In the last issue of Guangzhou Redco Audio's home theater audio-visual room, I focused on two built-in active subwoofers from JL Audio. Truly! The 8 subwoofers have a good sense of bass envelopment, and the subwoofer is installed on the top, which is a correct way to reproduce the bass information that originally came from above. In addition to the 8 subwoofers, the other 21 speakers all use ATC products. ATC is a widely recognized brand in the audiophile circle and even among professional audio workers (including me), and there is no one who does not know ATC. Audiophiles often apply ATC speakers to two-channel audio, but in fact, the effect of applying them in home theaters is also very good, especially in the three-dimensional immersive sound home theater composed of 21ATC speakers, the sound is as if you are surrounded by the live version, so the focus this time is these 21ATC speakers. 
Five front-channel speaker configurations
I opened one of the pieces of acoustic material, drilled behind the projection screen, and found that there were 8 speakers in this section. Among them, there are 5 loudspeakers on the horizontal level, all of which use HTS40 loudspeakers. Among them, 3 HTS40 are placed behind the screen, that is, the left, middle and right channel speakers in front, and the other 2 HTS40 are placed on both sides of the screen, which are used as left and right widening channels, so that the horizontal coverage of the sound is larger, creating a wider sound field effect.
Three HTS40s are positioned behind the screen as center channel speakers
Pay attention to a detail on the right side of the HTS40 speaker midrange, in fact, the HTS40 tweeter can be adjusted according to the placement requirements, which is very flexibleThree-way design, ATC's signature "steamed bun" midrange driverThe SCM40 loudspeakers are a three-way design, and in the midrange section, they all use ATC's signature dome tweeter, commonly known as the "Mantou" midrange unit. ATC's full name is Acoustic Transducer Company, which literally means a company that designs and manufactures loudspeakers (electroacoustic transducers). ATC's earliest products were drivers, and then it was further developed into professional recording studios, post-production rooms, and professional monitors, and then developed into home audio. Whether it is a home audio or a professional audio, ATC's pursuit of sound reproduction is the same, requiring the ability to reproduce real, natural, and smooth sound. In other words, with ATC speakers at home, you can also get close to studio sound effects. The "Mantou" midrange unit is one of ATC's proud works. Because the performance is so good, some audio manufacturers go back to design speakers from ATC purchase units. For example, companies such as Proac, PMC, and Genelec have also been users of ATC units. The biggest feature of ATC's "Mantou" midrange is the wide replay frequency response. The model of the Mantou midrange unit used in HTS40 is SM75-150, which is responsible for 380Hz 35khz。To put it in layman's terms, "from medium and high frequency to medium and low frequency", the most commonly heard sound frequency by the human ear is concentrated in this range, this frequency range is not "cut" by the crossover, and another feature of this unit is low distortion, so the midrange of ATC sounds natural and smooth, and the amount of information is large, which is the charm of ATC. The woofer is a 164mm long-excursion low-distortion woofer, this unit is a long magnetic gap, short voice coil design, the advantages are twofold, first: it can better ensure that the voice coil is in the linear area of the magnetic gap; Second: long strokes can be achieved. In addition, there is a special coating on the surface of the cone that suppresses split vibrations, and even if the woofer is not large, it can produce strong, fast, high-quality bass. As for the tweeter being a 25mm neodymium dome tweeter, the design of this tweeter is even more exaggerated. First of all, it is a double overhang design, and secondly, it has a strong magnetic field, and the magnetic field strength of the magnetic circuit is up to 15000 gauss. This is designed for one purpose in mind, with low distortion at high sound pressure outputs. Here is a brief summary. The front main channel is responsible for a large amount of sound information in the surround sound effect**,HTS40 is designed with large sound pressure output in mind,And the nominal maximum sound pressure level is112dB,At the same time, it also has the "monitoring" characteristics in terms of sound, which fully meets the performance requirements of the home theater main channel speaker. 
