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Red Spade Audio

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About Red Spade Audio

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    Melbourne
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    Paul

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  1. Red Spade Audio

    Magico Q-Sub anyone?

    It's always a good idea to take max SPL specs with a grain of salt. They are notoriously optimistic. It's not a question of who knows more. It's a question of being clear on exactly what is being claimed. Magico isn't claiming magic. They are doing what almost everyone does in using an optimistic and vague specification. So I wouldn't single them out for criticism.
  2. Red Spade Audio

    Magico Q-Sub anyone?

    They would have to be estimating room gain to get that figure. If we look at what a 2x18" 4kW sub can achieve at 20 Hz, it's around 120 dB outdoors. With 4kW into both drivers, 80mm excursion (peak to peak) is required. Throw in 16 dB of estimated room gain and you get 136 dB. In an average real room you add +/- 15 dB on due to room modes. In reality a sub will always measure at a lower max SPL than modelled due to mechanical and thermal effects. Further, it's being generous to assume the driver can handle 80mm excursion. It requires a considerably large surround, which the driver in the photo does not have. I'd suspect it probably would do 1% THD under certain conditions eg. above 40 Hz at 90 dB. If Magico had really figured out how to achieve 136 dB outdoors at 1m at 20 Hz with only 1% THD, I'd expect to see several patents and ground breaking innovation. To put this into perspective, a pair of horn loaded 18" drivers would not achieve that spec either.
  3. Red Spade Audio

    Acoustic transparent screen negatives

    The problem with calling it "degraded sound quality" is that it sounds like an insurmountable problem. Based on how you've rated the pros and cons, an AT screen looks like a fairly poor choice with little to justify the cost and downsides. But let's take another look at it ... The sound quality issue is that it will change the frequency response, typically with more treble reduction and this change might also vary with frequency, meaning that it will affect different speakers to varying amounts. The good news is that you can correct it with EQ, which is actually a good idea to do in any serious HT system, whether you have an AT screen or not. But I'd suggest you are downplaying the benefits. Matching the screen and dialogue is only part of it. As Peter mentioned, it opens up the space behind the screen and you can use it in many beneficial ways. You might create a false wall for a nice neat front view, all your equipment up the front for easy access, but hidden in cabinets. You might create a very large bass trap across the entire front wall. You might create a baffle wall, with your speakers flush with the wall but also hidden. You can also hide very big and ugly speakers behind the screen and still end up with a cool looking room. The benefits of doing all this are quite extensive - screen/dialogue matched, financial, aesthetics, speaker performance and acoustics. In a system that is also used for 2 channel music, having speakers close to the wall reduces sound stage depth. In a suitably sized dedicated HT room, I'd argue that the benefits far outweigh the downsides.
  4. Red Spade Audio

    Push Pull Subwoofer Build?

    You may be happy with that but there are a few things to bear in mind. First, quieter fans move less air, meaning they are also less effective at cooling - reliability is compromised. It's not an issue for most people. Second, even if you get a fancy super quiet fan and spend a bit more, the noise isn't just dictated by the fan itself but also by the airflow within the amp itself. In other words, there is a limit to how quiet you can get due to the air moving through the grille and heatsink. It means you might not get it as quiet as you hope. You can't really isolate those two factors, because both of them together along with other factors are needed to determine extension, SPL and sensitivity. I'd put it this way. Displacement (cone piston area x maximum excursion) determines SPL. This is true for all frequencies, however for a given SPL, the displacement increases with decreasing frequency. To get that extra displacement in the bass, you can increase excursion or piston area. More piston area gives you higher sensitivity. More excursion gives you more SPL at the cost of needing more power and compromising linearity. For a given piston area, the sensitivity of the driver can be changed based on the intended bandwidth. You can maximise sensitivity with a strong motor and low moving mass. You might get an 8" midrange that can give you 100 dB sensitivity but that will only apply above say 500 Hz. On the other hand, a subwoofer will generally have sensitivity in the range of 83 - 90 dB. Hoffman's iron law is a simple concept to keep in mind. It has three parameters - box volume, sensitivity and bass extension. You can choose only two and the third becomes a given. When you have chosen the parameters you have in mind, you can then choose the driver and enclosure design to suit.
  5. Red Spade Audio

    Push Pull Subwoofer Build?

