Hello,
i never build a enclosure yet, but have been studying and simulating in winisd some possible projects with two types of speakers i have
i always design the box the way i could get the more bass possible, thinking that will be the best final response of the enclosure im my room
but i saw the Scott Lindgreen video in NWAS 2018 saying that he consider the room gain when designing a speaker letting the bass part of the spectrum a little shorter then desired because when in the room the bass will be reinforced and the box will deliver the desired full response
i find this video where he show how to estimate the room gain while desigining the speaker, so we can see if it will match our desired final response when playing in the real life of our rooms
my question is:
this method is ok to do?
because i am a fraid i will design a speaker with the most bass possibel in the winisd and when palying in my room it will sound boomy or not good because the room gain that i dont consider in the project
thank you
i never build a enclosure yet, but have been studying and simulating in winisd some possible projects with two types of speakers i have
i always design the box the way i could get the more bass possible, thinking that will be the best final response of the enclosure im my room
but i saw the Scott Lindgreen video in NWAS 2018 saying that he consider the room gain when designing a speaker letting the bass part of the spectrum a little shorter then desired because when in the room the bass will be reinforced and the box will deliver the desired full response
i find this video where he show how to estimate the room gain while desigining the speaker, so we can see if it will match our desired final response when playing in the real life of our rooms
my question is:
this method is ok to do?
because i am a fraid i will design a speaker with the most bass possibel in the winisd and when palying in my room it will sound boomy or not good because the room gain that i dont consider in the project
thank you
Hi,
As a side question to your goal, if you have too much free bass from the room itself, you can always EQ it down. I would not model with room gain. Always accept additional gain and simply EQ it down if you need to.
Very best,
As a side question to your goal, if you have too much free bass from the room itself, you can always EQ it down. I would not model with room gain. Always accept additional gain and simply EQ it down if you need to.
Very best,
Room gain does not tend to happen in real rooms, they are normally too lossy for that. There are various things that can happen at lower frequencies. You should aim to get balanced bass across your room and it's something to measure when you get to it.
Short answer is, for most houses, don't count on getting all of that because the room (wall construction) matters, but plan for a little.
Longer answer is that air-to-wall is an interface change and some energy is reflected, some absorbed, some transmitted and the only way to Know how your walls "work" is to measure. In general, "dense" materials are good reflectors, but also good transmitters at LF. Conversely, a lot of LF goes right through drywall, etc.
Material-specific curves and data may be found in construction materials datasheets. Data in that world is sort of the inverse--they refer to transmission-losses (note: "STC" is a single number and is about speech-frequencies much more than LF, BTW, and the properties are all freq-dependent Curves) and there's approximately no end to it for every conceivable application.
As a dirty first-approximation, maybe think of room gain itself rolling-off as freq drops instead of being flat (to apply transmission-loss "windage" to your design targets). You will get some over some bandwidth, but only your house knows and it likely wont be as much as that Linkwitz-in-ISD approach gives. Approximation is a good word, as Erin emphasized.
IMO, the size of your room has much more to do with how much extension you get than typical home wall construction room gain. You can play with the room sim tool in REW to get somewhat of a feel for that.
If you have a big room and you design flat to 30, you will likely have too much bass. Beyond that, we are all chefs with our own targets for rolloff locations and shapes. You will get a feel for your own rooms...and then have to move where that no longer works 🙂
Longer answer is that air-to-wall is an interface change and some energy is reflected, some absorbed, some transmitted and the only way to Know how your walls "work" is to measure. In general, "dense" materials are good reflectors, but also good transmitters at LF. Conversely, a lot of LF goes right through drywall, etc.
Material-specific curves and data may be found in construction materials datasheets. Data in that world is sort of the inverse--they refer to transmission-losses (note: "STC" is a single number and is about speech-frequencies much more than LF, BTW, and the properties are all freq-dependent Curves) and there's approximately no end to it for every conceivable application.
As a dirty first-approximation, maybe think of room gain itself rolling-off as freq drops instead of being flat (to apply transmission-loss "windage" to your design targets). You will get some over some bandwidth, but only your house knows and it likely wont be as much as that Linkwitz-in-ISD approach gives. Approximation is a good word, as Erin emphasized.
IMO, the size of your room has much more to do with how much extension you get than typical home wall construction room gain. You can play with the room sim tool in REW to get somewhat of a feel for that.
If you have a big room and you design flat to 30, you will likely have too much bass. Beyond that, we are all chefs with our own targets for rolloff locations and shapes. You will get a feel for your own rooms...and then have to move where that no longer works 🙂
A lot depends on what kind of room, the size and the way walls are build make a difference and it's a very complex thing to calculate so it's better not to take it in account when building speakers and use eq when needed.
Most american and a lot of modern european homes won't gave much room gain, as the rooms are to small and often made of wood frame with drywall and a lot of isolation. Those kind of walls don't stop the bass enough to load the room and give a lot of gain. And if they stop the bass the isolation in the wall act as a kind of basstrap.
It's mostly an issue in big rooms with hard stone or concrete walls without any isolation from the inside. But even the centuries old farmhouse i live in with very thick brickwalls, has a relative good acoustics because of the thick isolation put against it from the inside, covered with plaster. It's only some inside walls that are still exposed bricks, and they don't do much on their own. My biggest problem on acoustics is the hard stone floor, not the walls. And if it would stil be that your room is like that, then acoustic treatment will be needed anyway because to much bass will be the last of your issues...
