If anyone wanted proof that acoustic wavefront's can't be folded without consequences I don't think there is a more exquisite demonstration than EV's MTLs and the MTL4 in particular.
Of course Art is correct that all systems drop at 6dB per doubling of distance in the far field, which really isn't that 'far' from the cabinet. Air molecules vibrating in space don't really care much for what started them off.
Of course Art is correct that all systems drop at 6dB per doubling of distance in the far field, which really isn't that 'far' from the cabinet. Air molecules vibrating in space don't really care much for what started them off.
In a room the apparent bass at any point is dominated by the listener's position relative to nodes and antinodes for a given frequency; the speaker being the origin and an antinode, and the 'effective' boundaries being nodes. Even if two boxes are placed at the same location, the acoustic centre of the box will not necessarily be at the same point in space and therefore the system will not necessarily exhibit the same standing wave pattern.
W-bins, J-scoops and MTLs all have a very peaky power response and that will be reflected in the standing wave pattern in the room, i.e. some frequencies will really punch, others might almost disappear. When I was still wet behind the ears in pro audio I used to like JBL scoops for clean tight punchy bass; that was until I measured them in a ~150,000 cubic meter chamber in the free field and saw deep frequency notches. Someone who's paid $$$ for a ticket to a concert or to go to a club is entitled to hear all of the left hand notes of a piano, not just some IMHO.
W-bins, J-scoops and MTLs all have a very peaky power response and that will be reflected in the standing wave pattern in the room, i.e. some frequencies will really punch, others might almost disappear. When I was still wet behind the ears in pro audio I used to like JBL scoops for clean tight punchy bass; that was until I measured them in a ~150,000 cubic meter chamber in the free field and saw deep frequency notches. Someone who's paid $$$ for a ticket to a concert or to go to a club is entitled to hear all of the left hand notes of a piano, not just some IMHO.
My experience with the MTL4s was back in the '80s where on several occasions I hired a rig of 4 x MTL4 plus 4 x MTH4 per side for a 2000 seat auditorium. At the time it was the only large system available to hire within 700km. Because the event ran for a couple of weeks I allowed plenty of time for setup and tuning, and even had spare drivers supplied by the importer on backup. For the local hire company this gig became their system's free annual checkup (although I deducted parts from their invoice).
The MTL4s have a distinct grab-bag of resonant modes that colour the sound plus their own unique set of suck-outs. Of all of the scores of direct radiating reflex bass boxes that went through that venue over the years (Clair Bros, Meyer, Apogee, JBL, Turbosound, ARX, Jands, Krix, and even other EV bass boxes, the anti-direct radiating MTL4s would be my last choice for sound quality, surpassed only by bandpass systems (which I call two coke bottle sound).
The MTL4s have a distinct grab-bag of resonant modes that colour the sound plus their own unique set of suck-outs. Of all of the scores of direct radiating reflex bass boxes that went through that venue over the years (Clair Bros, Meyer, Apogee, JBL, Turbosound, ARX, Jands, Krix, and even other EV bass boxes, the anti-direct radiating MTL4s would be my last choice for sound quality, surpassed only by bandpass systems (which I call two coke bottle sound).
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If You would read the paper from Keele about the 18-W You would see it is designed for 8 units on each side of the stage. This will fill in the missing deep bass and deliver POUNDING BASS. This design is not for Home Stereo or Car Radio. I used these all the time in the 80s/90s doing sound for Bands. Room shaking Bass. Awesome outside. VECTORSONICS
Thank you sir! My experiences with the MTL rigs were the likes of KISS and AC/DC and they sure did the job for them but I admit there's not much fidelity there. Have any experience with tapped horns?
Curious how those Sentry bins will sound in my man cave nestled in the corners. Not expecting them to be a sub just curious how low. Got them mainly for mid bass 100-500hz.
Curious how those Sentry bins will sound in my man cave nestled in the corners. Not expecting them to be a sub just curious how low. Got them mainly for mid bass 100-500hz.
Was doing some reading and wanted to get the diamensions of the Jensen Imperial and came across this. I need to study and learn more.
These horns launch a very large wave front below 600 Hz. That makes bass response difficult to handle when compared to a smaller speaker. A smaller speaker having a tiny wave front creates dozens of nodes or pockets in your listening space where cancellation has created quiet or soft spots in the low frequency response. This is common with all speakers used in smaller residential listening rooms. It also makes it possible to arrange your speakers and listening chair so that you are not sitting in one of these nodes, the result being a frequency balance that has solid bass response. If you were to increase the wave front launching from the speaker to say 30 times it's original size, it would fill the room with greatly simplified cancellation, ie. less nodes. That might sound good, but it is actually bad because rather than resulting in dozens of complex standing waves that create the pockets where you will hear some bass, a large simple standing wave will have near perfect cancellation. The result is less pockets, and each pocket becoming very large. That makes it difficult to hear any low bass response when you are in the center area of the room. In fact you will probably have to sit against the back wall to hear any bass. In a perfectly square room it is possible to create an almost perfect standing wave. To listen to one is a puzzlement, because it is no different than having a 24dB active crossover set at 80 Hz. If you go outside your house or to the other end of your house it becomes quiet a different story. There you will hear the bass.