    Europower amps are good workhorses but especially on EP4000 the fan is REALLY loud! Even with a fan mod, if willing to void warranty, all fans are still a bit noisy to be in the room. What's the plan? Putting them in a garage and running some cable is a good way to go. If you want a small box, you picked the right version (HO), apparently by accident. These are car audio versions - don't be put off by that. It mostly means they are designed for small boxes. The advantage with dual driver subs is that you can reduce vibration of the enclosure by having them on opposite faces of the box - one on front, the other on the back. You can use this to either create a really inert box, or simplify bracing. 2x15 is likely to deliver more midbass headroom. Much of the action in films lies here. A single 18 is likely with more excursion to deliver more deep bass output and often budget will favour this option. Impedance is also a factor, depending on what you are aiming for. With Europower amps, you want to end up with 4 ohms into each channel. 8 is limiting the power, 2 ohms is pushing your luck. Expectations. I find that for home theatre, people expect more output and are more likely to use it. Films are mixed for large commercial systems with more dynamic range. In a music system, people are often more critical of quality. Partly because a movie engages our attention differently.
  6. Red Spade Audio

    Professional Room treatment Melbourne

    Actually we do offer a full service including room analysis, treatment advice, acoustic design & documentation, supply of DIY/finished/custom products and installation. In terms of time frame, we normally can book in a session within 1 - 2 weeks with advice onsite.
  7. Red Spade Audio

    Ported or not

    Correct - any speaker will suffer from inconsistent bass in different positions around the room.
  8. Red Spade Audio

    Ported or not

    Ported speakers can go closer to the wall than many people think. You can often go closer than the general rule of thumb (no closer than the port diameter) without any obvious penalty. The real damage is done to the sound stage. More often than not, a little toe in will offer an improvement in several aspects whilst also as a bonus, giving you an adequate port clearance. This issue you mention is very common and generally not well served by switching to other alignments. There two basic solutions: 1. Demolish the whole house and listen outdoors. Rooms are evil, get rid of them. (Look no further than StereoNET for the most helpful advice!) 2. Place multiple subwoofers in positions that have been tested as suitable to deliver more consistent bass across more of your room. One word of caution. I never suggest just going out and buying a bunch of subs. The idea is to first work out that you will get the intended benefit. Testing required.
  9. Red Spade Audio

    Grills on or off

    There's two ways I could answer this. Could you hear the difference in a quick AB comparison? Would you notice the difference in a longer listening session, when you weren't critically comparing but just listening to music? The short answer is yes and probably not. Keeping in mind it will be different for each speaker. You have a dome tweeter with wide dispersion and large cabinet edge treatment to minimise diffraction at the cabinet edges. A grille adds an edge which doesn't behave as well. More than likely the designer had grilles off when designing the crossover - you don't go to all that trouble of those kinds of edge treatments and then throw it away with a grille frame! If it were a reduction in treble that is constant - even just 1 db consistent loss would cause a subjective difference you would notice even in the longer listening session. Discerning ears will pick it up as reduced detail. However, with grilles as you can see, it's not a consistent impact but a series of dips. That's a bit harder to pick. At the same time, your head can tend to get in the way and this alone can have a bigger effect than the actual objective difference. I was always a grilles off listener because intuitively it seemed like the thing to do.
  10. Red Spade Audio

    Grills on or off

    For me it's always off. Grilles do have an impact on the sound and it shows up clearly in measurements. Here is an example. These measurements were taken from a 3 way speaker with an air motion tweeter, dome mid and 8" cone woofer. The grille was actually better designed than most to avoid excessive diffraction. Tweeter (lighter colour is with the grille on) Midrange (lighter colour is with the grille on) Woofer (lighter colour is with the grille on) These are raw responses with no crossover in place. The difference is enough that it would result in a different crossover, depending in whether the design is based on having the grille on or off.
  11. Red Spade Audio