Most american and a lot of modern european homes won't gave much room gain, as the rooms are to small and often made of wood frame with drywall and a lot of isolation. Those kind of walls don't stop the bass enough to load the room and give a lot of gain. And if they stop the bass the isolation in the wall act as a kind of basstrap.
It's mostly an issue in big rooms with hard stone or concrete walls without any isolation from the inside. But even the centuries old farmhouse i live in with very thick brickwalls, has a relative good acoustics because of the thick isolation put against it from the inside, covered with plaster. It's only some inside walls that are still exposed bricks, and they don't do much on their own. My biggest problem on acoustics is the hard stone floor, not the walls. And if it would stil be that your room is like that, then acoustic treatment will be needed anyway because to much bass will be the last of your issues...
I don't have time to watch online videos so can't comment on that I'm afraid. However, for a moderate alternative perspective on some of the posts above: from my POV designing to a maximally flat / similar type of alignment with no consideration for possible room effects is asking for trouble -especially if the design is not for you, but intended for relative flexibility in a reasonable range of situations, and you have little or no opportunity of providing individuals with guidance in optimising tuning to their particular requirements. With the best will in the world, neither I nor anybody else here can be in all places at all times.
It's also fair to say that my experience of room gain (termed in a deliberately lumped / generalised fashion for the sake of brevity) or a lack thereof differs from some of those expressed above. I don't disagree -many thin-wall / dry-wall rooms leach LF for example. But it's far from being universal. The overwhelming majority of UK homes & rooms I have been in for example very definitely result in a significant, measurable boost in part of the lower registers [which depending on detail, positioning &c.], and relatively few people have the luxury of possessing a dedicated space where they have the freedom to apply acoustic damping. In the same vein -not everybody has, or wishes to use, EQ. We live in a world of varying shades of grey rather than black & white, which gives plenty of room for all. I simply provide people with, or point them in the direction of, what I have found to be consistently 'practical' in a wide variety of situations, which as far as vented alignments go usually (though not invariably) means some form of modestly damped LF alignment. Others disagree -fair enough.
It's also fair to say that my experience of room gain (termed in a deliberately lumped / generalised fashion for the sake of brevity) or a lack thereof differs from some of those expressed above. I don't disagree -many thin-wall / dry-wall rooms leach LF for example. But it's far from being universal. The overwhelming majority of UK homes & rooms I have been in for example very definitely result in a significant, measurable boost in part of the lower registers [which depending on detail, positioning &c.], and relatively few people have the luxury of possessing a dedicated space where they have the freedom to apply acoustic damping. In the same vein -not everybody has, or wishes to use, EQ. We live in a world of varying shades of grey rather than black & white, which gives plenty of room for all. I simply provide people with, or point them in the direction of, what I have found to be consistently 'practical' in a wide variety of situations, which as far as vented alignments go usually (though not invariably) means some form of modestly damped LF alignment. Others disagree -fair enough.
Last edited:
Depends on the construction.
Here's the anechoic response of my current HiFi speakers:
Here's what I get at my listening position:
I end up using EQ to reduce the amount of bass, where the simulations (and close-mic'd measurements) suggest I'll need considerable amounts of boost.
Chris
Clearly there is a lot going on down there. Not so clear that there's not a Helmholz resonance working with the room losses, certainly some modes higher up.
https://www.diyaudio.com/community/threads/multiple-small-subs-geddes-approach.134568/post-1734701
https://www.diyaudio.com/community/threads/room-modal-response.248717/post-3795180
https://www.diyaudio.com/community/threads/multiple-small-subs-geddes-approach.134568/post-1734701
https://www.diyaudio.com/community/threads/room-modal-response.248717/post-3795180
I suspect we're at the risk here of getting into a state where there is 'assumption of ignorance, in response to prior application of brevity'.
As a broad observation: on many occasions, for the sake of simplicity, time constraints or other practical limitations at that moment in history, people will use 'room gain' as a brevity term to cover a variety of room-related LF considerations they are not in a position to break down into their component matters -just as 'bass reflex' has become a generic for 'vented box' (not strictly accurate), and 'TL' for all manner of quarter-wave designs (ditto). The general point remains independent of the specific mechanism of a given case.
As a broad observation: on many occasions, for the sake of simplicity, time constraints or other practical limitations at that moment in history, people will use 'room gain' as a brevity term to cover a variety of room-related LF considerations they are not in a position to break down into their component matters -just as 'bass reflex' has become a generic for 'vented box' (not strictly accurate), and 'TL' for all manner of quarter-wave designs (ditto). The general point remains independent of the specific mechanism of a given case.
To assume that one has the time/energy/money, wouldn't it be best to build upon a design that is corrected for the room it will be used in? This means build the prototype, measure, listen and then adjust the design of the cabinet, drivers to accommodate the results. I see this as being a possibility at least for the bass.
I made a set of speakers with the help of an engineer who led me in the right direction. Then I moved🤣
I made a set of speakers with the help of an engineer who led me in the right direction. Then I moved🤣
That's certainly one ideal, if you can't go down the Harman route. Of course, we're talking ideals, or at least very good solutions here, which not everybody is in a position to be able to implement (or wishes to for one reason or another). Which drops us back in those shades of grey again. 
Maybe closer than trying to model for every problem, the room/speaker combination would address such things as suck out in a room at 40hz filled by a bump at that frequency from the speaker. Not very close, I know, but beats the idea of a speaker and the listening room both having a suckout or bump at the same frequency. In other words, measuring the room with different speakers and finding one that works best with the room. I am speaking mostly of frequencies below 200hz of course. It just seems that a designer would have a leg up knowing both room and speaker responses.