04-12-15: Ricred1
I recently added the Bricasti M1 DAC. The M1 improved bass output, dynamics, and soundstaging. I still believe I can improve the bass output, but would like opinions on the most feasible way forward. In general I don't like subs. In addition, I don't have a preamp.
04-13-15: Almarg
Richard, as I recall from one of your other threads not long ago you achieved a substantial improvement in bass performance via some revisions to how your bass traps are arranged. And you apparently achieved further improvement in bass performance by going to the M1 DAC.
in light of the OP's response to what his goals were re. upgrading & Almarg's comment that room treatment was tweaked to improve bass & looking at Ricred1's room photos, one reason that bass could be lacking is because the mids & highs could be emphasized by not having those French doors covered during listening. IOW, Ricred1 could be experiencing less bass due to (1) the amp outputting not enough power in the bass freq or (2) the sonic spectrum being tipped up.
There's a lot of uncovered glass on those French doors that could mess up (i.e. tip up) the freq spectrum in your listening room. How about trying to cover up the French doors & see what that does towards balancing the freq spectrum in your room?
I also found a Stereophile review of your Aerial 7T speakers where they did some measurements:
http://www.stereophile.com/content/aerial-acoustics-model-7t-loudspeaker-measurements
The manuf specs the speaker to be 28Hz-25KHz +/-2dB but.........
take a look at the resistance & phase plots on the measurements page (link provided above) - see Fig 1: you can see that for freq 70Hz-200Hz the speaker is essentially inductive (voltage leading current & max voltage would mean minimum current). This would seem to suggest that large voltages in the mid-bass region wouldn't get as much current as they might require so mid-bass definition could potentially suffer. For freq < 70Hz the speaker is essentially capacitative (voltage lagging current & min voltage would mean max current). This would seem to suggest that even small voltages in the bass region could potentially receive large enough currents to output sufficient bass SPL. This would be the bass thump you feel which is what you want for the bass. You want bass definition for the mid-bass & that might be lacking for the reasons above.
Look at Fig 3: look at the blue curve. There's a huge suck-out at 30Hz. looks like this is the resonant freq of the bass driver (?). Also look at the roll-off in the bass driver output below 50Hz - it rolls off sharply. It's already -1dB at 50Hz & -5dB at 40Hz. I would say that at 55Hz & above the bass driver output is not rolled off. Due to this I don't believe that the manuf spec of 28Hz - 25KHz is true w.r.t. the 28Hz. it doesn't look like this speaker can output sufficient SPL at 28Hz with such a rolled off woofer response. No wonder you are considering adding subwoofers - makes sense that you want to augment the deep bass. I'm sure that the rear port will augment the bass but remember that a bass port is always 180 out-of-phase with the bass driver. Putting the port on the rear probably helps correct some of this out-of-phase behavior (not sure tho'???).
Another thing - as others have suggested you should try moving your listening seat back/forth just to ensure you are not sitting in a bass null region. And, as written above, take care of those 1st reflections off the French door - they could be messing things up more than you think.
To me it looks like your speaker is the weaker link between the Rowland amp & the speaker. Thanks. FWIW.
