CA1158176A - Arrangement for damping and absorption of sound in rooms - Google Patents
Arrangement for damping and absorption of sound in roomsInfo
- Publication number
- CA1158176A CA1158176A CA000375237A CA375237A CA1158176A CA 1158176 A CA1158176 A CA 1158176A CA 000375237 A CA000375237 A CA 000375237A CA 375237 A CA375237 A CA 375237A CA 1158176 A CA1158176 A CA 1158176A
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- CA
- Canada
- Prior art keywords
- absorbent
- sound
- absorption
- ceiling
- arrangement according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT OF THE DISCLOSURE
An arrangement for damping and absorption of sound in rooms, and in particular to provide a sound damping even at very low frequencies e.g., 50 Hz and simultaneously improve speech comprehension in the entire room by reduction of the resonance time as well as to be able to vary the acoustic absorption and in that way even vary the resonance time over the entire part of the frequency area. The sound absorbents in the form of plates mats or the like are arranged at an angle with at least one corner area formed by the walls and ceiling of the room. In the corner area behind the absorbent an air volume is trapped so that the absorbent due to the sound influence has a membrane effect. The in-clination and for position of each absorbent can be varied individually or in group.
An arrangement for damping and absorption of sound in rooms, and in particular to provide a sound damping even at very low frequencies e.g., 50 Hz and simultaneously improve speech comprehension in the entire room by reduction of the resonance time as well as to be able to vary the acoustic absorption and in that way even vary the resonance time over the entire part of the frequency area. The sound absorbents in the form of plates mats or the like are arranged at an angle with at least one corner area formed by the walls and ceiling of the room. In the corner area behind the absorbent an air volume is trapped so that the absorbent due to the sound influence has a membrane effect. The in-clination and for position of each absorbent can be varied individually or in group.
Description
The present invention relates to an arrangement for damping and abs~orption of sound in rooms even at very low fre-quencies (50Hz) as well as the improvement of speech comprehen-sion in the whole room by lowering the resonance time.
It is often desirable to lower the sound pressure level in rooms through absorption. In rooms where both speech and music occur, this absorption should preferably give the same resonance time over the entire range of frequencies area of in-terest and which can be from 50-5000Hz. This is normally provided by a combination of different materials with varying sound ab-sorption coefficients in varying frequency intervals. Generally two different types of sound absorbents are possible namely those that are of porous material which are effective from a few hundred Hz and upward, or so called hard absorbents which give high absorption at low frequencies, but are not effective at high frequencies. The absorption coefficient for an absorbent with low resonance frequency is normally not high which demands that large areas are covered with absorbents to lower the resonance time. To meet the demands on resonance time in rooms such as classrooms, and which may not exceed 0.6 seconds in valid frequency range, an additional absorption surface is need-ed, which generally covers the entire ceiling. This in its turn results in a very poor acoustic surrounding. Since it is the lowest frequency range that determines the size of the additional absorption surface area, it has been natural to try to increase actual absorption of the material in these frequency ranges.
It is known that porous absorbents of mineral wool or such type provide an improved low frequency absorption when mounted as an inner ceiling at a distance to the existing ceiling.
The distance decides to a large degree how far down in frequency that sound is effectively absorbed. With a distance of e.g.
- 1- ~, ..
. ~
7 ~
30cm a reasonably good absorption down to approximately 300Hz is achieved. There are however limits as to how low an inner ceiling can be mounted and for practical reasons lowering of absorption to below 250Hz has not been possible. An absorbing inner ceiling gives maximum absorption at that frequency which coincides with a quarter wavelength between the absorbent and the existing ceiling.
It is also well known that a long resonance time negatively affects speech comprehension in rooms of different kinds and to lower resonance time acoustic absorbers of dif-ferent kinds have been introduced. The so far most common method is still to cover all or part of a room's ceiling with absorbents. A complete inner ceiling however absorbs even the early reflections which are needed for speech comprehension in the rear of the room, whereas it is true that partially covering inner ceiling with reflecting surfaces in the centre, aids the early reflections to reach the rear of the room, but gives a poor absorption. Both these methods of arranging the sound absorbents have minimal absorption under 200Hz.
