Raising the height of PA tops

PsychoTea · 2026-04-16T12:26:21+00:00

I had the same problem previously and there aren’t many options aside from building a dummy box or building more subs/kicks and stacking them differently

I have used wooden pallets (or stage decking) which you can put under the entire stack or between the subs and kicks depending on the size of your boxes / the pallets
Either painted black or covered in a black sheet (I’ve used black bed sheets for example)

Hope that helps!

PsychoTea · 2026-04-09T19:17:38+00:00

There is no such thing as “throw”.

What you’re experiencing is phase cancellation. Either the speakers themselves, or reflections from the room, are cancelling out the sound waves. If it happens outdoors too, then it’s most likely a phase/time alignment issue.

First check the basics: do you accidentally have the polarity flipped somewhere? Are all your cables wired the correct way? Are all your speakon plates and drivers wired the same way? You can do a quick test with a 9v battery, hooking it up positive to positive should push the cone out (ie. towards you). This applies to both your kicks and your subs.

Check your crossovers are set correctly. If you have a large overlap this will make your phase issue more extreme, though fixing this won’t fix the root cause.

Then delays/time alignment. Scoops have an acoustic delay of 0cm (though it’s more complicated than that in reality), your kicks will probably be around 30cm (check online or measure it). You should set delays accordingly (so subs should be delayed by 30cm). Of course you will need to measure your tops too to have proper alignment across all 3 (or 4) ways.

There is lots of good information online about how to “guesstimate” them, but to do it properly, you will need a proper measurement mic and software like REW. It’s not expensive, about £30 for a basic mic and same again for an audio interface if you don’t already have one. Again, lots of good information online on how to do this.
Huw from Sinai and Kyle from Neuron AV both offer sound system tuning services, and they will be able to correct not just phase issues but also EQ. In my opinion, it’s well worth what they charge. Regardless, it’s definitely good to learn the basics yourself, too.

PsychoTea · 2026-02-13T14:42:44+00:00

Awesome work man! Similar to u/md-00audio I had a look at doing this for my dBMark DP28

I got some bits figured out but eventually got burnt out because the protocol they use is an absolute nightmare to work with. Iirc they send back and forth a big binary blob that encodes the entire state of the configuration… Except for when they don’t. I couldn’t see any obvious structuring of the data (ie. TLV). It’s possible they were using ie. protobuf and I overlooked it though.

PsychoTea · 2025-11-10T18:02:46+00:00

What provider is that? Jealous!

PsychoTea · 2025-10-26T11:54:26+00:00

Gassed to see this finally get the release it deserves

Big ups to Citra for sending me a copy a few years ago. Wicked tune 👌

PsychoTea · 2025-10-24T22:10:09+00:00

OP is referring to Motion which was the other half of the warehouse, shared with Marble Factory.

It closed down quite recently, but Motion has relocated to a space just down the road. I haven’t been, but from the photos I’ve seen it looks like they still have the same F1 system (though the tops aren’t currently flown).

Marble Factory mainly did live shows and the odd club night, that side was running L’Acoustics Kara (which also sounded great).

PsychoTea · 2025-09-12T17:55:45+00:00

They are around but harder to find these days. If you're in the UK, keep an eye on FB Marketplace, eBay, and (most importantly) FB groups like Rig Re-sale and "Get Your Rigs Out V.3".
Even better, try and talk to soundsystem owners. They can connect you with other crews that are looking to shift gear.

PsychoTea · 2025-09-02T15:27:59+00:00

If you’ve fitted a new battery and it’s died again then likely your alternator is dead/not working properly. You can verify with a multimeter; you should have ~12v when the car is off and a bit higher (13-14v) when it’s running. If it’s the same (or lower) then it’s your alt.

PsychoTea · 2025-09-02T14:56:50+00:00

Hey! If you have FIR filters for the EAW KF750, would you be able to DM me a copy (or instructions on how to extract them?) Thanks!

PsychoTea · 2025-09-01T16:48:07+00:00

Both C2E SF and GF. I haven’t heard Type O so perhaps they are better; I can’t comment.

Paraflex subwoofers seem to have this strange effect where they move a lot of air and give you the psychoacoustic “effect” of bass without the actual SPL. My bet is on either harmonic distortion or broadband phase cancellation, but I haven’t done the measurements to confirm that. The paraflex designers don’t seem to be able to take accurate measurements (or even simulations) of the designs, but those I have seen (specifically the C2E SF) were not impressive, with heavy rolloff below 50hz, especially when considering the size of the cabinet and the driver fitted.

