Your sub experience: Easy or hard?

@kevn The DBA setup is more accurate. The single sub suffers a bit around the edges of the room where it gets too much reinforcement. Forward or downfiring has no effect (in practice) simply because in most rooms the bass is entirely reverberant by the time you hear it due to the wavelengths involved (at 80Hz the wavelength is 14 feet).

Thanks for your quick reply, Ralph! : ) - kevin.

@jrpnde , nice article and very correct. A sub not only has to match the mains in frequency response but also in time. This is the problem with DBA's. They do a great job of evening out the bass response throughout the room. But, they are not necessarily and probably not matched in time with the main speakers. You have to be in phase and in time with the main speakers or you have essentially an echo. Bass transients like bass drums lose their impact. The buzz in bass strings disappears. The only way you can do this easily is with digital signal processing. The Anthem system was mentioned above. MiniDSP makes the least expensive unit that I know of. There is Trinnov, DEQX and Lyngdorf. People who are digiphobes need not apply and more than likely would be better off without subwoofers. You can not recreate a live performance without subwoofers. To do it right takes much more driver surface area than you would think. Residential rooms stifle bass. Add a processor to this and you have considerable expense. If you can not do it right you are more than likely better off from a sonic perspective not to do it at all. You can kiss the live performance goodbye but this is not what most people want anyway. They want a more polite system that is very detailed. They rarely listen over 85 dB and bass loses it's energy at this volume subwoofers or no. 

Another important aspect of subs is that they take the load off the main speakers which can make serious improvements with their performance in terms of distortion and headroom. Good subs do not low pass at 40 Hz. They are used in conjunction with a high pass filter on the mains and cross between 80 and 120 Hz then time corrected usually by delaying the signal getting to the main speaker so the group delays match at the listening position. You have no idea what is happening unless you measure it. If you think you can do it by ear, good luck to you. Getting it right would be like winning the lottery. Like everything else in this life there are no cheap easy solutions only people who want to sell cheap easy solutions. 

Sorry for preaching.

Just want to repeat my request to please keep the thread on topic by focusing on:

• Personal experiences
• Difficulty of getting to done.

If we veer too much into theory and pro’s cons of any particular solution this thread will rapidly degrade.  Fortunately those interested in debating the pros and cons of any particular solution can pursue that by creating new threads.

Thank you,

Erik

nice article and very correct. A sub not only has to match the mains in frequency response but also in time. This is the problem with DBA's. They do a great job of evening out the bass response throughout the room. But, they are not necessarily and probably not matched in time with the main speakers. You have to be in phase and in time with the main speakers or you have essentially an echo. Bass transients like bass drums lose their impact. The buzz in bass strings disappears.

@mijostyn This is mostly incorrect unless you let the subs run up too high. At lower frequencies the 'time alignment' thing isn't an issue simply due to the length of the waveform. At 80Hz its 14 feet long and that means in most rooms its bounced off the wall behind you before the you can even know what the bass note even is (it takes a few iterations of the note before the ear can identify the frequency). By the time you've identified the note, the bass in the room is entirely 100% reverberant- there's no time thing. So yes: ALL bass in regular size room below probably about 80Hz is an 'echo'.

FWIW this is the case whether you have a single sub or a DBA or anywhere in between.

I play string bass; have since I was in 6th grade. The 'buzz' in bass strings comes from harmonics of the instrument, not its fundamentals; the former are handled by the main speakers.

A DBA has no adverse effect on bass impact (if you have a standing wave at the listening position it can certainly improve it); at any rate regardless of the subs you have if they (or it) allow proper bass at the listening position then the bass will be the same in either event regardless of single or multiple subs.