The present invention provides a good low frequency absorption at the same time as resonance time is kept short, in for example auditoriums. The present invention also makes it possible to vary the resonance time, which is advantageous in for example, concert halls, theaters, churches and similar, where music, song and speech occur. In for example churches it is preferable with a straight resonance time curve during the sermon to increase speech comprehension, i.e. relatively short resonance time even in the lower frequency range, whereas during organ music a long resonance time is sought after in the lower frequency range.
According to the present invention there is provided an arrangement for damping and absorption of sound in rooms even at very low frequencies as well as for providing an im-provement of speech comprehension in the entire room by lower-ing of the resonance time, comprisins a sound absorbent in the form of a plate, mat or the like arranged at an angle with at least one corner area formed by the walls and ceiling of the room, onabsorption surface of the sound absorbent facing the interior of the room and an air space being present in the corner area behind the absorbent whereby under the influence of the sound the absorbent has a membrane effect.
The advantages of mounting accoustic absorbents dia-gonally between wall and ceiling in a room are many. Firstly a good absorption in the frequency ranged under 300 Hz and down even below 50 Hz is achieved. By choosing surface weight flow resistance and diagonal volume, maximum absorption can be adjusted to the frequency range required in a specific room Usage of the room's corners between wall and ceiling is es-pecially important since sound pressure in the room is great-est within this area. By placing diagonal absorbents in these areas the sound pressures behind the absorbents are damped, which gives a high pressure difference over the absorbent.
This difference results in high particle velocity in the air in the absorbent, which in turn results in great losses, i.e., high absorption. The pressure difference also accelerates the absorption plate itself. The plate and the air volume trapped behind form a resonance system with one or more resonance fre-quencies.
The present invention will be further illustrated by way of the accompanying drawings in which:-Fig. 1 is a section through a corner area of a room with a fitted sound absorbent according to one embodiment of the invention;
: , .
Figs. 2 to 8 show analogous sections through regard-ing their position and/or inclination adjustable sound absor-bents according to the invention;
Fig. 9 is a graph of sound absorption measurements;
and Fig. 10 is a graph of resonance time.
Referring to the drawings, a corner section 11 is formed between a wall 12 and a ceiling 13 of a room. A sound absorbent 14 in the form of an accoustic absorbing plate, of for example mineral wool, is placed diagonally - 3a -,-; .~, ,' ~ ' ' " ~ .
between said wall 12 and ceiling 13, so that a volume of air is trapped behind the absorbent 14. The mineral wool plate is suitably along the outer edges surrounded by a frame 16 having a U-shaped cross-section and which that stiffens the plate. A
number of absorbents 14, corresponding to the entire length of the room are supported by profiled metal holders 15, which are fastened to the wall 12 and the ceiling 13 and formed so that the absorbents can easily be put up or taken down. Suitably, such diagonal sound absorbents are arranged in the same room along two opposing corner areas. It can in certain cases be suitable to arrange an absorption plate 17 even inside the dia-gonal absorbent 14 as is shown in Fig. 1 with dash-dotted lines.
The span of the sound absorbents are adapted to the size of the room and the field of application and for an ordinary class-room for about thirty pupils a span of 0.5 m has proved to beappropriate. To be able to vary the acoustic absorption and resonance time over a large frequency area or only a part thereof it is possible to change the angle of inclination of the absor-bent 14 and/or its position, whereby the absorption peak can easily be moved on the frequency range. The different pos-sibilities to vary the absorbent'sposition or angle is shown in Fig. 2-8.
Fig. 2 shows an absorbent 14, which with its ends facing the wall 12 and the ceiling 13 are constructed with guiding means 18, which cooperate with guides 19 arranged along the wall and ceiling. The guides have such a length, that the afisorbent 14 can take every possible position from a position parallel to the wall to a position parallel to the ceiling.
Fig. 3 shows an embodiment where the absorbent 14 along its one edge is movably suspended in bearing means 20 in the ceiling 13 or possibly at the wall 12. When placed against the ceiling the absorbent can either be used as a dia-gonal absorfient according to the invention, as a baffle in a vertieal hanging position or as a standard sound absorption ' unit in a position parallel to the ceiling. Even the bearing means 20 can possibly be adjustable in the guide 19, so that the angle between the absorbent 14 and the wall 12 can vary.
