Considering upgrading to the new Spendor A5r speakers. They have removed the rear port from the previous A5 model. What do people consider to be the main benefits of a sealed enclosure?
Best wishes
Paul
Best wishes
Paul
SteveR750 said:Natural roll off, lack of bass humps and less likelihood of an unwanted interaction with the room, and less sensitive to positioning.
lindsayt said:Think about it a bit more. If you've got a large bass cone in a small sealed cabinet, playing loud transients, what effect is the air inside the box going to have on the cone? It's going to act like a spring and compress the transient. Put the bass cone in a huge sealed box and you don't get that spring effect. But huge size increases cost and decreases domestic acceptability. Speaker design is a series of compromises.
lindsayt said:Think about it a bit more. If you've got a large bass cone in a small sealed cabinet, playing loud transients, what effect is the air inside the box going to have on the cone? It's going to act like a spring and compress the transient. Put the bass cone in a huge sealed box and you don't get that spring effect. But huge size increases cost and decreases domestic acceptability. Speaker design is a series of compromises.
paulsue38 said:This probably describes what I need. I currenly have the Spendor A3 with Arcam A38 and Marantz Pearl Lite CD player. The A 3 is an amazing compact floorstander for its size, with lovely tonal qualities. However, the port arrangement, does perhaps, cause problems in my small room; with two deep alcoves and a bay window. I have to pull them right out into the room. I have introduced bass panels which have helped to extent. There is enough bass, but its not as well pronoucd as I would like. Sounds like the A5 may be ideal.
Best wishes
Paul
For a given, relatively thin thickness of cabinet, yes that may well be the case.matt49 said:lindsayt said:Think about it a bit more. If you've got a large bass cone in a small sealed cabinet, playing loud transients, what effect is the air inside the box going to have on the cone? It's going to act like a spring and compress the transient. Put the bass cone in a huge sealed box and you don't get that spring effect. But huge size increases cost and decreases domestic acceptability. Speaker design is a series of compromises.
It also reduces the stiffness and rigidity of the box leading to greater distortion because of resonances.
True, though I doubt very much that many large cabinets actually do have a wall thickness that's scaled up proportionately.lindsayt said:For a given, relatively thin thickness of cabinet, yes that may well be the case.
But who says anyone has to make huge cabinets with the same materials and thicknesses as small cabinets?
Think about this one. Beef up the cabinets and you'll get better rigidity. You'll also have much greater mass in a huge, thick cabinet with large drivers than you will with a small, thinner walled cabinet with small drivers. That mass will couple the speaker to the floor more. You'll also have a larger footprint for a more stable connection with the floor.
peterpiper said:there will always be arguments for and against certain designs, its what woks best in your room,,, of the ported speakers i have owned, i always tried them with the bungs in, never liked it, yet i like the sound of the kefs, my conclusion is , you should use the speaker as it was intented in its design, if a speaker is ported it was designed to sound best like that, likewise the sealed kefs would probably sound bad with a hole drilled in the back*shok*
peterpiper said:there will always be arguments for and against certain designs, its what woks best in your room,,, of the ported speakers i have owned, i always tried them with the bungs in, never liked it, yet i like the sound of the kefs, my conclusion is , you should use the speaker as it was intented in its design, if a speaker is ported it was designed to sound best like that, likewise the sealed kefs would probably sound bad with a hole drilled in the back*shok*
paulsue38 said:What do people consider to be the main benefits of a sealed enclosure?
hg said:paulsue38 said:What do people consider to be the main benefits of a sealed enclosure?
Compared to the same driver in a ported cabinet (assuming the driver is suitable for both) the main benefit is a cabinet half the size and, depending on how the room behaves, there might be more bass well below the roll off frequency. The ported cabinet will be about twice the volume and extend the bass deeper by about an octave. The better transient response does not really apply in a comparison like this because although the resonances of the ported speaker degrades the transient response more than the resonance of the sealed speaker it kicks in at a significantly lower frequency. For the frequency range above the roll-off of the sealed speaker the ported speaker is likely to have the better not worse transient response. Below the roll-off of the sealed speaker the sealed speaker has insufficient output compared to the ported speaker but relatively a better transient response. Unfortunately it is the room resonances that tend to dominate what we hear at these low frequencies and so this advantage is likely to count for little.
lpv said:peterpiper said:there will always be arguments for and against certain designs, its what woks best in your room,,, of the ported speakers i have owned, i always tried them with the bungs in, never liked it, yet i like the sound of the kefs, my conclusion is , you should use the speaker as it was intented in its design, if a speaker is ported it was designed to sound best like that, likewise the sealed kefs would probably sound bad with a hole drilled in the back*shok*
which Kef's are sealed exactly?
