Aperiodic: That which does not have periodic resonance, for which any return to it may occur at irregular times; not periodic. The term aperiodic literally means an absence of resonances at any specific frequency or multiple thereof. Aperiodic damping is defined as “damping of such a high degree that the damped system, after disturbances, comes to rest without oscillation or hunting” (Turner 1988).Hou la!Too much complicate for me.... -seems the drivers selection and filter correction with the passive way is for experienced guys-
A sealed system has one flaw, it allows for pressure buildup (visible at Fb), the pressure impedes the cone movement in both direction, meaning the air inside the box is very reactive close to and at Fb (Fb is the tuning frequency of the box).
So what is APL? What follows is a popular description: “An Aperiodic Speaker Enclosure is essentially a poorly sealed box (i.e. leaky). The aperiodic enclosure vents the inside of the box to the outside air through a damped ported (a port stuffed with damping material), which is sometimes referred to as an "acoustic resistor" or "resistive port/vent". The purpose of an aperiodic design is to allow a smaller enclosure size than would normally be possible in a sealed box. If a driver is placed into a sealed box that is too small, the result will be a high Q, which will cause a peak in the lower frequency response and a high impedance peak. By allow air to leak from the enclosure, both the frequency response and impedance peaks are tamed. This results in clearer, better defined bass, with more amplifier power and control into the lower frequencies.”
Source: Aperiodic Loudspeaker Enclosure Design
During my R&D of APL, I collected and constructed my own definition of what aperiodic load is.
· APL is a resistive hole in the enclosure as such that a certain amount of pressure inside the enclosure is needed in order to vent or leak air to the outside. As it does this, the pressure inside the cabinet drops. It is therefore said that APL enclosures has less resonance than other cabinets because the vent act as a pressure release valve.
· This causes less resistance on the driver which can be seen in the impedance graph.
· APL starts its life as a sealed cabinet and the vent will only impact the performance at tuning frequency, above the tuning frequency the vent becomes acoustically invisible and the enclosure is fully restored to its sealed property’s.
· The aperiodic vent serves two purposes: Release the pressure and act as acoustical cancelation.
· When designing the vent, one has to consider and take into account that we still need to deal with acoustic cancelation between the front- and back wave. Therefore, the quality of the vent will vary wildly.
Another effect of APL is that because it has less affect on the impedance at Fb, the amplifier can deliver more current or power if you like, this pushes the SPL up higher compared to a sealed enclosure.
And you now know much more about Aperiodic enclosures than the majority out there
my non-box bread container works very well for the MA Pluvia 7PHD. Closest thing would be APL but the rear foam is very thick so almost acting closed with just some venting. I detect no major dips or peaks, I am using it 300 Hz to 6 KHz. One day; I'll get the M-Audio and calibrated mic. going with REW, etc. Unfortunately, all of my projects are on hold as I had a very nasty fall a few weeks ago and really messed up my back and left hip...OUCH!!! No broken bones but very stiff and sore, can barely move so any physical activity is seriously limited...
I like the Aperiodic idea for mids and full range, one can adjust the density and thickness very easily to obtain optimum results and it is also very inexpensive compared to some other enclosure styles...
I like the Aperiodic idea for mids and full range, one can adjust the density and thickness very easily to obtain optimum results and it is also very inexpensive compared to some other enclosure styles...
Sorry to hear about your accident, hope you are doing better for each day that pass
Sealed cabinets tend to be detailed or accurate, have articulation, tightness and speed (good transients). Transient response: the response of a system to change from an equilibrium or steady state. Essentially, it’s the driver’s ability to stop and start the music transients (transition) and not having any overhang, ringing or sloppiness. A driver or loudspeaker which has relatively poor transients will blur or smear the musical transients and we start to lose details and accuracy.
The lower the transient response the more of a signature the loudspeaker will present, such as seen in the cumulative spectral-decay the Wharfedale Jade 7 and Bowers&Wilkins 802d2. Ported loudspeakers can present a greater output, but it does so with a huge penalty. Ports also contain or have attributes that is called scuffing, that is to say that the port breaths and you can hear air moving in and out of it. This is a negative acoustical attribute. One simple way to view the difference between sealed and ported is that the former lie less.
Lets not forget that the acoustic event from the port is 180 degree out of phase with the driver output.
