SO PLEASE, if possible, do the "crawl around" test. That's the next step.

THE CRAWL-AROUND TEST: USING BONUS FREE Tracks 22, 23, 24 - Techmaster PEB   Newtown Records and Techmaster PEB were at the heart of the Bass Revolution. Their work remains at the top of every list: engineering, musicality, style, quality, production. Track 24 is the Ultimate Bass test. If your system cannot play this at 110 dB it is either set up incorrectly or you need JL Audio Subwoofers!  You can damage ANY brand of sub with these tracks if abused. Be careful!

Track 24 is very helpful for the "crawl-around" test because it covers many frequencies AND it is repetitive. Place one sub AT YOUR LISTENING POSITION, FACING FORWARD. Using the analog outputs of a CD player, plug them directly into the sub. Turn the sub's filters to off, and the e.l.f. trim to "0". Manually adjust the volume level of the sub to a good 85 dB or so. Now crawl around the perimiter of the room, and listen for the various couplings of the sub. You should notice a few areas where the bass is thin and weak (the nulls) a couple of areas where the bass is boomy and the fundamentals are louder than the harmonics (often too much corner gain) and then a couple of spots (2 or 4 places) where the bass sounds GREAT! Those are the spot(s) to put the subs so they inverse couple the best to your listening chair. You can't fight with the laws of physics!

THEN, if you have JL Audio subs, adjust the ARO for EACH sub relative to its position in the room, THEN adjust the phase relationship between the sub and its main channel using the method outlined below. However, as a suggestion, you might want to NOT USE any ARO or other computer setting (such as Audyssey) until you LEARN the characteristics of your system at its neutral settings FIRST. Then you may wish to experiment by making ONE change at a time, or ONE computer "adjustment run" at a time. It is very difficult to determine a result if you change more than one thing at a time.

All modern, powered, sealed subs have a phenomena called group delay so to best integrate sub(s) you must fix that timing issue so the sub lines up in time with the mains at the crossover point. Since you cannot remove this inherent delay in the sub you must add this delay to all the top channels. You do this by manually setting the speaker distance settings in the setup menu. I suggest setting all the distance settings THE SAME and to a LOW number (for example 7 feet; then add 12 feet to the SUB distance only (so the sub distance now = 19 feet). Now you have added the correct amount of delay to the REST of the system (the L C R Ls Rs) so you can then properly FINE TUNE the sub's phase with the mains by adjusting the phase knob and polarity switch on the sub. Therefore you have added just a bit more delay to the tops to give you a space for a fine-tuning adjustment on the sub to sharpen the focus. This will give you the best possible impulse response through the entire system; the imaging and focus should then should be uncanny, and the bass focused and as tight as possible. If this is done correctly, even if the subs are behind you, you will NOT localize them; it will seem as if the bass is playing from the front of the room, where it belongs, and this is true even if the crossover frequency is as high as 120 Hz.

Deciding on the crossover freqency: I suggest never going below 80, even if you think your speakers go down to 40, or below. Even in a room where the existing "mains" have a pair of 12" drivers (each) you will get far better results if you correctly seal the ports and cross them over at 80, and of course you MUST match the phase and timing relationship or the whole transition is not valid. For Home Theater setups set the Mains=SMALL, Sub=YES, XOVER=80 Hz and if you have a choice, 24dB/octave. Feed each sub with the same signal placing "Y" cords anywhere. For JL Audio subs, if the room is symmetrical and everything in it is placed symmetrically you may use the master/slave system, but it is better (and yes, more work) to use each sub as a master and then adjust the phase of each to match with the mains carefully.

If you have a 2-channel only system if you do not correctly use a crossover you are both wasting your time and you will be frustrated. You simply CANNOT correctly and flawlessly match a modern, sealed sub to an existing so-called full range, probably ported speaker system unless it is matched. But you be the judge. At least with this test CD you have a guide to work with.

Next we set the phase.

TRACK 8:  80 Hz, 2 min @ -1dBfs  Using 80 Hz is an easy way to set the relative phase of the JL Audio subwoofers to match the "mains", especially if you are using 80 Hz as the crossover freq, such as when connecting to a Home Theater receiver. However, whether or not you are using a bass managed HT system, or a separate crossover, this method is still very useful.