With the embodiment as in Fig. 4 the absorbent 14 is divided in two and on the side facing the room a hinge 21 is attached in the joint. Both end edges of the absorbent are guided in guides 19, so that the divided absorbent can be folded until in contact with the wall 12 and the ceiling 13, as shown by dash-dotted lines.
In the embodiment according to Fig. 5 the angle that the absorbent 14 makes with the wall 12 cannot be changed, but the absorbent is adjustable in height along a guide 19.
In these cases where a quick change of the character-istics of the absorbent is desired any of the arrangements shown in Figs. 6 or 7 can come to use.
In Fig. 6 is shown a fixed arranged absorbent 14 between wall 12 and ceiling 13, on one surface of which, pre-ferably the one facing the room, a reflector 22 can be attached, which in this em~odiment consists of a roll shutter 23 of an acoustic hard material. The covering at the roll shutter over the absorbent can easily be adjusted according to circumstances or needs and is manouvered either manually or with the assist-ance o~ small electric motors.
The same effect as with the embodiment according to Fig. 6 is achieved with the embodiments according to Figure 7 where in front of the abosrbent 14 a blind, a venetian blind 24 or the like is placed. With both of these in the Figs. 6 and7 ~ structions it is possible with the reflector in an active position to lower the high frequency absorption so that a long resonance time is obtained, whic~ may be desirable during e.g.
a serv~ce ~n a church, where during the sermon the absorkents are A, - :
:
exposed while during organ music the reflectors are placed in an active position.
The embodiment according to Figure 8 differs from the previous ones in that the absorbent 14 is a soft mat which is fixedly supported in a fastening at the ceiling 13 or walls 12 and at the other end is rollable about a rolling apparatus 25 that is guided in a guide 18. sy rolling up all of or part of the absorbent 14 the low frequency absorption is removed.
~ n the graph in Fig. 9 a measurement curve on a dia-gonal absorbent according to the invention is shown with con-tinuous lines and corresponding measurement curve performed in the same room, but fitted with an inner ceiling covered with the same absorption material as the absorbent according to the invention. In the graph the ordinate axis denotes the absorption coefficient and the a~s~issathe frequency in Hz. With a diagonal absorber according to the invention with a span of 0.6 m an absorption peak i.e. absorption coefficent of 1.4 at 160 Hz was achieved, while the same room with a conventionally formed ceiling with sound absorbents covering the ceiling completely achieved an absorption peak of 1.1 at 2500 Hz, (see dashed curve). At 160 Hz an absorption co-efficient of 0.3 Hz was achieved.
That suchhigh absorption coefficients were achieved with the use of diagonal absorbents according to invention can be explained in that the absorbents 14 throu~h their special fitting work as m~mhranous absorbents.
~nd the mineral wool plate 14 the sound pressure is very low, whereas it is high in front of the absorbent. A relatively large acceler-ation pressure affects the plate, which results in a high pres-sure difference through the absorbent and large particle move-ments and thereby friction losses i.e. high absorption. By the membrane movements these losses are increased and usually h.gh absorption coefficents are reached. The absorption peak through membrane action is dependent upon the materials flow .:
S
resistance, its surface mass (kg/m2) and rigidity. In one and the same material the rigidity varies with its length i.e.
span, the rigidity of the trapped air volume, which can be changed by varying the inclination of the absorbent. To form an even resonance time as a function of the frequency of a room, span and inclination are therefore changed. In the graph according to Fig. 10 measurements of resonance time (Ts) for three different cases in one and the same room are shown. On the ordinate axis of the graph the resonance time is given, and on its abscissa the frequency in HZ. With a continuous line is shown a classroom in which no sound damping actions have been done. The dashed line curve shoWs the same class- -room, but with an inner ceiling completely covered with sound absorbents. When the same classroom was then equipped with lS only diagonal absorbents according to the invention the dash dotted line-curve was achieved. From the graph it is shown that the resonance time, especially at low frequencies can be reduced by more than half.
