Dayton RS150-S8 MTMFor Home Theater or Music

The ported tower will extend a bit deeper (it's tuned to ~37hZ stuffed with about half a pound of poly or less). Both will peak out at around 1.5W and a max output level of ~92dB if there is any significant bass below 40Hz. The smaller cabinet ported has slightly more power handling with a ~42hZ port tuning (stuff with about a quarter pound of poly, or less). The sealed box fares a bit better on power handling and will peak out at about 98dB. I have run into this in a few instances at what should be well under max levels, but I was also not listening with my SPL meter running - and I may have just done the "ooh, this one is good... gotta crank it a little more" just a bit too much. Still, these are really best suited to use with a good subwoofer if you are into heavy bass at high levels. My normal listening level is usually peaking at 75-80dB but with normal playback 65-68dB (at 3 Meters) and the clarity and detail of these excels here.

!You can not use the shielded tweeter and expect this to work correctly.

With the unshielded version of this tweeter, this circuit includes full baffle step. This is a 4ohm nominal speaker.

With the shielded version of this tweeter, this circuit includes full baffle step. This is a 4ohm nominal speaker.

!This is for the shielded version only.

With the shielded version of this tweeter - if you're using this tweeter, you're probably placing it in a situation where you don't want full baffle step. Use the following network instead. Use 20ga inductors (a little more series resistance) if you're placing this in a cabinet - if it's just on top of a TV, use 18ga.

Note that all measurements are un-smoothed (except impedance, which is 1/16 octave smoothed). Also note, these measurements were with some bad gates set (I thought I had cleared them but after going back and checking my settings, turns out I had a gate wherever my mouse drag/drop placed it) - after more testing in a different room with more care taken the big bump at the bottom end is not actually a big bump. The speaker has the gentle roll-off on the bottom end that I expected to see. I took care to set the gates properly and Speaker Workshop was behaving like I expected it to be have as I changed settings. Due to time constraints I did not do the extensive re-testing to update the measurement graphics, so that will have to wait till another day. In the mean time, trust that this speaker is, with a couple exceptions, flat on-axis +/- 2dB, from about 44Hz-20kHz+. I hope to eventually get around to re-measuring in full detail. But I have to have the house to myself for that. And one final note - the spritz at 12kHz is the result of a flaky solder joint.

To start with, a comparison of this speaker measured on-axis at 1M vertically (Yellow), horizontally (red), and the predicted response based on available data files (green). Predicted response using measured response follows almost perfectly, except that it's up about 3dB. I believe the difference is largely due to the fact that I measured each driver in the enclosure with the other driver still present, which produces some, well... interesting results.

Impedance of the finished speaker. Box tuning turns out to be a few Hz below my target, and is at about 38Hz. Measuring the port confirms this. I suspect that I have overstuffed the enclosure and will experiment with this.

Of course, we must do off-axis measuremens to be thorough. The top graph is off-axis to the tweeter side, with the bottom graph being off-axis to the other side. This is in Vertical mode. Fairly satisfying, as there is relatively little sag around the crossover region - 60° off-axis is only down about 5dB. Even the tweeter is good through about 12kHz this far off-axis, meaning that it should be surprisingly listenable at this point. On-Axis (yellow), 15° off-axis (red), 30° off-axis (green), 45° off-axis (pink), and 60° off-axis (blue). Note that this suggests that putting the tweeter to the outside would provide the best results - indeed, my ears suggested this, so it is satisfying to see measurements in support. The tweeter rolloff 30° off-axis with the tweeter on the outside is as smooth as just 15° off-axis with the tweeter on the inside. And from 1kHz to 4kHz stays pretty much solid throughout.

This is where it gets a little ugly. Off-axis measurements with the speaker horizontally placed, as it would be when used as a center channel. If you remain witn 15-20° off-axis at the edges I think that there will be no trouble. For most folks sitting on a couch 2-3M back, this is reasonable. However, as you can see the off-axis measurements at 30° and above are rather dismal. On-Axis (yellow), 15° off-axis (red), 30° off-axis (green), 45° off-axis (pink), and 60° off-axis (blue).

April 14 2005: New versions using the RS28A-4 tweeter! Lower crossover point, better power response, and what should be improved off-axis response when placed horizontally.

January 14, 2006: New version using the Seas 27TDFC and a lower crossover point. Should have similar traits ot the RS28A version as far as power response and horizontal off-axis response.

April 24, 2007: Complete revamp of this page! Hopefully it is significantly easier to find what you're looking for. New generic crossover variants for the Seas tweeter family.

April 29, 2007: Updated crossover diagrams, BOM's, and box design (tower is finally corrected)