Method A (easier, but less accurate)  After you have placed the sub where you want it, put YOUR HEAD equidistant between the sub and the speaker it is CLOSEST TO (for example the LEFT FRONT). Disconnect the 'other' front speaker. Play the 80 Hz tone and adjust the PHASE CONTROL of the sub and the POLARITY SWITCH until the bass is loudest and cleanest - in other words, the peak.

Method B (more accurate, and more work...)  Invert the polarity of the MAIN speaker the sub is CLOSEST TO. Disconnect all the other speakers in the room. Place your head equidistant between the sub and the speaker it is closest to. Play the 80 Hz tone. Adjust the phase control until you hear a distinct NULL. (IT MIGHT EVEN DISAPPEAR COMPLETELY) If you can't get a null then flip the POLARITY switch on the JL sub and adjust the phase control again. There should be some setting of the two controls on the JL sub which will provide a rather sharp null - in fact you might be amazed at how easily and completely the bass cancels. Now put the wiring back the correct way to that one speaker. Reconnect the other speaker and you're done.

If your speakers are ported, you SHOULD close the ports. Towels will do for a test but you might consider purchasing a 3", 4", or 5" thick slab of "foam" at a notions / sewing store; then using a suitable circle template (food can, peanut butter jar, etc) mark the foam and cut with a bread knife slowly. Then spray paint with flat black barbecue paint and you will have a professional port seal. Some better brands of speakers (B&W for example) come with port plugs for just this purpose. What you are trying to accomplish is to NOT have multiple sources of differing phase relationships (the main driver, the port air, and the sub driver) at 80 Hz. The filter slope of both the sub and the mains should be a mirror image in both the frequency and phase domain, and there should only be two LF sources you are attempting to couple: the LF driver in your main speaker and the driver in the sub cabinet.

If you have 2 subs repeat either of the above procedures with the mains speaker the 2nd sub is closest to. All the sinewave tone tracks are recorded exactly the same on both chanels therefore you can disconnect either L or R speaker for your convenience.

The REASON for Method B?   When 2 waveforms are IN PHASE and they sum they may get 6dB louder, but when 2 signals are OUT OF PHASE and they sum, theoretically they cancel completely, therefore It is much easier to hear the NULL. In practice, LF signals coming from 2 spots in a room won't sum 6dB louder; they will sum perhaps 4 or 5 dB louder, because in a home size room the summation also includes the summation / cancellation of various standing waves and reflections.

Further note: if you have self powered speakers (such as studio monitors) that have Balanced XLR-type input connections then doing the above test can become difficult, because you cannot reverse the red and black wires because there aren't any!  But I have the easy solution: see my Polarity "Phase Flipper" Interconnect kit, HERE.   (opens into a new window).

After you have successfully matched the phase of the subs to the mains (whether a 2-channel system or a Home Theater system), you are ready to match the level of the subs to the mains. But remember when you are ALL done with this, inasmuch as your "system" is calibrated, there is often a huge difference in the bass level and content between different sources. You may find that DVD's are more consistent and that music CD's are all over the map. You can then arbitrarily determine any reference point you like and work + or - from there; i.e. you might have to turn your subs UP 3dB to play rock CD's and DOWN 2 dB to play SCI-FI movies. It's up to you. Do not think because "it's calibrated" you are stuck with that setting.

Track 19:  LF PRE-CONTOURED Noise at -20dBfs  This Low frequency noise is pre-contoured to be used with a radio Shack or similar meter when setting up a Home Theater receiver which HAS bass management. Leave the volume where it was in the Track 17 test, above, and play this track. Adjust the SUBWOOFER level so the meter (set to SLOW WEIGHTED 'C') matches the 85dB as in the test above. By using these 2 tracks, it is not necessary to do any mathematical or mental conversions... just match the levels at the listening position. Since the SPL in the room is at 85dB, and the recording is at -20, that leaves 20 dB headroom for the Dolby / THX level of 105dB for peaks. (The Radio Shack SPL meter is HERE )

TRACK 1 : Pink Noise LR  2 minutes @ -20dBfs  The L and R channels are IDENTICAL. Because the noise is at -20dB below full scale digital, it represents the same level as "THX" or "Dolby" "reference" level. That means that when your system volume is adjusted "normally" you should get 85dB SPL (slow weighted C of course...) at your sweet spot chair.

