labs XP-15 Phono Stage
Basis Audio Debut Turntable with SuperArm 9 and Dynavector DV-20x
Tascam DA-3000, Digitizing LP's
MacMini running JRiver Media Center 22
PS Audio LanRover
5 microphone array around listening position shows -3 dB @ 20 Hz and -6 dB @ 48 kHz. The 1/6 oct response of the 5 microphone average is less than +/- 1 dB from my target curve over that range. The system sensitivity (if passive) would be 96 dB for 2.83 v @ 1 m. Since the DEQX uses linear Phase (FIR) crossovers, I have the impulse of each individual transducer and its network aligned to less than 0.1 ms at the listening position. EQ and room correction is done in the DEQX, JRiver and the CT-SSP depending on input and overall system configuration. (Music, Phono, Movie}
The microphone test results were significantly better than JBL's claimed 45Hz-60KHz (if that's -6db)
Description: Dual 15" (380mm), three-way, floorstanding speaker
Frequency Response: 29Hz – 60kHz (half space); 45Hz – 60kHz (anechoic)
Recommended Amplifier Power: 500 watts
Sensitivity (2.83V @ 1m): 96dB
Nominal Impedance: 8 ohms; 5.0 ohms @ 80Hz; 3.0 ohms @ 40kHz
Crossover Frequencies (Hz): 150Hz (LF1 6dB/octave) 850Hz (LF2 24dB/octave) 20kHz (UHF 24dB/octave)
I don't fully understand what Greg is doing, it also sounds like he is converting it into active
I wonder if I could achieve the same effect with the same amount of power and a digital DSP processor?:)
 

Ciobi69

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I wish I could find a pair of dd66000 for a fair price here in Europe, the price are really different,the kef blade used is cheaper, the high sensitivity of the JBL really appeal me a lot, but the kef blade are awesome engineered speakers too
 

GXAlan

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I don't fully understand what Greg is doing, it also sounds like he is converting it into active I wonder if I could achieve the same effect with the same amount of power and a digital DSP processor?:)
As with anything, the sky is the limit in terms of cost.

An Accuphase DG-68 and DF-65 and the amplification to go with it will make it turnkey. I don’t know if the DD66000 is the same as the 65000 and 67000 but there is a jumper that you can set on the back

“Setting the shorting bars in the Bi-Amp position requires the addition of an external dividing network (electronic crossover) to provide the 750Hz (DD65000) or 850Hz (DD67000) primary crossover point for the system. The built-in attenuation and equalization for the 476-series high-frequency driver remains in place. The high-frequency level trim control remains operational, as does the diode biasing for both the low-frequency and high-frequency network sections.”

The Accuphase is very expensive but the only way you can EQ something like physical SACDs in the digital domain. Something like a high end MiniDSP can give you the many of those benefits. You are of course paying for the premium analog componentry as well.

That said, the Accuphase setup is my choice if I had that kind of money/budget. It is frivolous/real luxury splurge to go for an Accuphase/JBL Everest setup and I am sure I will get criticized for the recommendation, but you could say the same thing about owners of Ferrari’s or even Porsche Cayenne Turbo’s who drive safely on city streets, owners of platinum Rolex or Patek Phillipe watches, luxury handbags or jewelry…
 

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dickman

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As with anything, the sky is the limit in terms of cost.

An Accuphase DG-68 and DF-65 and the amplification to go with it will make it turnkey. I don’t know if the DD66000 is the same as the 65000 and 67000 but there is a jumper that you can set on the back

“Setting the shorting bars in the Bi-Amp position requires the addition of an external dividing network (electronic crossover) to provide the 750Hz (DD65000) or 850Hz (DD67000) primary crossover point for the system. The built-in attenuation and equalization for the 476-series high-frequency driver remains in place. The high-frequency level trim control remains operational, as does the diode biasing for both the low-frequency and high-frequency network sections.”

The Accuphase is very expensive but the only way you can EQ something like physical SACDs in the digital domain. Something like a high end MiniDSP can give you the many of those benefits. You are of course paying for the premium analog componentry as well.

