The mighty mouse of audio, aka The REL T5 subwoofer

[DaveyF]

Dafos, I think that the steeper slope will on some material potentially give rise to a "hole" effect. I had noticed that in a friends sub when I auditioned his system. However, that's not the reason that I went with the T5. Instead, I wanted a sub that wouldn't risk overdriving the room and one that was quick on its feet. The GH's are lighting fast in their response time and I didn't want to risk losing that magic. Even with the T5, I do feel that there is a smidgeon less mid magic in the portrayal, BUT it is made up for with the rest of the spectrum. I guess one cannot have it all! One of the things that does bother me most with other systems I have heard that use subs and minis, is any "hole" in the transition....to me that always is VERY noticeable. Luckily, after much experimentation that isn't an issue for me with the T5.

[Phelonious Ponk]

I want one.

Tim

[mep]

Davey, I note with interest that the T5 xover has a fixed 12db slope, a choice that I disregarded in favor of the JL's steeper 24 db option, in large part influenced by Jonathan Valins review of the Torus subs which he mated to the Mini using a 24db slope at 33-37hz. I experimented with the 12 db slope and with careful adjustments to cover frequency and volume levels, I have to admit that it was foolish of me to have concluded that the 24 db slope would be the best choice based on a review of a different sub based system in a different room. With the steeper slope I sometimes noticed that, with certain material, there was a subtle but noticeable "hole" between the subs and the monitors, which gap the 12 db slope seems to patch to create a more seamless transition. But as I said, I'm still experimenting and I have to say playing around with all the xover options has been a very educational experience on the fine balancing act required to create a satisfactory and seamless transition from monitors to subs.

If you have a "hole" with a 24dB slope, doesn't that tell you that your crossing over the sub too low for your main speakers? Lots of monitors have no real output below 60 Hz and if you are trying to set the sub crossover to below 40 Hz with a 24 dB crossover, it will be 24 dB down at one octave above your crossover point.

[FrantzM]

If you have a "hole" with a 24dB slope, doesn't that tell you that your crossing over the sub too low for your main speakers? Lots of monitors have no real output below 60 Hz and if you are trying to set the sub crossover to below 40 Hz with a 24 dB crossover, it will be 24 dB down at one octave above your crossover point.

Hi

I would recommend two subs.. It affords you a smoother FR, paradoxically the smaller the room the better the results with two-subs. I have countless of times posted about my preference for multi-subs. It is not a matter of only output but of smoothness of response. Good bass is firstly about getting a smooth response.
Second the crossover point frequency is as important too and so is the phase control... It is very important to play with al these parameters: Position of subs with respect to mains, Crossover frequency, High and low pass point i the subs have these and the phase control... all play a role in the final sound. When the subs are properly dialed in even the highs become clearer ...Often the discontinuity the impression of "hole" the "slow" bass phenomenon a misnomer by the way is caused by improper subwoofer settings (or insufficient flexibility of subwoofers controls) .. Too low a crossover point with a monitor that does NOT truly plumbs the low freq may create this "hole"
Doing all this by ear is do-able but to have a better starting point I would recommend to use a software to measure your FR in the low. The learning curve is frankly rather steep but it is worth it. Room EQ Wizard REW for shortm is a free, feature-laden software that would help you in this department .. Total cost if you add a decent calibrated measurement microphone and Sound card would run you less than $200. If you're press hard will cost you less than $150: Card about $75 + Microphone $75 or so, REW is free.

[dafos]

To everyone, thanks for the feedback!

[Robh3606]

If you are using a L/R 24dB crossover all you have to do to avoid a hole is use the spec -6dB point of your monitors as the crossover point. If you do that it will sum properly providing your -6dB point doesn't coincide with any room modes

Rob

[rbbert]

Did I miss the part of this thread where the choice of one T5 (only) was discussed? With the rest of the OP's system, I would have thought at least a couple of T7's or one R328 or R528 would have more consistent?

[rblnr]

I've used a REL 505 for years with ATC 20-2 actives -- makes for a really nice system.. I run it using a TacT mini doing the crossover, which I then tweaked the XO curve based on some measurements using XTZ. I always find the phase to be the most 'underrated' parameter to nail -- your seat can easily be in a null, but a slight phase change (or position change of the sub) will mitigate it.

[DaveyF]

Did I miss the part of this thread where the choice of one T5 (only) was discussed? With the rest of the OP's system, I would have thought at least a couple of T7's or one R328 or R528 would have more consistent?

Rob, I considered the T7, but in my VERY small room, it was possible that this sub would overdrive the room too easily. One can turn down the volume, but I think by doing that too much, you risk throwing out the baby with the bathwater. ( Strange old saying, did anyone actually do that in the old days, LOL)