This also means the CD is CAPABLE of 20dB MORE, which translates to 105dB SPL. You may use the pink noise for overall SPL measurement. Since the 2 tracks are identical (they are correlated) if you are playing one channel only and you turn on the 2nd channel the room level should (on paper) sum 6 dB. However, as mentioned above, because of phase anomalies and reflections in any given home-sized room, this almost never happens, but you can expect a 4 or 5 dB increase.

TRACK 2 through TRACK 17: Tones @ -1dBfs  These tracks are all recorded 1dB below the MAXIMUM POSSIBLE ON THE CD. PLEASE BE VERY CAREFUL WHEN PLAYING THESE TRACKS. The highest frequencies are first. Start with your system volume very low and move it upward until the desired result is obtained. The REASON these are recorded at this level is so you can determine if your subwoofer (or mains, or headphones, or entire system etc.) is CAPABLE of playing these frequencies and at these levels.

You can therefore determine the maximum possible output from your sub and your entire system — and how it is coupling into your room — at each given frequency. YOU are responsible for the careful and judicious use of these test tones. It is theoretically possible to damage your speakers, your amp(s) or your hearing with the careless use of these test tones or of the Techmaster PEB tracks below. Please be advised.

If, when playing individual bass tones (or the Techmaster PEB tracks, below) you find various objects, air conditioning grilles, drawer pulls, art objects, lamps, neighbors, etc. vibrating then I suggest you get some museum gel to stop their vibration. It's available HERE .

Notice the BLIP is POSITIVE-GOING (only) and the top of the sine wave is exactly at 100%, therefore this represents full possible modulation on the TEST CD, i.e. 0dBfs. When you play this TRACK 26, the end result of the phase of your system, sometimes called absolute polarity, should make the Low Frequency cones move OUTWARD. This is also a fascinating, superb, and rather severe test to determine the delay time of the subwoofer relative to the rest of your system. As carefully outlined in my SUBS white paper, if your sub is 360 degrees (or even 720 degrees) late, you cannot measure it with a frequency-measuring device, and you will think the frequency response is flat but the impulse response will be smeared. That is the most important reason why measuring in the frequency domain is largely a waste of time, unless you FIRST fix the time domain!

Since this signal is at 80 Hz, and your crossover is set to 80 Hz, you should be able to hear this signal from either/both your mains and your sub(s). Therefore if you turn the volume down on the sub(s), you can use this test to determine absolute timing of other parts of the system. This will "rough in" speaker distance timing, and then you can use the WHITE NOISE test (below, and on the white noise page, here: www.soundoctor.com/testcd/whitenoise.htm , to really fine tune.

FREE BONUS Tracks 19 and 20 - Holly Cole   Please purchase every Holly Cole CD you can find !  She deserves it and you will love it. While the recordings themselves are all superb, thay are of a different enough flavor to keep you on your toes. The bass on Jersey Girl is a little bit heavy, and a dB or two too loud. If you carefully adjust your system then you should perceive this. If the bass seems WAY too heavy, or not heavy enough, then I will venture a guess that either or both the phase relationships and the levels of your subs are not set carefully enough.

Don't Smoke in Bed tests the limit of the plain ol' 16 bit process. Her voice should be FLAWLESS and yet the sibilants on many systems might sound flawed - yet the CD is actually clean and the waveforms are pristine. This is a fabulous test track to A-B different connections, i.e. compare the analog vs the coaxial digital vs whatever else your player has for outputs, and choose the cleanest. You can find Holly Cole CD's here: Amazon and HERE . Her website is here: www.hollycole.com While you're looking for Holly Cole recordings try and find any of the now out of print Techmaster PEB CD's. You won't be sorry.