SteveR750 said:Given an average room (whatever that is, but a speaker designer must make that approximation), do you think a steady roll of a sealed box should in theory be less problematic than the deliberately enhanced resonance of a ported design?
peterpiper said:not sure about all kefs , but the q500 are sealed, with a couple of auxillary radiators complimenting the two driven units in a quite a compact floorstander , some reviews state the bass is lightweight, i dont find this at all,
hg said:Compared to the same driver in a ported cabinet (assuming the driver is suitable for both)
the main benefit is a cabinet half the size
Why? See my comment above.and, depending on how the room behaves, there might be more bass well below the roll off frequency. The ported cabinet will be about twice the volume
and extend the bass deeper by about an octave.
The better transient response does not really apply in a comparison like this because although the resonances of the ported speaker degrades the transient response more than the resonance of the sealed speaker it kicks in at a significantly lower frequency.
For the frequency range above the roll-off of the sealed speaker the ported speaker is likely to have the better not worse transient response.
Again, that's only if we've got similar sized bass drivers in our ported and sealed examples. A competent designer of sealed box speakers prioritising sound quality over marketability would ensure sufficient bass cone size and cabinet size to provide enough bass extension and bass quality.Below the roll-off of the sealed speaker the sealed speaker has insufficient output compared to the ported speaker but relatively a better transient response.
That may be true in some rooms. The echoey cave / modernistic minimalist type rooms.Unfortunately it is the room resonances that tend to dominate what we hear at these low frequencies and so this advantage is likely to count for little.
lindsayt said:Very few bass drivers are ideally suited for both. Bass drivers tend to be suited for either sealed box or ported cabinets.
lindsayt said:Why half the size? Surely it's up to the designer / marketing department how big the cabinet in any speaker is and not down to whether it's ported or not?
lindsayt said:For the same bass driver, yes. But surely the drivers that are put into any speaker are decided by the designer / marketing dept and not by whether the speaker is ported or not?
lindsayt said:Stick a larger driver into a sealed box and you'll get the same bass extension as a smaller driver in ported speaker. Make the driver much larger and you'll get more bass extension than the ported speaker. All at the expense of cost and domestic acceptability.
This is not my experience where it is mainly the room that determines the quality of the bass given sufficient cone area to generate the SPLs. In an untreated room one can make a case for a sealed speaker but this is less the case in a treated room.lindsayt said:Oh yes it does apply in the real world. Listen to a few different sealed boxes vs a few different sealed boxes and you'll soon discover which sounds more realistic in the bass.
If you use the software I linked to earlier it will do this for you. If you put the same driver in an optimum sealed and ported enclosures and look at the group delay you will see the ported driver actually has a better, albeit by a tiny amount, transient response above the frequency the sealed cabinet starts to roll off. Below this the ported cabinet has a significantly worse transient response but maintains a flat frequency response unlike the sealed cabinet.lindsayt said:You could even do single cycle measurements at various frequencies which would illustrate the problems with transient handling in ported speakers.
Because the two resonances in a ported speaker are at lower frequencies than the single resonance in the sealed speaker. So for frequencies just above the sealed box resonance the sealed box is being influenced by its one resonance whereas the ported speaker is not yet being influenced by either of its two resonances.lindsayt said:For the frequency range above the roll-off of the sealed speaker the ported speaker is likely to have the better not worse transient response.
Why? Surely that would all depend on factors other than whether the speaker is sealed or ported? Such as driver quality, size of cabinet, etc etc.
lindsayt said:That may be true in some rooms. The echoey cave / modernistic minimalist type rooms.
What if someone has, for example, a very well furnished room with lots of open bookcases filled with vinyl or books? IE a room that acoustically has some similarities to an anechoic chamber? IE a room with clean bass?
Indeed but the devices that do it effectively are all large and often best put in false walls and ceilings which is not always an option.lindsayt said:It's up to each of us how we furnish our rooms. Room resonance is something that can be controlled, if anyone wants to.