Why is ported so popular you might ask and a possible answer might be; in part we are used or accustomed to them and we want high amount of bass output in a relatively small enclosure and we can do so by cheating. Producing ported enclosure is easier than sealed & aperiodic, because the ported enclosure will mask any defects or issues the woofers may contain. Therefore the demand on the engineer who designs sealed and aperiodic is larger.
The question is: what type of customer or listener are you? I think it’s fair to say that if you come from a well-designed and executed sealed or aperiodic enclosure, you might find it difficult to deal with a transition to ported enclosures. Coming from ported enclosure with the goal of increasing the musical quality and accuracy, you might have less difficulties than the former.
Let’s look at a technological comparison; Your standard car use a suspension type called MacPherson while your sport- or F1 car use something called Double wishbone suspension. (Look them up). The former has less demands on performance than the later, that is to say; they are not built equally and can never perform equally under high performance tests on a track. Anyone who claim they can is either lying or ignorant. You might have a decent or good MacPherson suspension but it can never claim to be a Double wishbone suspension no matter how much it tries.
One is more optimized for performance, safety and accuracy while the other is just okay.
A well-engineered ported enclosure will be, for many, a good compromise as a daily companion, it might never offend anyone in particular and maybe you can get away with it because no one ever asks the right question. But be aware of what you sacrifice in choosing such a loudspeaker. Our choices is a reflection of how we listen to music: casually or critically.
If there is one thing to take away from all of this, then that is: Price is not necessarily an indication of performance and few if no loudspeaker producer will show you the most important part of their loudspeaker, which is that which you cannot see.
Sealed cabinets tend to be detailed or accurate, have articulation, tightness and speed (good transients). Transient response: the response of a system to change from an equilibrium or steady state. Essentially, it’s the driver’s ability to stop and start the music transients (transition) and not having any overhang, ringing or sloppiness. A driver or loudspeaker which has relatively poor transients will blur or smear the musical transients and we start to lose details and accuracy.
The lower the transient response the more of a signature the loudspeaker will present, such as seen in the cumulative spectral-decay the Wharfedale Jade 7 and Bowers&Wilkins 802d2. Ported loudspeakers can present a greater output, but it does so with a huge penalty. Ports also contain or have attributes that is called scuffing, that is to say that the port breaths and you can hear air moving in and out of it. This is a negative acoustical attribute. One simple way to view the difference between sealed and ported is that the former lie less.
Lets not forget that the acoustic event from the port is 180 degree out of phase with the driver output.
Why is ported so popular you might ask and a possible answer might be; in part we are used or accustomed to them and we want high amount of bass output in a relatively small enclosure and we can do so by cheating. Producing ported enclosure is easier than sealed & aperiodic, because the ported enclosure will mask any defects or issues the woofers may contain. Therefore the demand on the engineer who designs sealed and aperiodic is larger.
The question is: what type of customer or listener are you? I think it’s fair to say that if you come from a well-designed and executed sealed or aperiodic enclosure, you might find it difficult to deal with a transition to ported enclosures. Coming from ported enclosure with the goal of increasing the musical quality and accuracy, you might have less difficulties than the former.
Let’s look at a technological comparison; Your standard car use a suspension type called MacPherson while your sport- or F1 car use something called Double wishbone suspension. (Look them up). The former has less demands on performance than the later, that is to say; they are not built equally and can never perform equally under high performance tests on a track. Anyone who claim they can is either lying or ignorant. You might have a decent or good MacPherson suspension but it can never claim to be a Double wishbone suspension no matter how much it tries.
One is more optimized for performance, safety and accuracy while the other is just okay.
A well-engineered ported enclosure will be, for many, a good compromise as a daily companion, it might never offend anyone in particular and maybe you can get away with it because no one ever asks the right question. But be aware of what you sacrifice in choosing such a loudspeaker. Our choices is a reflection of how we listen to music: casually or critically.
If there is one thing to take away from all of this, then that is: Price is not necessarily an indication of performance and few if no loudspeaker producer will show you the most important part of their loudspeaker, which is that which you cannot see.
yes, I consider transient response just as important as phase and frequency. I did some vented (bass reflex) that were very good with transients as well. I used to do vented mostly; these days I do closed box mostly, sometimes Aperiodic. Many have heard me say this; as a former musician I feel I have an advantage because I have a very keen sense of hearing very subtle differences; those without a "trained ear" may miss entirely. This is why I almost always do my final tweaks and tunings by ear with very familiar recordings.