It is often desirable to lower the sound pressure level in rooms through absorption. In rooms where both speech and music occur, this absorption should preferably give the same resonance time over the entire range of frequencies area of in-terest and which can be from 50-5000Hz. This is normally provided by a combination of different materials with varying sound ab-sorption coefficients in varying frequency intervals. Generally two different types of sound absorbents are possible namely those that are of porous material which are effective from a few hundred Hz and upward, or so called hard absorbents which give high absorption at low frequencies, but are not effective at high frequencies. The absorption coefficient for an absorbent with low resonance frequency is normally not high which demands that large areas are covered with absorbents to lower the resonance time. To meet the demands on resonance time in rooms such as classrooms, and which may not exceed 0.6 seconds in valid frequency range, an additional absorption surface is need-ed, which generally covers the entire ceiling. This in its turn results in a very poor acoustic surrounding. Since it is the lowest frequency range that determines the size of the additional absorption surface area, it has been natural to try to increase actual absorption of the material in these frequency ranges.
It is known that porous absorbents of mineral wool or such type provide an improved low frequency absorption when mounted as an inner ceiling at a distance to the existing ceiling.
The distance decides to a large degree how far down in frequency that sound is effectively absorbed. With a distance of e.g.
- 1- ~, ..
. ~
7 ~
30cm a reasonably good absorption down to approximately 300Hz is achieved. There are however limits as to how low an inner ceiling can be mounted and for practical reasons lowering of absorption to below 250Hz has not been possible. An absorbing inner ceiling gives maximum absorption at that frequency which coincides with a quarter wavelength between the absorbent and the existing ceiling.
It is also well known that a long resonance time negatively affects speech comprehension in rooms of different kinds and to lower resonance time acoustic absorbers of dif-ferent kinds have been introduced. The so far most common method is still to cover all or part of a room's ceiling with absorbents. A complete inner ceiling however absorbs even the early reflections which are needed for speech comprehension in the rear of the room, whereas it is true that partially covering inner ceiling with reflecting surfaces in the centre, aids the early reflections to reach the rear of the room, but gives a poor absorption. Both these methods of arranging the sound absorbents have minimal absorption under 200Hz.
The present invention provides a good low frequency absorption at the same time as resonance time is kept short, in for example auditoriums. The present invention also makes it possible to vary the resonance time, which is advantageous in for example, concert halls, theaters, churches and similar, where music, song and speech occur. In for example churches it is preferable with a straight resonance time curve during the sermon to increase speech comprehension, i.e. relatively short resonance time even in the lower frequency range, whereas during organ music a long resonance time is sought after in the lower frequency range.
According to the present invention there is provided an arrangement for damping and absorption of sound in rooms even at very low frequencies as well as for providing an im-provement of speech comprehension in the entire room by lower-ing of the resonance time, comprisins a sound absorbent in the form of a plate, mat or the like arranged at an angle with at least one corner area formed by the walls and ceiling of the room, onabsorption surface of the sound absorbent facing the interior of the room and an air space being present in the corner area behind the absorbent whereby under the influence of the sound the absorbent has a membrane effect.
The advantages of mounting accoustic absorbents dia-gonally between wall and ceiling in a room are many. Firstly a good absorption in the frequency ranged under 300 Hz and down even below 50 Hz is achieved. By choosing surface weight flow resistance and diagonal volume, maximum absorption can be adjusted to the frequency range required in a specific room Usage of the room's corners between wall and ceiling is es-pecially important since sound pressure in the room is great-est within this area. By placing diagonal absorbents in these areas the sound pressures behind the absorbents are damped, which gives a high pressure difference over the absorbent.
This difference results in high particle velocity in the air in the absorbent, which in turn results in great losses, i.e., high absorption. The pressure difference also accelerates the absorption plate itself. The plate and the air volume trapped behind form a resonance system with one or more resonance fre-quencies.
The present invention will be further illustrated by way of the accompanying drawings in which:-Fig. 1 is a section through a corner area of a room with a fitted sound absorbent according to one embodiment of the invention;
: , .
Figs. 2 to 8 show analogous sections through regard-ing their position and/or inclination adjustable sound absor-bents according to the invention;
Fig. 9 is a graph of sound absorption measurements;
and Fig. 10 is a graph of resonance time.
