Ssp 800

[Masterlu]

hifiaudio2... Welcome!

[KahunaCanuck]

From the B&W Support website:

PARAMETRIC EQ
How does the PEQ work?
What is often erroneously called "room correction" is based on parametric equalization, which is the use of filters to "correct" for the effects of the room itself on the overall amount of each frequency being heard at the listening position. As sound bounces around the room some frequencies add and reinforce each other while others cancel each other out. Moving the loudspeaker and/or the listening position can have a major impact on which frequencies are being reinforced and which are being canceled , as well as the degree to which this is occurring. You can think of the correction that is applied as countering the effects of the room by adding to or reducing the level of different frequencies to counteract the effects of the room. Therefore where the room introduces a peak, the PEQ cancels it out by introducing an inverse and equal trough.

Parametric is defined as the changing of parameters and there are three filter parameters to adjust: center frequency (which is the target frequency, usually the highest or lowest point in the peak or trough), the gain (which is how much you are attenuating or increasing the signal) and the Q which is the width or steepness of the filter shape (which is how sharply the filter affects the frequencies around the target frequency). Higher Q means a steeper, more narrow range of frequencies are being adjusted than with a lower Q setting. Generally, lower Q adjustments are more easily heard because they have an effect over a wider band of frequencies. Similarly, narrow band peaks or troughs in the natural room response are not as audible or troublesome as broad, lower Q peaks and troughs. Therefore, as a rule, adjustments to counter low Q, broad band room effects are the most necessary and desirable.

The standard EQ filter is a peaking filter which is what our PEQ is based on. We use these very flexibly since you have 5 filters or bands which can be combined or used individually for each loudspeaker in the system.

Is the PEQ automatic?
No, we don't use automatic room correction. Anyone concerned that this decision will result in the SSP sounding worse than a competing processor with automatic room correction may be misunderstanding of the power of equalization to "correct" a room and the ability of automatic systems to achieve the best results.

The sonic performance of any processor is defined by its ability to maintain the resolution of the incoming signal. No equalization system, even a manual one in the hands of a master acoustician, can compensate for a loss of resolution.

In this context, a processor with perfect equalization but resolution loss will sound worse than a processor with no equalization but which maintains perfect signal integrity. This ultimately means that equalization is secondary to fidelity.

There are other limitations to consider as well. A speaker with poor off-axis response will have more distortion or worse frequency response for sounds that reflect off room boundaries compared with the direct (on-axis) sounds arriving at your ears first. Measuring the frequency response at the listening position can only reveal the total amount of sound pressure at each frequency and adjusting the equalizer to achieve a flat or target curve response cannot change how much of the total sound is reflected, where it is reflected from or the quality of that reflected sound. In other words, equalization cannot correct for the fact that your speakers may have poor off axis response or be poorly positioned in the room.

Imagine also a listening room with a very hard, reflective surface on the right side and a very absorptive, non-reflective surface on the left side. Together, the total amount of reflected energy might produce a smooth frequency response without EQ, yet the differences in reflection will detract from the fidelity of the system and be distracting to the listener. You could also imagine a room where the right side wall is very close to the listener compared to the left side wall. The frequency response at the listening position might be good without EQ, but the early reflections from the right may arrive so soon after the direct sound as to impair the clarity and fidelity of the system. There is no way to truly "correct" for these types of acoustic situations, so it is important to understand the limitations of equalization.

A final consideration on "room correction" is what is called time domain response. This refers to the time it takes for sounds to be reflected back to the listening position and the time it takes reflected sounds to decay in the room. Both vary by frequency and it is possible to make adjustments to try to counter time domain problems in the room, but like frequency domain equalization, the same types of acoustic limitations apply.

The conclusion is therefore to understand the importance of starting with high quality components and loudspeakers, position them as best you can in the room and deal with acoustic problems at their source before trying to employ equalization.

The implied promise of Automatic EQ systems is that a layman may set up a microphone, press a button and have a computer algorithm assess and then correct for the response of the room. As discussed above, whether automatic or not, there are real limitations to how effective "correction" can really be. So the question is not whether the room can be corrected, but within the limitations of correction, how is the best way to do it? Classe's position is that the best results are achieved by employing experienced acousticians. Their knowledge and experience enables human judgment to supplement the measurements, helping them arrive at the final adjustments for best performance. By comparison, we see automatic systems which cannot arrive at the same correction curve twice, and where no two systems ever agree on the adjustments to be made. So which is best? Automatic systems may indeed improve the performance of an otherwise good, un-equalized system, but that is not the same as saying they can actually correct for the room response or optimize the performance of the system.

How do I use the manual PEQ?
There is no easy way to teach yourself to properly use the PEQ, which is why we recommend hiring a professional. If you use a spectrum analyzer and test tones or white noise, you might be able to pick out a few offending peaks and through trial and error, tame them, but to do it right you really need to hire an acoustician who's got the tools, knowledge and experience. A lot of dealers are interested in the subject and some are self-taught and may be quite capable, but it's human judgment backed by both knowledge and experience that ultimately will deliver the optimum results.

To access the PEQ press MENU/ SYSTEM SET UP/ ROOM EQ. You then highlight the speakers that you want to equalize and press select. You then have 5 bands to adjust per speaker. There are 3 values. G is the gain, showing how much you want to attenuate or increase the level. F is the frequency that you want to address. The Q value is the ratio of the center frequency to the 3dB bandwidth and is therefore frequency dependent. A table detailing the filter width for each Q value at each frequency is available from Classe.

