{"id":57,"date":"2011-10-12T15:02:12","date_gmt":"2011-10-12T13:02:12","guid":{"rendered":"http:\/\/localhost\/wordpress\/?page_id=57"},"modified":"2020-11-28T14:45:33","modified_gmt":"2020-11-28T14:45:33","slug":"sequence-two-monitor","status":"publish","type":"page","link":"https:\/\/www.audioexcite.com\/?page_id=57","title":{"rendered":"Sequence Two &#8211; Monitor"},"content":{"rendered":"<h3><span style=\"color: #3366ff;\"><strong>Concept:<\/strong><\/span><\/h3>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/DSC00678.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1794 aligncenter\" title=\"ST-M\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/DSC00678.jpg\" alt=\"\" width=\"168\" height=\"190\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/DSC00678.jpg 298w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/DSC00678-264x300.jpg 264w\" sizes=\"auto, (max-width: 168px) 100vw, 168px\" \/><\/a><\/p>\n<p style=\"text-align: left;\"><strong><span style=\"color: #666699;\">Sequence Two \u2013 Monitor<\/span><\/strong> is a medium sized 2-way stand-mount loudspeaker for small to medium sized listening rooms. There are two different cross-over filter versions, depending on the choice of enclosure design as well as tweeter tuning options.<\/p>\n<h3 style=\"text-align: left;\"><span style=\"color: #3366ff;\">Loudspeaker driver units:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><strong><span style=\"color: #666699;\">Sequence Two \u2013 Monitor<\/span><\/strong> uses a mid-woofer driver unit from AudioTechnology. The 15H520613SDK mid-woofer uses a Kapton voice-coil in order to reproduce a more detailed midrange with higher dynamic and less coloration and distortion. This mid-woofer is one of the very best mid-woofers available to the DIY market. It has not the lowest bass extension, but has a wonderful \u201csnap\u201d and bass articulation together with a remarkable natural mid-range presentation, a class of its own.<\/p>\n<p>The tweeter section consists of the ScanSpeak Illuminator D3004\/660000 textile soft dome tweeter. This is a very low distorting tweeter and it has an extended frequency response in both ends. This tweeter is perfect for designs requiring a low cross-over point or as in this design a low-order cross-over with shallow cross-over slopes.<\/p>\n<p>Sonically it matches the AudioTechnology mid-woofer beautifully and it has a neutral effortless sound characteristic and with great high frequency extension, but without ever sounding exaggerated or harsh.<\/p>\n<p>For further details see:<\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/?page_id=1587\">15H520613SDK<\/a><\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/?page_id=1564\">D3004\/660000<\/a><\/p>\n<h3><span style=\"color: #3366ff;\">Cabinet:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p>The Sequence Two \u2013 Monitor offers two different cross-over filter versions and depending on which of them that are chosen, the following enclosure designs are possible as long as the driver lay-out and baffle size is kept.<\/p>\n<ul>\n<li>5deg backwards slanted baffle for filter v1.0.<\/li>\n<li>The enclosure is tilted back 5deg for filter v1.0.<\/li>\n<li>Use a straight and flat baffle for filter v2.0.<\/li>\n<\/ul>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Baffle-layout.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-1804\" title=\"STM-Baffle layout\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Baffle-layout.jpg\" alt=\"\" width=\"287\" height=\"191\" \/><\/a><\/p>\n<p>In this design I\u2019ve used a 14 liter \u201cDayton Audio\u201d enclosure. This is a very nicely built curved cabinet with a 25mm (1\u2033) MDF front-baffle. The enclosure walls are made of 18mm MDF as well as a 15mm brace from the bottom to the top. The enclosure net volume is around 13 liters (enclosure volume \u2013 drivers, filter and port).<\/p>\n<p>Cabinet drawing: <a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/302-721-dayton-audio-twc-050bk-specifications-459331.pdf\">Dayton 14 liters Curved Cabinet #302-721<\/a><\/p>\n<p>The internal cabinet walls are taped with strings of bitumen pads to reduce resonances. The enclosure is lightly filled with sheep wool. All drivers are flush mount and in order to let the mid-woofer \u201cbreathe\u201d properly, don\u2019t forget to <strong>chamfer<\/strong> the baffle.<\/p>\n<h3><span style=\"color: #3366ff;\">Box simulation:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p style=\"text-align: left;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Cabinet-13liter-45Hz.