Referring to the drawings, a corner section 11 is formed between a wall 12 and a ceiling 13 of a room. A sound absorbent 14 in the form of an accoustic absorbing plate, of for example mineral wool, is placed diagonally - 3a -,-; .~, ,' ~ ' ' " ~ .
between said wall 12 and ceiling 13, so that a volume of air is trapped behind the absorbent 14. The mineral wool plate is suitably along the outer edges surrounded by a frame 16 having a U-shaped cross-section and which that stiffens the plate. A
number of absorbents 14, corresponding to the entire length of the room are supported by profiled metal holders 15, which are fastened to the wall 12 and the ceiling 13 and formed so that the absorbents can easily be put up or taken down. Suitably, such diagonal sound absorbents are arranged in the same room along two opposing corner areas. It can in certain cases be suitable to arrange an absorption plate 17 even inside the dia-gonal absorbent 14 as is shown in Fig. 1 with dash-dotted lines.
The span of the sound absorbents are adapted to the size of the room and the field of application and for an ordinary class-room for about thirty pupils a span of 0.5 m has proved to beappropriate. To be able to vary the acoustic absorption and resonance time over a large frequency area or only a part thereof it is possible to change the angle of inclination of the absor-bent 14 and/or its position, whereby the absorption peak can easily be moved on the frequency range. The different pos-sibilities to vary the absorbent'sposition or angle is shown in Fig. 2-8.
Fig. 2 shows an absorbent 14, which with its ends facing the wall 12 and the ceiling 13 are constructed with guiding means 18, which cooperate with guides 19 arranged along the wall and ceiling. The guides have such a length, that the afisorbent 14 can take every possible position from a position parallel to the wall to a position parallel to the ceiling.
Fig. 3 shows an embodiment where the absorbent 14 along its one edge is movably suspended in bearing means 20 in the ceiling 13 or possibly at the wall 12. When placed against the ceiling the absorbent can either be used as a dia-gonal absorfient according to the invention, as a baffle in a vertieal hanging position or as a standard sound absorption ' unit in a position parallel to the ceiling. Even the bearing means 20 can possibly be adjustable in the guide 19, so that the angle between the absorbent 14 and the wall 12 can vary.
With the embodiment as in Fig. 4 the absorbent 14 is divided in two and on the side facing the room a hinge 21 is attached in the joint. Both end edges of the absorbent are guided in guides 19, so that the divided absorbent can be folded until in contact with the wall 12 and the ceiling 13, as shown by dash-dotted lines.
In the embodiment according to Fig. 5 the angle that the absorbent 14 makes with the wall 12 cannot be changed, but the absorbent is adjustable in height along a guide 19.
In these cases where a quick change of the character-istics of the absorbent is desired any of the arrangements shown in Figs. 6 or 7 can come to use.
In Fig. 6 is shown a fixed arranged absorbent 14 between wall 12 and ceiling 13, on one surface of which, pre-ferably the one facing the room, a reflector 22 can be attached, which in this em~odiment consists of a roll shutter 23 of an acoustic hard material. The covering at the roll shutter over the absorbent can easily be adjusted according to circumstances or needs and is manouvered either manually or with the assist-ance o~ small electric motors.
The same effect as with the embodiment according to Fig. 6 is achieved with the embodiments according to Figure 7 where in front of the abosrbent 14 a blind, a venetian blind 24 or the like is placed. With both of these in the Figs. 6 and7 ~ structions it is possible with the reflector in an active position to lower the high frequency absorption so that a long resonance time is obtained, whic~ may be desirable during e.g.
a serv~ce ~n a church, where during the sermon the absorkents are A, - :
:
exposed while during organ music the reflectors are placed in an active position.
The embodiment according to Figure 8 differs from the previous ones in that the absorbent 14 is a soft mat which is fixedly supported in a fastening at the ceiling 13 or walls 12 and at the other end is rollable about a rolling apparatus 25 that is guided in a guide 18. sy rolling up all of or part of the absorbent 14 the low frequency absorption is removed.
