Thanks anyways! At REL we make powered subwoofer speakers for stereo & home theater systems. Sharp versus Gradual: The second major choice we make in designing a REL crossover is choosing the primary filter set. Poorly designed crossover (left pic); a high quality crossover (right pic) The crossover (above left pic) is from a two-way bookshelf speaker system we have previously reviewed . I took some quick readings from my REL Quake using an EMM-6 mike placed at the edge of the box (driver fires downward): The blue graph shows the frequency response with the low-pass filter disabled, red with roll-off set to roughly 40 Hz. Thanks for the effort I really appreciate it! I don't see why it would use a different filter, though. You can use your preamp crossover with the REL subwoofer- just set the REL crossover to full max (i think it's 120 Hz) and let the preamp crossover do the work. (slope -1) is independent of the molecular weight 10-4 10-3 10-2 10-1 10 0 10 1 10 2 10 3 10 4 10 5 10 2 10 3 10 4 10 5 10 6 10 7 100000 10 5 10 6 Slope 3.08 +/- 0.39 Zero Shear Viscosity Zero Shear Viscosity η o [Pa s] Molecilar weight M w [Daltons] Viscosity η * [Pa s] Frequency ω a T [rad/s] SBR M w [g/mol] 130 000 230 000 320 000 430 000 So, does this mean we have hoodwinked hundreds of thousands of customers? The speaker system employs a stiff cone driver which has no crossover circuit (namely a LPF) to limit its bandwidth to reduce its audible break up modes at higher frequencies. High Level Input Versus Low Level: Experienced REL devotees might be surprised to learn that even though we are famous for our High Level Input, which connects to the speaker terminals of the main stereo (or dual mono) amplifier(s), you are really using the filters built into our Low Level Circuit. These can take an analogue signal, do A/D, then do the DSP and then D/A to the main speakers and subwoofers. If your system is using one of these, and you’re not sure how to do it yourself- it’s probably best to leave it alone. It's easy. Passive crossovers giving acoustic slopes higher than fourth-order are not common because of cost and complexity. It will send the controlled signal to the subwoofer and blend with your main speakers at the intended frequency and slope. All subwoofers use 1 of 2 types of filters; they either choose to limit and roll off just the high frequencies, allowing the bass to emerge from the sub but permitting the speaker to run full range. That their work most closely approximates the way YOUR ears, brain and life experiences inform you of the sound of music live. But also know that we remain hungry, always looking for that last little bit, the next performance edge that no one else has considered that will take us that much closer to the real life experience of great music and theater sound. Developed by our engineers specifically for use with REL subwoofers to maximize the information available in the high-level connection. If you could come back in a million years you would see that nature had reduced the sharp filter–the sharp-edged aggressive crossover slope of the cliffs–to resemble their gentler-sloped sandy beachy counterparts. It is often used as a starting point when choosing a crossover type. Cutoff slopes of at least 12 dB per octave are usually chosen because of limitations in the frequency range that drivers can faithfully reproduce. For example, a second-order low-pass combined with a third-order high-pass filter. Rel wants it to be used as a "sub-bass" system that takes the L&R main speaker input (preferably at speaker level) along with the LFE input. I know I am being dense but I need to understand this, I get the concept and understanding of crossovers completely, what does the slope bring/not bring? Free shipping on all orders. There's a switch to enable/disable it and a knob to set the cutoff frequency. Either way, we have you covered. Guess I'll have to rig up a test for that too later. Our award-winning home theater subwoofers with wireless capabilities elevate any system. The graph above clearly shows a difference. It’s true. By "it," do you mean the high (speaker) level input? Lounge: Anthem MRX 720, config 5.1.4, Emotiva XPA5 Gen 2 & BasX A 500 power amps, Sony 65XE9305, Sky Q 2Tb, Sony UBP X800, XTZ Cinema Series M6 LCR, S5 Surrounds, S2 Rear Heights, KK QFH Front Heights, Rythmik FV15HP . so I be getting set up with REW soon. For more information on this topic, we recommend reading our article: Filter & Crossover Types for Loudspeakers. But it also means that our Low Level circuits enjoy exactly the same special attention to crossing over, and do just the same job of blending and making naturally better full range sound than any other subwoofer design we know of. Due to a Covid-19 exposure in our warehouse we are experiencing 5 day shipping delays. We choose to reveal the best and leave the rest. if you are using a "high level" connection method (DB/Octave)? How every filter we have ever developed passes through an endless series of listening assessments evolved over decades of careful designs and that only the most natural approach to this is fit to make it into your REL. Both using the low-level input. It is this ability to get down beneath the main speaker and blend seamlessly that is a big part of REL’s magic. No, but I have a UMIK1 on the way now (being shipped all the way from Hong Kong!) This means that the audio processing can be changed much more easily, without any hardware changes. We make it all work seamlessly by designing filters that can extend all the way down to 20 Hz on almost every model, so that you can roll off the higher frequencies lower down and allow the REL to mate perfectly BELOW the functional limit of the main speakers. We just want to help you get at the more complete, totality of that experience it. Audiophiles may prefer the much more expensive and very clever Illusonic devices. Also compatible with G1 Mark II. An extreme-slope crossover at 500 Hz has been designed for the Klipsch Jubilee. Setting up the high level input would take me a little longer, and I really should be doing other things right now. I have looked in vain for this info on their site and here/Google... Hey MQA, if it is not all $voodoo$, show us the math! Plug in and play, zero-compression wireless system for Serie T/i that eliminates the need for costly and restrictive cables. Without diving too far down the engineering rabbit hole of slopes and knee points, nature prefers gentle, progressive overlap to sharp harder edged transitions. Official online store. … Go visit a beach sometime, frequently beaches have cliffs standing adjacent to them; the sharp filter set if you will. According to the manual, the crossover is always enabled for the high-level input, optional for the low level one. But then, there is that last bit, the tricky bits that elevate merely very good products into the realm of the truly special. Altering this would and does—we know because we’ve developed and listened to virtually every topology of filter set over the past 30 years–destroy the delicate balance of design that talented main speaker designer made to achieve the experience you already love. Ah  - so your low pass filter is in your pre-amp/processor. crenca, T/7i. This diagram is courtesy of Williamson-labs.com. I assume you are using REL's "high level" connection and thus relying on the high level crossover? We use the former, most choose the latter. Of course not, it means there is no point to crossing over in the High Level portion of the circuit when it will need to have its output reduced so that our power amplifiers can see a signal appropriate to their gain structure. The diagram pictured here shows basic schematics of each filter type along with a generic theoretical slope response. Most of today’s systems have an EQ feature that will set up the proper crossover automatically based on the specifications of your speakers. I've been meaning to do this measurement for some time, just haven't got around to it until now. About 90% of it is good, sound, common sense engineering built on a foundation stretching back some 25 years. Articles is our blog where we share insights, information and opinions on subwoofers, hi-fi systems and the joy of sound. Sign up and stay connected for exclusive deals. For example, making the crossover slope steeper would require additional analog circuitry - not easy once a unit is in the field. The brains of a great subwoofer lie in its filter bank; the crossover circuits that define the behavior of its performance.