You answered some of mine. Thanks for the great information.
Bookshelf Speakers Sitting On Dual Subs?
I have a couple excellent subs - Elac Adante 3070 - which have pretty effective DSP. I'm thinking of buying the Dutch&Dutch 8c (also DSP). The Elacs are rock solid. I'm thinking about placing the 8c on IsoAcoustic stands on top of the Elacs so the 8c is even with the front of the Elacs and separated by the Iso stands: running the DSP for the subs and then the 8c. Any real drawbacks to this set-up?
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There’s been a good bit of mention around the 8c in this thread so I’ll try to chime in a bit. The 8c does have dual 8" subs on the rear of the cabinet. They do perform best when boundary loading to your front wall or similar surface (I’ve used glass on more than a few occasions). This works best from 4-20". The subs operate from 100hz down. The anechoic response is flat to 35hz, but real-world, in-room response is typically flat to 20hz or lower. At Pacific Audiofest, we were easily flat to 15hz (not -3db@15). The 8c does have sub outputs. These are full-range "unmanaged" outputs. That is to say that they do respond to volume control but do not have additional filters (crossover, eq, etc.). In terms of stacking subs, the main benefit of adding subs to the 8c is not additional output at the main position. The 8c is already full range and most any bass issues will be room related. More subs placed in the same position will only exacerbate modal issues. If you have 8Cs and bass problems, look at distributing the bass to resolve room modes, not augment the 8c output. The 8c does have DSP, but we consider it an acoustic product first, with DSP in place to augment what it’s doing passively. We use DSP to phase align the front facing drivers to the subs, which have a delayed response depending on how close or far they’ve been placed to the front wall. Additionally, the 8c is fully REW integrated, which we use to apply EQ to frequencies below a room’s Schroeder response (typically in the 20-200hz region). Lastly, being an active speaker, dsp is used for our crossovers, gain controls, etc. Everything else is passive. The cardioid mid range from 100-1250hz is a purely passive design. Our tweeter waveguide allows us to highpass our tweeter at 1250hz to prevent the 8" mid from beaming, gives us a near mirror image on/off axis response. Between the mid and tweeter, we are constant directivity from 100hz up. The rear firing subs, when boundary loading get +6db of free lunch below 100hz, and don’t suffer the typical destructive cancelation of a bass/sub that’s been pulled out into a room. The net result is extremely taut low bass that doesn't strain the bass drivers or electronics. When we apply EQ, we typically remove bass, not add it. In any event, I hope that this has at least answered a few questions about how the 8c works. |
+1 fuzz erik bayl jjss onhy... The Elac DSP might allow you to roll the subs frequency response off beginning in the low 40Hz, continue until your down by -6dB in the low 30Hz. The Elac should now act like a -6dB sub-bass speaker. By lowering the Sub-bass speakers volume reduces their affect on exciting a rooms standing wave. People often stack six of them next to their speakers and appear to be quite satisfied. If you don’t know what your missing, well... Good luck with it. _________________________________________________________ Some equate a lack of cabinet vibration an indication of low distortion. The Elac video of the nickel standing on edge while measuring 7.3 - 28.2 dB of (?) distortion is telling. With some subs .5dB is an average. I’m missing something? |
This probably is an overly bold assumption. If the sub is not in an optimal location and / or its performance is not optimized by its own DSP, relying on an external DSP in attempt to optimizing both main and sub simultaneously would possibly lead to a less desirable setting. I thought a more logical stepwise approach would be to use the sub's DSP to optimze the sub performance first and then use the D&D DSP to optimize both. But only you know the best. This is a quite interesting, educational experiment and please update us on the results. |
Scaling back from dedicated room with audiophile rig into a new home with a great room serving multiple uses. The 8c will sit nicely atop the 3070s about a foot from the brick wall in a room which is open to the second floor, the foyer and the kitchen, and rises from about 8’ on one side to about 20’ on the other. The system is going along a rising 8’-20’ wall, firing across a very asymmetric room. This is a compromise system until a dedicated room appears again. DSP in the subs and the 8c will be this room's best friend. The original question was about the stacking aspect of the 8c on the sub really. I believe that D&Ds DSP correction will even take care of the sub’s behavior when the signal is run through the monitors (even though the 3070s have their own optional DSP). The goal is more bottom octave, and fuller dynamics through the space. I have no doubt that the DSP will do its job, my interest was ore concerning the stacking aspect and, honestly, @normb nailed the landing quite succinctly, I’ll bet. |