I also compared transient response to an automobile suspension system...FWIW...
I also compared transient response to an automobile suspension system...FWIW...
Ofc in the end it all matter, drivers, filter, cabinet, material, geometric shape and so forth. I have spent 5 years trying to understand and learn, and if there is one thing that stand out then that is; There is no perfect loudspeaker - there is only the one you like.
There, simple as simple can be
There, simple as simple can be
http://sbacoustics.com/wp-content/uploads/2020/05/2.5in-SATORI-MD60N-6.pdf
yeah, THAT would be a really good addition for sure (in TexTreme).
What do people think so far from those of you that have heard the above MD60??? What X/O freq. and order did you end up with? What did you like about the "sound"? What did you NOT like about the "sound". What drivers did you mate with it?
yeah, THAT would be a really good addition for sure (in TexTreme).
What do people think so far from those of you that have heard the above MD60??? What X/O freq. and order did you end up with? What did you like about the "sound"? What did you NOT like about the "sound". What drivers did you mate with it?
Thanks Oneminde, yup, Aperiodic, I'm a great fan on the paper when I read it!
The too much complicate was for the Duelend filter type in the sentence
Hope you will make a build thread as OldSG
OldSG : yes, sorry to hear about the fall ! Not too much the moment to go to hospital those days...
The too much complicate was for the Duelend filter type in the sentence
Hope you will make a build thread as OldSG
OldSG : yes, sorry to hear about the fall ! Not too much the moment to go to hospital those days...
I don't know much about Duelunds filter yet, but supposedly it is "all drivers in phase all the time" kinda deal. We still need time alignment (which is called Allpass filter for some odd reason) and BSC.The too much complicate was for the Duelend filter type in the sentence
Hope you will make a build thread as OldSG
So besides the Duelund filter which I need to spend time with, what would my loudspeaker consist of?
1) Bliesma T25B-6 Beryllium tweeter.
2) Probably the 5" MR13TX midrange.
3) Both the TW and MR will get tapered tube absorbers ala Vivid audio.
4) The woofer section will consist of 2x 7.5” SATORI MW19TX-8, mounted in parallel.
5) The cabinet internally will use soft absorbers on the side, top front etc and the bracers will get a porous ceramic type of material which will act as diffusers.
6.1) The cabinet will be made from 24mm HDF (High Density Fiberboard) .. so, relying on mass & stiffness. Something which is not a problem when dual opposing woofers are used, then we can use composite material.
6.2) Cabinet will use constraint layer damping.
7) The APL port will be located underneath the cabinet like Wharfedale and Audio Physics does, and also be made from the porous ceramic material
8) Cabinet design will inspired by Vimberg (a Tidal company).
9). XO will be located at the rear of the cabinet in a separate chamber and use an aluminium backplate ala Bowers & Wilkins 800d3 series (see image)
10) Because it is not a commercial product, it will be an open source project here at diya. In the end, all the information will be available.
This is some time away since I need to build my amps, DAC, preamplifier etc first. And I need equipment to build all of this, so I am on one big adventure so to speak
Thanks
I have collected information and learned for about 5 years including listening to multiple brands and studied what they do and why. The why part is sometimes difficult to comprehend because multiple large companies use the motivation of sale as an argument to green light something, which we typically would not do. Or the "expensive because we can" part. So my goal is to pull in all that which I know and wrap it up in a package that can withstand a true objective review.
Other TX Loudspeakers will have popped up before mine are finalized, in part due to needing development and in part due to finances. And like I mentioned, I have other gear I need to build first
I love my MR and MW 16 Satoris both, very hard to beat and now the TexTremes will do even better. I have been playing around with speakers for over 50 years now. I have the MA Pluvia 7PHD in parallel with the Satori MR16P. Very hard to beat combination; the level of micro-detail is nothing short of amazing (to my "trained ears" anyway). This is why I am hoping the new TexTreme 13 would at least equal or exceed my mid-band solution. As I said; I'm hoping for something like a very wide band mid, similar to a true full range for use from about 300 Hz all the way to 6000 Hz. Like the very best of MA or Fostex but with the muscle and better motor of a Satori. My experience in mids and full range tells me I am happiest when the band from 300 to 6000 Hz is done with all 1 driver and with using only a very high quality 1st order X/O for both LP and HP. This eliminates the undesirable phase shifts, etc. in the critical mid-band and sounds the most accurate and natural to my personal listening habits and tastes...