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1807\" title=\"STM-Cabinet 13liter 45Hz\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Cabinet-13liter-45Hz.jpg\" alt=\"\" width=\"720\" height=\"354\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Cabinet-13liter-45Hz.jpg 1362w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Cabinet-13liter-45Hz-300x147.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Cabinet-13liter-45Hz-1024x503.jpg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/a>~13 liter bass-reflex box with port tuned to 45Hz (anechoic response)<\/p>\n<p>-3db = 46Hz<\/p>\n<p>-6db = 40Hz<\/p>\n<p>-12db = 33Hz<\/p>\n<p>A classic QB3\u00a0 bass-reflex alignment.<\/p>\n<h3><span style=\"color: #3366ff;\">Cross-over design:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><span style=\"color: #666699;\"><strong>The Sequence Two \u2013 Monitor<\/strong><\/span> design offers two different cross-over filter options in order to address the relative acoustic center off-set between the tweeter and the mid-woofer commonly associated with a true symmetrical second-order Linkwitz-Riley (LR2) filter topology.<\/p>\n<p>The most common way to address the driver units relative acoustic center off-set is to use asymmetrical cross-over slopes, but in this design there are two other viable ways to address the off-sets.<\/p>\n<p>Filter <strong>v1.o<\/strong> uses a mechanical way to adjust the off-sets by using a 5deg backwards slanted baffle or by simply tilting the enclosure backwards.<\/p>\n<p>Filter <strong>v2.0<\/strong> uses an electrical way to time delay the tweeter to adjust the acoustical center off-set. This is done by using a \u201cLadder Delay Network\u201d filter circuit, also often called an \u201cAll-pass Network\u201d, \u201cLattice Network\u201d or \u201cPhase Control Circuit\u201d.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Filter v1.0:<\/strong><\/p>\n<p style=\"text-align: left;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1811\" title=\"STM-Filter version 1.0\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0.jpg\" alt=\"\" width=\"720\" height=\"425\" \/><\/a><\/p>\n<p style=\"text-align: left;\">The mid-woofer cross-over filter section is very simple and consists of a large coil (<strong>L1<\/strong>) and a response shaping filter circuit (<strong>C1+L2+R1<\/strong>) that shapes the cross-over slopes to a LR2 roll-off with a targeted 3kHz cross-over point. The large inductor (<strong>L1<\/strong>) tunes the design with a full \u201cBaffle Step Compensation\u201d (BSC).<\/p>\n<p>The tweeter cross-over filter section consists of a single tweeter padding resistor (<strong>R2<\/strong>) and a second-order electrical filter (<strong>C2+L3<\/strong>) that shapes the cross-over slope to a LR2 roll-off with a targeted 3kHz cross-over point. The value of (<strong>R2<\/strong>) can be changed to tailor the tweeter level to personal preferences.<\/p>\n<p style=\"text-align: left;\"><strong>R2<\/strong> = 3.9Ohm -&gt; 0dB (Reference Tweeter Level).<br \/>\n<strong>R2<\/strong> = 4.7Ohm -&gt; -1dB<br \/>\n<strong>R2<\/strong> = 5.6Ohm -&gt; -2dB<\/p>\n<p>(<strong>C3+L4+R3<\/strong>) flattens out the tweeters impedance peak at the resonance frequency and it\u2019s necessary to shape the filter to a LR2 filter slope, as well as to avoid \u201cringing\u201d at the resonance frequency that could cause audible distortion. It\u2019s ok to use a 68uF value for (<strong>C3<\/strong>) when using a high quality component or as in this design combine a cheaper electrolyte cap (68uF) with a high quality 1.0uF cap.<\/p>\n<p>The tweeter is connected with reverse polarity.<\/p>\n<p>(<strong>L5+C4+R4<\/strong>) is a \u201cSystem Impedance Correction Circuit\u201d used to flatten out the impedance when using the loudspeaker with tube amplifiers. It\u2019s optional to use this filter section and it can be omitted when using conventional amplifiers. By using this circuit the impedance is 6 Ohms +\/- 0.5 Ohm within 200-20000Hz.<\/p>\n<p><strong>OBS!<\/strong> When using filter <strong>v1.0<\/strong> you must use a slanted baffle or backwards tilting enclosure in order to get the drivers acoustical center off-sets to match and to get the correct phase tracking around the cross-over frequency. Depending on the listening distance a 5-7deg backwards tilt is adequate.