What is the end goal you are trying to achieve? Louder over all playback levels, more thump? The 8C’s appear to have a sub out, is it full range or do they have low and high pass filter capabilities? The drivers in the 3070’s appear to be on angled baffles, are you using them in a side firing configuration or a front and back configuration? Are the 3070’s currently in the room now and if yes are you having any issues? The first potential issue that jumps out to me could be a phase issue. A lot of drivers facing different directions, specially if the 8C’s are run full range. Potentially a lot of different paths for the sound waves from different sources to take on their journey to your listening position could make for some muddy bass. The another possible issue if the 8C’s are full range is that your subs may not have much to do. According to the 8C’s spec’s they are good down to 30 Hz, not much in recorded music gets that low, not too mention lower. |
So it seems desirable to place D&D close to the front wall. Now the issue you have to cope with is whether which location is optimal for Elac sub. if you want to stack them up ... |
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When I think of low frequency vibration damping, I am always thinking high mass (example: thick steel/granite/concrete plate) sandwitched between think damping (rubber has great internal damping) matts (from high density machine/work matts to softer rubber. May use 'spike' technology to further pinpoint vibration energy for easy killing.
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Rule of thumb selling audio on average ,you want the main tweeter level just about at ear level , that being said doesnot always apply i bought a like new pair of Dynaudio , 3.5 fooor standers and the tweeter is on the bottom, this iso tech,isotar tweeters have great expansion I would buy the iso acoustics pucks to put under the speakers for vibration ,this way too it would add 2 inches to the height and should work out well , just keep in mind toe in as needed if sitting in the center. |
It seems to work for some people.
https://www.audiogon.com/listings/lisb42g0-goldmund-samadhi-full-range |
I am not sure this is true. If you think about it, all towers, including the ultra expensive Wilsons, the Kef Blade etc have the woofers together with the rest of the drivers (albeit sometimes in separate chambers). In fact, the 8c themselves have built in subs in the same cabinets. In these systems, it’s almost impossible to isolate totally the low frequency drivers vibration from the mid-high drivers.
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well then, it's settled... that's the end of discussion then, right? oh wait, he sells megabuck speakers with giant sub bass modules mounted just below the mains... doh!!!! 🤣😁 important in life to know when someone telling you something is to help you, or... |
I have learned NOT to place dual subs in a stereo setup next to or under the mains EVER. It will result in overly booming bass specially in the rear of the room. Once placed on different walls at different positions, the extra booming was gone and they sounded THAT much better. You can see the exact placement that worked best for me under my handle in my house of stereo system. I learned that from a valuable member here. By the speakers was a losing battle. |
I had some Axiom M22TI bookshelf speakers I used in this manner and didn’t feel it was a negative. The dual subs help cancel standing waves, and as long as the tweeter height is satisfactory let your ears be the judge. I had used some Audioengine stands for my setup as they provided some tilt. I am running dual subs for my current setup but they live behind the primary speakers now, not under. |
8cs do have the rear 8" drivers which are great, but this is for a bigger room and to fill in lower end. The 8cs apparently do rock, but this is a large and oddly shaped room. Note to above posters pointing out sub placement issues: DSP, DSP, DSP. I am well versed in manual sub placement by ear. DSP is not perfect, but it's pretty damn good these days for sub-optimal room situations. As for vibration issues: essentially zero - the 3070s are rock solid. With isoacoustics stands on top with the 8cs on top of those, I suspect zero vibration from subs will get to the 8cs. |
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Vibration is a killer of high sound quality. Subwoofers are vibration devices. So if you want good sound quality, no. You want very sturdy, heavy (typically filled with steel shot) speaker stands to place the tweeters at the exact listening level. Isolation devices improve sound from already solid footing. As also pointed out you want to optimize both speaker placement and subwoofer placement and there is nearly no chance those will be in the same location. |