The left and right channel speakers use SCM40 floorstanding speakersDolby Atmos, DTS:X, and AURO-3D layouts are supportedThe speaker layout of this AV room is designed to accommodate Dolby ATMOS, DTS:X and AURO-3D. There is a pre-booster channel directly above the front channel, and 3 HTS11Cs are used in this part, which is the pre-booster channel of AURO-3D. Looking at the sky channel part, HTS11 is used here, and there are a total of 7 speakers here. One of them is the voice of gods channel of AURO-3D, and the other 6 speakers are front, middle, and rear 3 pairs of sky channel speakers. There are also two sides,The rear surround sound speaker isHTS11,A total of 4,As for the rear elevated channel, 2HTS11C is used。 That's 21 speakers, plus 8 subwoofers it's 21With 8 configurations, a total of 29 speakers, the Stormaudio ISP MK2, a surround sound processor with a maximum output of 32 channels, is fully sufficient. HTS11 and HTS11C are portrait and landscape versions, respectively. They are the same except for the different shapes, and the purpose is to let the user choose according to the installation environment. ATC's official recommendation for the use of HTS11 and HTS11C is that it is suitable for surround channel and sky channel use in large rooms, and can also be used as main channel speakers in small rooms. The tweeter of HTS11 and HTS11C is the same as HTS40 with a 25mm neodymium dome tweeter, while the diameter of the mid-woofer is 150mm, the voice coil of this unit reaches 45mm, and the magnet is also oversized, close to the diameter of the cone. In addition, the cones are equipped with CLD (Constrained Layer Damping) technology. Roughly speaking, its sound cone is a three-layer structure, and there is a damping layer in the middle of the front and rear cones, which is used to suppress the split vibration and improve harmonic distortion. 
The white speaker is HTS11, which is the rear surround channel, and the black speaker is HTS11C, which is the rear booster channel
The difference between HTS11C and HTS11 is that the shape is different, it belongs to the horizontal version of HTS11, and there is no difference in other aspectsEnjoy the multi-channel** as if you were in the sceneI watched "Quincy Jones - Live at Montreux 2008" Blu-ray disc, although it was 51-channel DTS-HD Master Audio, but the recording effect is very good, and it is also good to listen to it after Storm Audio's internal upmixing function becomes a Atmos output. I listened to the singer's rendition of "Bille Jean" with **, and the pure vocal interpretation can well reflect the advantages of ATC in vocals, the vocal voice is very informative, the sound density is large, and the clarity is high, and you can even judge the positioning differences between different vocals. As for "feel like **live!".Jazz Blu-ray Disc, the focus of this Blu-ray disc, which offers both Dolby Atmos and Auro-3D soundtracks. In this audition, I compared the two and felt that the sound of the AURO-3D track was warmer and fuller. Of course, the effect of ATC speakers is needless to say,**The rhythm is relaxed, bright, the timbre is natural, and the positioning of the instrument is clear. Not only that, but the three-dimensional immersive sound effect used in the production can also present a very wide sound field effect, to what extent? The width of the sound field created by the surround sound system is larger than the width of the projection screen. But if you close your eyes and feel it with your ears alone, you'll feel as if you're there. But if you want to be real, if you want to say that you are in the scene, the *** Magnificat launched by 2L Company is very good. It offers 91-channel three-dimensional immersive sound format, and it is pure audio, and the sound quality is very good. The recording location of this ** is selected in the church, the reverberation sound effect of the church itself is very well recorded, the reverberation sound is very rich, the sense of scene is strong, and I can clearly distinguish in the replay of the sound system that the sound image positioning of the vocal choir is slightly higher than that of the instrument, especially when the choir sings in unison, the sense of scale of the sound field is really large, the sense of space is really open, and the feeling of restoring multi-channel with multi-channel sound is completely different.
Summary. Durable and comfortable, delicate and dense.
ATC's speaker also has a feature,It is not like modern speakers to pursue bright,Vivid sound presentation,On the contrary, it is restrained,Unassuming,A comfortable and durable sound in the sense of hearing,This aspect is mainly reflected in the treble part。 Some consumers feel that "the effect is too exciting, it doesn't sound very comfortable, and the ears feel tired" when experiencing home theater. To put it bluntly, the treble is too much, and even the distortion is too large. But there will be no problem in ATC speakers,Even you will feel that these stimulating sound effects sound just right in ATC speakers,On the one hand, it is its tuning orientation,On the other hand, its treble distortion is low,Smooth and smooth hearing,You won't feel tired when listening to your ears for a long time。 The sound of the ATC speaker is not only durable,And the amount of sound information in the midrange is really good,The sound is delicate and dense,Very natural presentation,The expansion of the sound field is good。 I once had the experience of listening to the final production sound effects in the post-production studio, and the listening experience in the post-production room was not exciting, but smooth and natural, the amount of sound information was very rich, and the density was high.
Reference**: ATC HTS40 (3, used in the middle channel), reference**36800 yuan only ATC HTS11 (14, front heightening, surround and sky channel use), reference**13800 ATC HTS11C (2, rear increase channel use), reference**13800 yuan.