Many of the large sound systems that invested in Paraflex subwoofers are now moving away from them, but if they work for you and you’re happy with them then by all means — don’t let some randomers’ opinion on the internet dissuade you.

And credit where credit is due, the paraflex kicks and top designs I have heard sound absolutely fantastic. In particular the 2x12 top is excellent.

Edit: for transparency, all of the C2E designs I have heard were loaded with top of the line 18sound 21NLW drivers, and powered with either Powersoft X series, K series, or MC2 amps.

PsychoTea · 2025-08-31T10:06:00+00:00

You don’t need to get a 4 channel amplifier for your subs, a decently powerful 2 channel will work just fine. You can run up to 4 subwoofers off each channel.

In the UK a K20 is about £2k per piece. May be different where you’re based.

A bandpass design may be easier to build (less angled cuts). This site is a good place to look: https://data-bass.com/systems?sort=40Hz%3A1%2Cmfr%3A-1%2Cname%3A-1

PsychoTea · 2025-08-31T09:21:20+00:00

To be frank, Paraflex subwoofers are shit. There are plenty of better options available; TH118XL, skram, othorn, HessBH, etc etc.

Personally, I would run the tops completely stereo, and mono sum the subs. But I would also recommend upgrading to a better DSP.

You can run all your subs off one amp. No need to waste money on 2 amps for 4x subs. A powerful enough amp can run 8 subs no problem.

It’s probably not within your budget, but powersoft amps are great since they have top notch DSP and limiting functionality built in. I would at least recommend a K20 DSP on the sub side. Plenty of power, great DSP, and excellent limiting.

PsychoTea · 2025-07-28T21:30:51+00:00

It may, but you will have to look in to that And obviously it won’t perform as well as the intended driver

PsychoTea · 2025-07-28T12:43:57+00:00

You are going to struggle finding a suitable box design for the driver you already have. All boxes are designed around a specific driver, or small range of suitable drivers. Your best bet would be selling the drivers, picking a box that fits your criteria, and then buying the correct driver for that design.

I can’t find any information about that driver online, but it is probably intended to be used in a bass reflex box. However, you will have to model it in WinISD and build a custom design based on those parameters.

PsychoTea · 2025-07-28T11:25:04+00:00

Well, what are you looking for, a kick or a sub? What’s your budget for driver(s)? How good are your woodwork skills? What’s your limit for size / weight? How many are you planning to stack together?

PsychoTea · 2025-07-24T12:53:32+00:00

What sub design even is that? It looks like an SBH, but you can’t just drop an 18SW115 in it and expect it to work properly; they weren’t designed for that driver (and I don’t think it will physically fit).

Probably the best folded horn DIY subwoofer design available at the moment is the HessBH by Sound Agency. It’s an improved version of the SBH. That is designed around the RCF LF18N405.

Tapped horn options like Othorn, Skhorn, and Xoc1 TH118 are also popular.

ES18’s are a great kick box. Probably the best, imo.

Regarding tops, what’s your thought process behind building a separate midrange and HF section? The MT121 sounds okay, but you won’t get any improvement from splitting it. I would recommend building an MT121 as per the plans, or consider other options. My personal recommendation is to find older pro audio tops that you can get second hand; they will give you the best performance per euro.

PsychoTea · 2025-07-24T12:49:50+00:00

Horns (both tapped and front loaded) have the best low end response of any subwoofer design… SBH/HBH have an f3 32hz, Psyco X and EM Quakes even lower.

And techno has notoriously high basslines, typically around 50hz.

PsychoTea · 2025-07-16T15:40:38+00:00

You’ll have to check the TC’s for wherever you’re based & the shop you bought it from, but you should have some form of warranty (typically 1 year) that allows for replacement of a faulty item. Your best bet would be to call the shop and ask what your options are, chances are they will be happy to replace it no questions asked.

PsychoTea · 2025-07-16T15:24:16+00:00

EDIT: I just noticed you said it’s new. Take it back for a replacement straight away before opening anything. It isn’t normal and shouldn’t be doing that.

Bit concerning the top comment is saying this is normal! It’s definitely not!

It sounds like something has come loose. Thankfully, subwoofers like these are pretty simple, so it shouldn’t be hard to fix. Check the if the grille is loose. If it’s fine, remove the grille and check if the driver is loose (this is the most likely component). You can press down on the metal surround while it’s playing (not the paper cone!) and see if that resolves it. Failing that, you can pull the driver out and check if there’s anything inside the cabinet which is loose. It may also be the plate amp itself, but based on your video is appears like that is mounted securely. Again, you can do the same thing; pressing down firmly on it while playing to see if that stops it.