Each band may be enabled/disabled. Similarly, the "activate group" function allows you to enable and disable the entire group of EQ settings that you have applied on that speaker. If the group is not activated then no EQ is applied to that speaker. Similarly, the "Activate EQ" button allows you to enable and disable the EQ setting for the entire system.

Given the limitations of equalization, it is generally agreed that the PEQ is best employed primarily to reduce the peaks in bass response called room modes. Adjustments below about 350 Hz are the most important and trying to address issues above that frequency may be unsuccessful or counter productive. From time to time a higher frequency rattle or vibration mode may need to be addressed by identifying the frequency and building a filter with very high Q to surgically remove the source of excitation. But for most applications it is recommended that you stay away from high frequency corrections and focus on the room modes.

The height, width and depth dimensions of a room often result in reflected acoustic waves arriving at the listening position and adding to or reinforcing each other at three specific frequencies related to the wavelength of the sounds corresponding to the various room dimensions. The PEQ may be used to attenuate the output of the system at those frequencies to reduce masking effects and improve overall clarity and intelligibility from the system.

The PEQ is used to help compensate for your environment (the acoustic interaction of loudspeakers and the boundaries, furnishings, etc. in your room). A single set of EQ settings is therefore applied equally to all processed sources, post processing modes and configurations. However the PEQ is a feature of the unit's DSP and therefore does not affect analog inputs that are set to "Bypass Select," or the multichannel analog inputs, which are hardwired in bypass mode.

Why is the PEQ gain limited to +3dB?
Variations in the frequency response caused by room acoustics are the result of many direct and reflected acoustic waves arriving at the listening position at the same time and either reinforcing or canceling each other. If they reinforce each other, it is a relatively simple matter to attenuate the output of the system at that frequency to achieve a net response which is more flat or closer to a desired target curve. If they cancel each other however, an entirely different problem exists.

Imagine the peak of a wave and the trough of another wave being the exact same frequency and amplitude, arriving at the same time. They would sum together and cancel each other entirely. If you amplified that frequency, you would just have two larger waves cancelling each other. So boosting a frequency is not an effective way to fill troughs in the signal caused by wave cancellations. For this reason, there is not much point in trying to provide a large range of gain for the PEQ on the plus side.

There are also technical considerations which impose a practical limit in the gain one would want to accommodate in a PEQ system. + 3dB is the maximum gain we can introduce without reducing the quality of a 24-bit signal. The only we way to add more gain would be to attenuate the incoming digital signal, effectively reducing the dynamic range. We do not want to do this since it would conflict with our overriding aim of preserving the integrity of the incoming signal.

[hifiaudio2]

Thanks! I assume that means I can choose any frequencies I want. Up to 5 a channel. Sounds like it.

[Acolcer]

Hi Folks-

I am new to this forum. Wondering if anyone has experience in comparing any sound improvement with balanced interconnects versus RCA interconnects (2M in length) between the SSP-800 and a DAC or monoblocks. Looking for some tweaks and would appreciate any feedback.

Thanks
Al

[jdandy]

Acolcer.......Al, welcome to Audio Aficionado.

[Acolcer]

Originally Posted by jdandy

Acolcer.......Al, welcome to Audio Aficionado.

Thanks Dan - I see you have sub stands for your JL Audio subs. Are they the ones from Ivan? Everyone here seems to have them. What are your impressions?

[Sonic]

Hey everyone,

Is there a stereo + sub option in the SSP-800? I could've sworn I read something about that feature in a review but have been unsuccessful in locating it in any of the menus. This would be great, as I have been wanting to do 2.1 music. Thanks in advance for any help on this.

[wildtangent]

Originally Posted by Sonic

Hey everyone,

Is there a stereo + sub option in the SSP-800? I could've sworn I read something about that feature in a review but have been unsuccessful in locating it in any of the menus. This would be great, as I have been wanting to do 2.1 music. Thanks in advance for any help on this.

The way to do this through the configurations. There are six fully configurable ones available.
Depending on the way you want the main speakers to operate do one of the following.
If you want the mains band limited with low frequency content redirected to the sub make the front speakers small and turn on the sub-woofer. If you want the fronts full range and bass content sent to the sub as well make the fronts large turn on the sub and enable e-bass.
This new configuration can then be assigned as the default to a source.

[Masterlu]

wildtangent... Welcome!

[Sonic]

Originally Posted by wildtangent

The way to do this through the configurations. There are six fully configurable ones available.
Depending on the way you want the main speakers to operate do one of the following.
If you want the mains band limited with low frequency content redirected to the sub make the front speakers small and turn on the sub-woofer. If you want the fronts full range and bass content sent to the sub as well make the fronts large turn on the sub and enable e-bass.
This new configuration can then be assigned as the default to a source.

Thanks much!!

I noticed also that when playing music I had to go in and change the input connector from HDMI Audio for movies to Analog 1 XLR. Is there an easier way to toggle between them or a way to program what input connector to use for certain content (DVD-A & CD = Analog XLR and BD = HDMI Audio) so that I don't have to go in and manually switch each time? The closest I've gotten is possibly using an F-button to skip directly to the input connector menu. I play music and movies from the same source.

Thanks again!!