~ n the graph in Fig. 9 a measurement curve on a dia-gonal absorbent according to the invention is shown with con-tinuous lines and corresponding measurement curve performed in the same room, but fitted with an inner ceiling covered with the same absorption material as the absorbent according to the invention. In the graph the ordinate axis denotes the absorption coefficient and the a~s~issathe frequency in Hz. With a diagonal absorber according to the invention with a span of 0.6 m an absorption peak i.e. absorption coefficent of 1.4 at 160 Hz was achieved, while the same room with a conventionally formed ceiling with sound absorbents covering the ceiling completely achieved an absorption peak of 1.1 at 2500 Hz, (see dashed curve). At 160 Hz an absorption co-efficient of 0.3 Hz was achieved.
That suchhigh absorption coefficients were achieved with the use of diagonal absorbents according to invention can be explained in that the absorbents 14 throu~h their special fitting work as m~mhranous absorbents.
~nd the mineral wool plate 14 the sound pressure is very low, whereas it is high in front of the absorbent. A relatively large acceler-ation pressure affects the plate, which results in a high pres-sure difference through the absorbent and large particle move-ments and thereby friction losses i.e. high absorption. By the membrane movements these losses are increased and usually h.gh absorption coefficents are reached. The absorption peak through membrane action is dependent upon the materials flow .:
S
resistance, its surface mass (kg/m2) and rigidity. In one and the same material the rigidity varies with its length i.e.
span, the rigidity of the trapped air volume, which can be changed by varying the inclination of the absorbent. To form an even resonance time as a function of the frequency of a room, span and inclination are therefore changed. In the graph according to Fig. 10 measurements of resonance time (Ts) for three different cases in one and the same room are shown. On the ordinate axis of the graph the resonance time is given, and on its abscissa the frequency in HZ. With a continuous line is shown a classroom in which no sound damping actions have been done. The dashed line curve shoWs the same class- -room, but with an inner ceiling completely covered with sound absorbents. When the same classroom was then equipped with lS only diagonal absorbents according to the invention the dash dotted line-curve was achieved. From the graph it is shown that the resonance time, especially at low frequencies can be reduced by more than half.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An arrangement for damping and absorption of sound in rooms even at very low frequencies as well as for providing an improvement of speech comprehension in the entire room by lowering of the resonance time, comprising a sound absorbent in the form of a plate, mat or the like arranged at an angle with at least one corner area formed by the walls and ceiling of the room, on absorption surface of the sound absorbent fac-ing the interior of the room and an air space being present ing the corner area behind the absorbent whereby under influence of the sound the absorbent has a membrane effect.
2. An arrangement according to claim 1, in which the inclination of each absorbent is adjustable individually or in a group.
3. An arrangement according to claim 2, in which at least one of the end edges of the absorbent located against the ceiling or the wall is guided by guides arranged in the ceiling or wall and the inclination of the absorbent is adjust-able in various positions between the horizontal and vertical positions.
4. An arrangement according to claim 2, in which the absorbent is pivotably hinged at one of its end edges facing the ceiling or the wall and is locatable in different angular positions.
5. An arrangement according to claim 2, in which the absorbent has two opposed end edges guided in guides, and the absorbent along a central joint is foldable around a hinge.
6. An arrangement according to claim 2, in which the absorbent is attached to a holder which is moveable in guides.
7. An arrangement according to claim 1, 2 or 3, in which a reflector is fitted over a section of the surface of the absorbent.
8. An arrangement according to claim 2, in which the absorbent is a mat arranged to be wound up along guide rails.
9. An arrangement according to claim 1, 2 or 3, in which the sound absorbent has a central sound-absorbing portion surrounded by frame of U-shaped cross-section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000375237A CA1158176A (en) | 1981-04-10 | 1981-04-10 | Arrangement for damping and absorption of sound in rooms |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000375237A CA1158176A (en) | 1981-04-10 | 1981-04-10 | Arrangement for damping and absorption of sound in rooms |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1158176A true CA1158176A (en) | 1983-12-06 |
Family
ID=4119710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000375237A Expired CA1158176A (en) | 1981-04-10 | 1981-04-10 | Arrangement for damping and absorption of sound in rooms |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1158176A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160092795A1 (en) * | 2014-03-07 | 2016-03-31 | Eventforte, Inc. | Methods and systems for configuring reservation space of venues |
-
1981
- 1981-04-10 CA CA000375237A patent/CA1158176A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160092795A1 (en) * | 2014-03-07 | 2016-03-31 | Eventforte, Inc. | Methods and systems for configuring reservation space of venues |
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