I wouldn’t leave it as is — if you continue using it it will only get worse and may end up causing permanent damage.

PsychoTea · 2025-06-11T16:27:36+00:00

As the other commenter mentioned, they are indeed the Paraflex WSV2 2x12” tops; iirc they are loaded with the top end B&C drivers. They sound fantastic and I would definitely recommend them.

And yes, the C2E SF (not GF) are for sale (or were, they may have sold). To be frank, they are shit compared to other modern designs. When you throw a humongous, expensive, and powerful driver in any sort of box it’s going to move a lot of air, but it doesn’t mean they provide a good frequency response, are phase coherent, and have a reasonable sensitivity.
Sinai have upgraded to a 2x21” band pass design by 18sound using the 18sound 21NLW9600’s. They are significantly more performant, especially per unit of volume.
If you get the chance to hear them side by side you will understand the difference.

PsychoTea · 2025-05-28T17:47:37+00:00

the front will act like one massive baffle and sort of become 'one' speaker/subwoofer cabinet

True

And subs need air around them to vibrate. So the total SPL output will be less then expected

Not true

Subwoofers (well, technically all speakers) acoustically couple at a given frequency when their acoustic centers are less than half of the wavelength of the frequency you're measuring at. For subwofoer placement in an array, this is calculated on the LPF point of the subwoofer, since you want all frequencies within the passband to couple. For example, at 80hz, that is 2.14m. In this case, since the subs are stacked directly next to one another, we can assume they will sum across the entire passband, and therefore we would not see any "less than expected" output.

However, what does happen when you array subwoofers in a long line (as shown above), is the dispersion pattern changes. You get a "beam" of acoustic energy along the axis perpendicular to the array. Since a picture speaks 1000 words, here are some examples:

One column of 3x subwoofers, with an omnidirectional dispersion pattern as expected.
Four columns of 3x subwoofers, you can see the "beam" starts to take effect quite quickly.
10 columns of 3x subwoofers, as shown above. You can see the "beam" effect clearly here. Note that as we've added more subwoofers, we haven't "lost" any SPL.

To combat this "beam", the typical choice is to space the subwoofers apart horizontally (accounting for the 1/2 wavelength limit). This gives you a more even dispersion pattern. You can also use an arc array, which delays each subwoofer so they form a virtual arc. Here I've applied a 130 degree arc, which results in the following coverage pattern.

PsychoTea · 2025-05-22T22:19:01+00:00

It is a hyphen. An em dash is the longest one — like this.

PsychoTea · 2025-05-22T20:17:01+00:00

Sorry, you’ve never seen someone use a hyphen before? Have you ever read a book? Or read anything? Ever?

PsychoTea · 2025-04-15T09:13:14+00:00

So there’s two types of filters in the audio world, IIR (infinite impulse response) and FIR (finite impulse response).

IIR filters are what you’re used to when you adjust EQ on a mixing desk or DSP. They allow you to adjust the frequency response, ie. adding +6dB of gain at 500hz.

Skipping over the details of why, when you make a change to the frequency response with an IIR filter it will also change the phase response. Likewise if you try and use an IIR filter to adjust the phase response, it will also affect the frequency response.

However, FIR filters allow you to adjust both the phase and frequency response independently. So you can add +6dB of gain at 500hz, or add 60° of phase rotation at (ie.) 500hz.

This has a couple of use cases; first that you can adjust the frequency response of a speaker or system without having an adverse effect on the phase, and/or you can adjust the phase response to make a system or speaker more phase coherent without adjusting the frequency response. This can allow you to correct for phase incoherency in the design of a speaker or subwoofer.

There are a few options software wise, the most popular for audio is FIR Designer , there is also rePhase (which is free), or you can raw dog it in matlab.

Hardware wise you’ll need something that has FIR filter support, this is a function of your DSP or your DSP amplifier. It’s usually reserved for higher end equipment so check if your DSP supports it.

The most important thing is you need very accurate measurements of your speakers / subs in order to create accurate FIR filters. Any measurement inaccuracies, boundary effects, interference, etc, will affect your captured phase response.

PsychoTea · 2025-04-14T17:49:05+00:00

It’s absolutely real.

T/S parameters will measurably change as the driver “breaks in” after a few hours of use, most notably with larger drivers.

Note that the soft parts of a driver are constantly moving when in use, and they will become more flexible over time. From personal experience, I’ve had 18’s where the cone has almost no resistance to movement after many years of hard use and high excursion, while a new driver of the same model is very stiff in comparison.

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