<\/p>\n<p style=\"text-align: left;\"><strong>Filter v2.0:<\/strong><\/p>\n<p style=\"text-align: left;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1815\" title=\"STM-Filter version 2.0\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0.jpg\" alt=\"\" width=\"720\" height=\"425\" \/><\/a>The mid-woofer cross-over filter section is very simple and consists of a large coil (<strong>L1<\/strong>) and a response shaping filter circuit (<strong>C1+L2+R1<\/strong>) that shapes the cross-over slopes to a LR2 roll-off with a targeted 3kHz cross-over point. The large inductor (<strong>L1<\/strong>) tunes the design with a full \u201cBaffle Step Compensation\u201d (BSC).<\/p>\n<p>The tweeter cross-over filter section consists of a single tweeter padding resistor (<strong>R2<\/strong>) and a second-order electrical filter (<strong>C2+L3<\/strong>) that shapes the cross-over slope to a LR2 roll-off with a targeted 3kHz cross-over point. The value of (<strong>R2<\/strong>) can be changed to tailor the tweeter level to personal preferences.<\/p>\n<p style=\"text-align: left;\"><strong>R2<\/strong> = 3.9Ohm -&gt; 0dB (Reference Tweeter Level).<br \/>\n<strong>R2<\/strong> = 4.7Ohm -&gt; -1dB<br \/>\n<strong>R2<\/strong> = 5.6Ohm -&gt; -2dB<\/p>\n<p>(<strong>C5+L6+R3<\/strong>) flattens out the tweeters impedance peak at the resonance frequency and it\u2019s necessary to shape the filter to a LR2 filter slope, as well as to avoid \u201cringing\u201d at the resonance frequency that could cause audible distortion. It\u2019s ok to use a 68uF value for (<strong>C5<\/strong>) when using a high quality component or as in this design combine a cheaper electrolyte cap (68uF) with a high quality 1.0uF cap.<\/p>\n<p style=\"text-align: left;\">(<strong>C3+L4<\/strong> and <strong>C4+L5<\/strong>) contains the \u201cLadder Delay Network\u201d circuit that time delays the tweeter so its acoustic center off-set matches the mid-woofer and makes a perfect phase behavior around the cross-over frequency with minimal phase distortion.<\/p>\n<p style=\"text-align: left;\">The tweeter is connected with reverse polarity and as can been seen in the schematics, the tweeter isn\u2019t connected directly to ground. It\u2019s of the outmost importance that the tweeter is connected exactly as shown, otherwise the delay network will fail.<\/p>\n<p>(<strong>L7+C6+R4<\/strong>) is a \u201cSystem Impedance Correction Circuit\u201d used to flatten out the impedance when using the loudspeaker with tube amplifiers. It\u2019s optional to use this filter section and it can be omitted when using conventional amplifiers. By using this circuit the impedance is 7 Ohms +\/- 1 Ohm within 200-20000Hz.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Cross-over simulation:<\/strong><\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-15deg.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1817 alignnone\" title=\"STM-Filter version 1.0 - sim 15deg\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-15deg.jpg\" alt=\"\" width=\"360\" height=\"279\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-15deg.jpg 982w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-15deg-300x232.jpg 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-15deg.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1818 alignnone\" title=\"STM-Filter version 2.0 - sim 15deg\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-15deg.jpg\" alt=\"\" width=\"360\" height=\"279\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-15deg.jpg 982w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-15deg-300x232.jpg 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-phase.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1819\" title=\"STM-Filter version 1.0 - sim phase\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-phase.jpg\" alt=\"\" width=\"360\" height=\"279\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-phase.jpg 982w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-sim-phase-300x232.jpg 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-phase.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1820\" title=\"STM-Filter version 2.0 - sim phase\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-phase.jpg\" alt=\"\" width=\"360\" height=\"279\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-phase.jpg 982w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-sim-phase-300x232.jpg 300w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><\/p>\n<p><strong>Upper left:<\/strong> Filter <strong>v1.0<\/strong>. Tweeter-axis, 15deg off-axis response.<\/p>\n<p><strong>Upper right:<\/strong> Filter <strong>v2.0<\/strong>. Tweeter-axis, 15deg off-axis response.<\/p>\n<p><strong>Lower left:<\/strong> Filter <strong>v1.0<\/strong>. Individual driver unit phase tracking.