These horns launch a very large wave front below 600 Hz. That makes bass response difficult to handle when compared to a smaller speaker. A smaller speaker having a tiny wave front creates dozens of nodes or pockets in your listening space where cancellation has created quiet or soft spots in the low frequency response. This is common with all speakers used in smaller residential listening rooms. It also makes it possible to arrange your speakers and listening chair so that you are not sitting in one of these nodes, the result being a frequency balance that has solid bass response. If you were to increase the wave front launching from the speaker to say 30 times it's original size, it would fill the room with greatly simplified cancellation, ie. less nodes. That might sound good, but it is actually bad because rather than resulting in dozens of complex standing waves that create the pockets where you will hear some bass, a large simple standing wave will have near perfect cancellation. The result is less pockets, and each pocket becoming very large. That makes it difficult to hear any low bass response when you are in the center area of the room. In fact you will probably have to sit against the back wall to hear any bass. In a perfectly square room it is possible to create an almost perfect standing wave. To listen to one is a puzzlement, because it is no different than having a 24dB active crossover set at 80 Hz. If you go outside your house or to the other end of your house it becomes quiet a different story. There you will hear the bass.
I have minimal experience with tapped horns.
Your mention of KISS reminds me I was invited by JBL Professional to audition their Line Array system on its first outing in Australia at an 12,000 seat indoor arena, accompanying a KISS tour. I was also invited to stay for the performance in JBL's corporate box. The instant Kiss started playing the whole system went into severe clipping - the concert was merely syncopated noise. I lasted just one song.
I have fond memories of the Electro Voice Sentry IVs, though not because they were particularly good; they were however very cheap and a manageable size and used mainly for side-fill cabinets for ballet and dance productions at our venues. In the mid '80s I had to set up a 1200 seat opera theatre for an international film festival on a shoe-string budget. The front end was the poor man's Dolby Stereo decoder, the Ultra Stereo processor, feeding Inkel amplifiers and a left/centre/right array of three Sentry IVs behind a perforated projection screen, four EV 18" 'step-down' bass reflex cabinets for sub-bass, and a dozen or so Bose 101s for the surround array. I had collaborated with Krix, a local loudspeaker manufacturer, to upgrade the Sentry IVs with bracing and redesigned crossover with altered mid/bass transition frequency and additional horn equalisation on the mid. If I recall correctly the Ultra Stereo rack had five parametric equalisers per channel with ±6dB(!) boost/cut to compensate for screen-loss and room acoustics.
The opening film was Delicatessen, a French dystopian movie with a great soundtrack. In a full page newspaper review of the festival a lot of column inches were given to praising the quality of in-cinema sound reproduction and suggesting everyone should come and see Delicatessen, if only to hear just how good a cinema can sound!
We used to have a pair of W bins on a disco I worked for in the 1970's.
I think they were made by "Orange"
They had a pair of tweeters on each box to boost top end.
They actually sounded ok and very loud but maybe a little wooden sounding.
I have a built a couple myself and the box needs to be big to get both enough speaker volume and the vents in.
I think they were made by "Orange"
They had a pair of tweeters on each box to boost top end.
They actually sounded ok and very loud but maybe a little wooden sounding.
I have a built a couple myself and the box needs to be big to get both enough speaker volume and the vents in.
No different than positioning a driver, so severely limits usable BW unless phase plugs are used.
The big problem with [relatively] long path FLHs in acoustically small rooms is its 'throw', so better to use the Altec A7 and similar truncated types that only load the mids [~135 Hz/F6] or in medium/large size rooms, my Avatar's A4 [though single cab] or similar system [~70 Hz/F6].
I am researching this now and agree the cabs are best for mid bass. I would love any info relating to this throw. Trying to wrap my mind around the sound wave of a direct radiator compared to that of a horn. I realize "throw" brings up a lot of debate. I read somewhere that the horn's wave is straighter and while you'd think this is a good thing it's not since it much effected my the room modes than direct radiator.
Sam,
Traditionally, "long throw" horns are those with more directionality, a higher DI (Directionality Index). A 60 x 40 degree high frequency horn would have about 3dB forward gain over a 90 x 40, so it was considered to have a longer "throw" given the same power. The ratio of direct to reflected power in a room is also increased by the higher DI horn. That said, the level of each will drop at exactly the same rate on axis, 6dB per doubling of distance in a free field.
In the upper end of "subwoofer" response, 80 to 125 and higher, a large mouth, long path length horn can have a similar increase in DI (+3dB or more on axis) compared to a direct radiator on a smaller baffle.
Tapped Horn Directivity
The room will have less effect on the higher DI upper bass range "punch", while it will still have similar response down low.
The larger radiating area, and two separate point sources in the upper end of a split path "W" bin type of bass horn results in different room modes being excited for the two types of cabinets. A bass horn mouth width (or height) may be 1/2 to near the ceiling height dimension in a small room, so directivity aside, room mode response will be different from a relatively small direct radiator.
As I recall, Hornresp also provides DI patterns, look at them when you post up those sims for the B&C18DS115 compared to the 18SW115 you mentioned posting
.Art