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Red Spade Audio

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About Red Spade Audio

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    Melbourne
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    Australia
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    Paul

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  1. Red Spade Audio

    Polymax Absorb XHD 100mm batts

    Coming along nicely! You can create gifs online using GIPHY or an online search will show up freeware gif makers. This one is quick and easy: https://giphy.com/create/gifmaker
  2. Red Spade Audio

    4” full range speakers and IKEA bowls

    Ikea fruit bowls! Very clever way to put together a DIY project!
  3. Red Spade Audio

    Polymax Absorb XHD 100mm batts

    It's a bit easier to see with a gif. Anthony's waterfalls: Thanks for sharing the waterfalls. What kind of subjective difference did you notice? When using lower density bass traps with a low GFR, you can improve results by making them thicker. However, when you are using products like Polymax, greater thickness is not always more beneficial. There are trade offs involved between bass and low midrange absorption. The theory doesn't contradict practice. The theory is built into the models which predict that practical resistive bass traps can be made, using dimensions that are much smaller than ideal, with measurable and audible improvements below 100 Hz.
  4. Red Spade Audio

    DSP options

    Thanks for the mention Snoopy! Nanodigi from MiniDSP is one to consider: https://www.minidsp.com/products/minidsp-in-a-box/nanodigi-2x8-b You can insert between source and DAC and apply manual EQ. This requires measuring the response and manually setting up parametric filters, so you would need at the least a USB measurement mic + free software REW and a learning curve. Speaker placement can also be a factor, especially in spaces like these where it's a challenging compromise. If the muddiness is related to peaks in the bass and low mid region then EQ will do a reasonable job of taming the issue. At higher volumes the sensitivity of our ears adjusts, meaning the problem becomes more severe.
  5. Red Spade Audio

    Fasting, anybody done it?

    Great topic! I'm doing my own "DIY diet." The problem with most diets is that they are very restrictive and are too easy to fail. When you design your own diet, it's inherently flexible and it's also a lifelong process of learning. Daily fasting means I can function without food for much longer. The basic idea is to track what you are doing, notice what is working and keep adjusting until you get the result you want. I've lost 12kg and I'm moving steadily towards my goal. Here's a few things I've found really helpful: 1. Start each meal with veggies only on your plate first, then add meat and the things you most want to eat that are "healthy enough." Finish off with as much fruit as you need to be full 2. Track your weight, exercise and calories, making adjustments until you steadily lose weight - the My Fitness Pal app is great 3. Figure out the foods that satisfy within your calorie targets 4. Don't go too low on calories because your metabolism will go down and you are married to the calories you choose with no option for divorce
  6. Red Spade Audio

    Magico Q-Sub anyone?

    I'd suggest their response means one of two things: 1. The person answering doesn't know 2. They don't think it's in their best interest to answer directly It's usually quite easy to spot the difference between a DIYer fishing for information and a customer working through the questions they need answered before they are ready to buy.
  7. Red Spade Audio

    Speaker build idea.

    Quite often you can't make sense out of what you experience fully, without considering what the room is doing. You can have a speaker that extends to 20 Hz in room and yet feel that bass is lacking impact and depth. For bass to have impact, extension is the first requirement but you also need the right balance. For most people to feel the bass has impact, the SPL level where they listen needs to be quite a bit more than everything else. Quite often this impact comes from room modes that might be giving you extra punch in the midbass. This comes at a cost however, because you will also likely have parts of the bass missing and perhaps also poor decay. So it might sound boomy. Sometimes, if you get a lucky combination, it just might sound balanced. A speaker with higher sensitivity just might give you less bass impact in the bass, all else being equal. If you are trading bass extension for sensitivity, you can potentially miss out on the extension you need to deliver the impact you are seeking. On the other hand, if you know by testing what the room is actually doing, you can actually design to work with it.
  8. Red Spade Audio

    Magico Q-Sub anyone?

    If there is a link pointed to our website that shouldn't, would you mind letting me know? If you want the Rythmik finished subs, Audio Salon is the only option I'm aware of. If you buy from overseas then keep in mind there are implications regarding warranty and support. It's worth keeping in mind that plate amps have a shorter expected lifespan than just about any hifi amp you are likely to have in your rack. They often fail a few years outside of their warranty. Or if they fail later, often you can't get a replacement amp. Rythmik stick to standard cutout sizes for their amps, which comes in very handy if you ever need to replace an amp. We manufacture the cabinets here in Australia but they aren't built by me personally, with only rare exceptions. We offer both kits (amp + driver only) and the option of made to order subs, which could be either something fairly standard or something "very custom." If you want the best price on Rythmik finished subs, you will most likely get it from Audio Salon.
  9. 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.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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.
  15. Red Spade Audio

    Ported or not

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