    B&W DB1D vs REL Subwoofer

    Both REL and B&W subs have also been independently tested as well, although I've not seen the units you are considering tested. Here is one collection of tests: https://www.hometheatershack.com/forums/subwoofer-tests-archived/6015-index-subwoofer-tests-manufacturer-model.html In the Rythmik range, there are no top models. The larger models simply have more output. There are a few SE models that have a piano gloss black sprayed finish. I should also point out that we don't carry the finished Rythmik audio range. We supply kits or premium custom manufactured subs. A few comments about the 3 subs you are considering. The B&W is less than half the size of the large REL but close in weight. This would suggest the B&W most likely has a more inert cabinet. Further, the driver mounting on front and rear offers vibration cancellation. Considering these together, the B&W would be superior in this regard. Given around 1kw amps in both, the performance difference will be mostly related to size and alignment. The B&W is sealed and half the size. The REL has a passive radiator alignment, which means it performs more like a ported sub with the potential to tune it lower relative to its size. If we assume similar driver excursion capability, then you can expect similar capability for music (above 40 Hz primarily) but considerably more output from the REL for home theatre (below 40 Hz). I'd anticipate the REL would probably have 6 dB more output at 20 Hz and this advantage would diminish to zero around 40 Hz. This is a fairly quick rule of thumb that applies to the same power and excursion with a ported sub being twice the size. So at 20 Hz, the REL behaves like two of the B&W but for music this generally doesn't apply. If you are choosing between these three, I'd rule out the third option as a bit limiting. Out of the remaining two I'd probably nudge you more towards the B&W, as I suspect it offers more of what you actually want. I don't think the extra size of the REL is justified here. Overall I think it's a better fit in terms of what you've said so far.
  12. Red Spade Audio

    B&W DB1D vs REL Subwoofer

    The idea doesn't translate very well to subwoofers. You can often identify good speakers in a bad room. With subs it's different. You can have a bad sub in a good room and a good sub in a bad room - quite often you won't know which you are hearing, because we typically can't discern the difference just by listening. Retail demos will often not show the kind of acoustic problems you will have at home. We also offer a remote service. If you want to minimise the visual impact of the sub/s on your living room, a few things to consider. Firstly, from a performance point of view, many audiophile music systems don't benefit significantly from more than one sub. The benefit is not automatic and quite often adding more subs will create some issues. Secondly, in some rooms, two smaller subs can outperform a single much larger sub, minimising visual impact and giving you a great result. This might be the case where every possible position has a big dip in the middle of the bass - this is where a second sub in the right position can solve the problem. This requires testing. If you're not wanting to do any testing, I'd suggest sticking with just one sub. Otherwise, step two might be a step backwards. An example might help. Black shows an existing sub in a fairly typical position. There is a big peak at 26 Hz which makes a fairly small sub perform quite impressively on LFE effects. It's about 15 dB above the average sub level. On the other hand, notice the big dip in the midbass from around 30 - 50 Hz? This was making the bass a bit underwhelming, especially on movies where much of the action is happening. With just this one sub, you could bring down the peaks and you'd have to leave the dips. You'd get a much more balanced bass as a result. However, this example really does call for a second sub. The red line shows the same sub in a different position. You can see that this second position doesn't suffer from any of the same dips. The final result after calibration is one that would not have been possible with any single sub. So you've seen a good example of how you might benefit from a second sub (with optimal positions) but now let's look at a different room in which one sub is just fine. Three different positions tested. This room has a few positions like the black, which is near ideal for a sub without any EQ. There are no significant dips and where a position like this is feasible, you just need a little EQ to adjust the balance - you can see the upper bass has a bit too much emphasis. Otherwise, there is no real performance reason for more than one. Armed with this knowledge, you might make a different sub choice than going in blind. You can also see, the other positions are not so good. The red position has no real impact below 50 Hz - a sub there would sound anemic. The green position is even worse. It has about 18 dB less than the ideal position. This means you would need 8 subs in the green position to do the same job as one in the right place, in that particular room. If you were to walk into these two rooms, you would not be able to guess which is which. However, the strategy that makes sense for these two rooms is entirely different. The best answer is very room and system specific.
  13. Red Spade Audio

    Atmos setup advice

    SB1000 is a pretty good suggestion for a small room on a budget. One problem you might have with dialogue is that movies are mixed with commercial cinemas in mind. In other words, they have more dynamic range than you can often use at home, which means if you set the volume to avoid dynamic scenes becoming loud, the normal dialogue at talking level is too quiet. In some cases, it's a simple matter of volume. The simplest solution is choosing an AVR with a night listening mode, which compresses the dynamic range, so that dialogue is louder without the louder parts of the movie becoming too loud. Other causes could be things like speaker placement and room acoustics although the latter is more likely to give you problems in a much larger room that is very bright. In a small room of those dimensions, you will tend to face bass issues. Any sub, no matter how good, is likely to sound boomy in the mid to upper bass and it can get especially bad when listening up against the rear wall. EQ is essential.
  14. Red Spade Audio

    Toeing in speakers.

    Not surprised
  15. Red Spade Audio

    Sub in middle of room not corner

    After over a decade of testing, one clear lesson is that no single position best fits all. Without testing the acoustic response of all the positions that are feasible, it's just not possible to give you a real answer.
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