That said, the Accuphase setup is my choice if I had that kind of money/budget. It is frivolous/real luxury splurge to go for an Accuphase/JBL Everest setup and I am sure I will get criticized for the recommendation, but you could say the same thing about owners of Ferrari’s or even Porsche Cayenne Turbo’s who drive safely on city streets, owners of platinum Rolex or Patek Phillipe watches, luxury handbags or jewelry…
I don't actually have a budget to throw away, and I think the dd66000(also beolab50 and Blade) for under £20,000 is an excellent value for deal, although still very expensive, but for this class of speaker, I would call it a 'bargain'.
If possible, I would have gone for something cheaper to achieve the same results.:)

I wondered if it would be possible to achieve the effect Greg is doing with the editable DSP algorithm built into the AV receiver. A home theatre preamp like the Lyngdorf MP60 or JBL SDP75 can EQ the speakers, so I wonder if I could use this feature to mediate the frequency response curve of the DD66000 to achieve the same effect. This does save the budget for a lot of extra crossovers, if that's possible.
 

GXAlan

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I don't actually have a budget to throw away, and I think the dd66000(also beolab50 and Blade) for under £20,000 is an excellent value for deal, although still very expensive, but for this class of speaker, I would call it a 'bargain'.
If possible, I would have gone for something cheaper to achieve the same results.:)

I wondered if it would be possible to achieve the effect Greg is doing with the editable DSP algorithm built into the AV receiver. A home theatre preamp like the Lyngdorf MP60 or JBL SDP75 can EQ the speakers, so I wonder if I could use this feature to mediate the frequency response curve of the DD66000 to achieve the same effect. This does save the budget for a lot of extra crossovers, if that's possible.

In that case, just run the DD66000 as designed with the passive crossovers. It’s efficient, so you would be fine even with a Denon AVR-X8500H. The Lyngdorf will only do room correction for lower frequencies not full 20-20kHz EQ on top of the RoomPerfect. The SDP-75 will be fine and you can pair it with some good amps. The SINAD of the Trinnov 16 is lower than the X8500H but the Trinnov does it’s room EQ in high resolution where was the Denon decimates to 48 kHz.
 

Tom C

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I think it should be mentioned that 2-channel stereo is in some cases acceptable for home theater playback of movies and other video content. It is simpler, and can be cheaper since it’s only two channels instead of six channels or more.
While it’s true that the center channel is critical in a multichannel system, and the center contains most, if not all the dialogue, it is also true that, most of the time, a dedicated two-channel track is available (whether streaming, cable, satellite or disc is used) that will contain all of the dialogue, and all of the sound, in the L & R channels.
 

Ciobi69

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I think it should be mentioned that 2-channel stereo is in some cases acceptable for home theater playback of movies and other video content. It is simpler, and can be cheaper since it’s only two channels instead of six channels or more.
While it’s true that the center channel is critical in a multichannel system, and the center contains most, if not all the dialogue, it is also true that, most of the time, a dedicated two-channel track is available (whether streaming, cable, satellite or disc is used) that will contain all of the dialogue, and all of the sound, in the L & R channels.
And having high end speakers like the blade or the JBL helps a lot instead of a mediocre multichannel system,but it's a different thing
 
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dickman

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In that case, just run the DD66000 as designed with the passive crossovers. It’s efficient, so you would be fine even with a Denon AVR-X8500H. The Lyngdorf will only do room correction for lower frequencies not full 20-20kHz EQ on top of the RoomPerfect. The SDP-75 will be fine and you can pair it with some good amps. The SINAD of the Trinnov 16 is lower than the X8500H but the Trinnov does it’s room EQ in high resolution where was the Denon decimates to 48 kHz.
I appreciate your advice, you mentioned that the SINAD of the SDP75 is lower than that of the demon, I tried to search the internet for information on this but no luck
It seems that the signal to noise ratio depends on the quality of the DAC chip, I've heard that Trinnov (also SDP75) handles the decoding exclusively in software, Intel's i7 CPU is responsible for the software, which means that the SDP75 doesn't use a hardware DAC chip, I don't know if that means good or bad
 
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dickman

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Another thing I wonder is how Greg can get far better test results than JBL's claimed curve, especially in the low end
-3 dB @ 20 Hz and -6 dB @ 48 kHz. The 1/6 oct response of the 5 microphone average is less than +/- 1 dB from my target curve over that range
View attachment 219973
Greg seems to have used a crossover and additional amplifiers to achieve this, each woofer has 300W of power, which is already more than the maximum 500W recommended by the DD67000

I checked some information about the DD67000's woofers and although I'm not capable of reading these different test results, it seems to indicate that with enough power the woofers can provide better low frequency extension

I wonder if the same effect can be obtained by using the DSP of the AV receiver directly without the crossover
Is there a possibility of burning the tweeters if they are supplied with too much power without using a crossover?
 
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