Subwoofers.... one 10" or two 8"?

@larstusor

It means a lot of things, but in general it means making sure that each driver you are listening to blends seamlessly with others despite being located at different distances from the listener.  It matters in multi-way speakers as well as in integrating a subwoofer with a main speaker. This really is "phase alignment" but in use it's often called "time aligned." 

In flat baffle designs, each driver has a different acoustic distance from the listener. Phase alignment means you've taken that and the phase of the crossovers into account so that the frequency response has no dips/valleys where they meet.  Here is an example from a speaker I designed, the LM-1.  Look at the second and last chart for more information. 

At it's most stringent, time alignment may mean having a perfect impulse or step response.  Van DerSteen is famous for this type of design.  Look at the step response in Stereophile's review of the Seven and compare it to the LM-1.  Thiel is also a manufacturer that specialized in time-alignment.

Best,


Erik

Hey eric 
. Aren't  reflection points playing a big role there also . When i used treatment on the points . The ole mirror reflection spot gik talks about it helped immensely. Op cant run treatment though 

@oleschool

Um, not sure the context, but true subwoofers have no real reflection points, the waves are so big that a reflection point would be around 10’ wide. At the mid to high frequencies where the wavelength is near or smaller than the driver dimension, sound travels like rays, so reflection points in a room matter a lot and are easy to treat with conventional panels and diffusers.

On top of that, most panels are completely ineffective below 300-400 Hz. Instead we rely on bass traps placed in corners where the maximum pressure points occur. Even a lot of "bass traps" don’t go much lower than 120 Hz, and below that is where the big issues occur. In this area, the GIK Soffit traps are unbeatable for effectiveness and cost. 

Best,


Erik

@leotis 
Your 8/13 2:27AM post seems very helpful.  THANK YOU.

I'm planning to try it integrating SVS SB1000s with Silverline Prelude Pluses that claim a lower end of mid 30s Hz.  

For anyone interested, an on-line tone generator is available at the link below.

http://www.szynalski.com/tone-generator/

Eric sorry i was speaking in broad terms like mids etc I suggested gik bas traps i use them and with a few other panels an diffusers it changed my game . Gik was just saying in general terms have a freind hold a mirror for you against the reflection wall until you see your speaker and start by treating that area with a panel etc . Obviously not accurate for all app my speakers are 4’ from the side walls corners are trapped . This all becomes meaningless if treatment is not an option
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    Ghosthouse just curious why the svs no gripe or pro for it just curious for your decision over others