<\/p>\n<p><strong>Lower right:<\/strong> Filter <strong>v2.0<\/strong>. Individual driver unit phase tracking.<\/p>\n<h3><span style=\"color: #3366ff;\">Impedance measurements:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-Imp-1L-vs-2R.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1823\" title=\"STM-Filter version 1.0 - Imp 1L vs 2R\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-Imp-1L-vs-2R.jpg\" alt=\"\" width=\"360\" height=\"202\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-Imp-1L-vs-2R.jpg 1366w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-Imp-1L-vs-2R-300x168.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-Imp-1L-vs-2R-1024x575.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-Imp-1L-vs-2R.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1824\" title=\"STM-Filter version 2.0 - Imp 1L vs 2R\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-Imp-1L-vs-2R.jpg\" alt=\"\" width=\"360\" height=\"202\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-Imp-1L-vs-2R.jpg 1366w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-Imp-1L-vs-2R-300x168.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-Imp-1L-vs-2R-1024x575.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><\/p>\n<p><strong>Left:<\/strong> Filter version <strong>v1.0<\/strong>. Blue=Left loudspeaker, Green=Right loudspeaker.<\/p>\n<p><strong>Right:<\/strong> Filter version <strong>v2.0<\/strong>. Blue=Left loudspeaker, Green=Right loudspeaker.<\/p>\n<p>Overall an easy load for the amplifier. Nice consistency between left and right loudspeaker.<\/p>\n<h3><span style=\"color: #3366ff;\">Frequency measurements:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p>If nothing else is noted in the comments, the following frequency measurements of the finished loudspeaker are made at a 2m distance at tweeter height and for the 0db tweeter reference level.<\/p>\n<p>All frequency response charts are presented in a 50db scale with 1\/24 octave smoothing and the measurements are valid down to 350Hz.<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-15deg-v1.0-vs-v2.0-ref-tw.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1826\" title=\"STM-15deg v1.0 vs v2.0 ref tw\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-15deg-v1.0-vs-v2.0-ref-tw.jpg\" alt=\"\" width=\"720\" height=\"243\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-15deg-v1.0-vs-v2.0-ref-tw.jpg 1117w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-15deg-v1.0-vs-v2.0-ref-tw-300x101.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-15deg-v1.0-vs-v2.0-ref-tw-1024x345.jpg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/a><strong>Frequency response 15deg off-axis, reference tweeter level:<\/strong><\/p>\n<p style=\"text-align: left;\"><strong>Blue:<\/strong> Filter <strong>v1.0<\/strong><\/p>\n<p style=\"text-align: left;\"><strong>Red:<\/strong> Filter <strong>v2.0<\/strong><\/p>\n<p>Very similar frequency response behavior between the two cross-over filter versions. Slightly higher level around 4kHz for the filter <strong>v2.0<\/strong>.<\/p>\n<p style=\"text-align: left;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-0-22.5deg-ref-tw.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1827\" title=\"STM-Filter version 1.0 - 0-22.5deg ref tw\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-0-22.5deg-ref-tw.jpg\" alt=\"\" width=\"360\" height=\"122\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-0-22.5deg-ref-tw.jpg 1117w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-0-22.5deg-ref-tw-300x101.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-0-22.5deg-ref-tw-1024x345.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-0-22.5deg-ref-tw.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1828\" title=\"STM-Filter version 2.0 - 0-22.5deg ref tw\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-0-22.5deg-ref-tw.jpg\" alt=\"\" width=\"360\" height=\"122\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-0-22.5deg-ref-tw.jpg 1117w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-0-22.5deg-ref-tw-300x101.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-0-22.5deg-ref-tw-1024x345.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><\/p>\n<p style=\"text-align: left;\"><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-30-60deg-ref-tw.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1829\" title=\"STM-Filter version 1.0 - 30-60deg ref tw\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-30-60deg-ref-tw.jpg\" alt=\"\" width=\"360\" height=\"122\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-30-60deg-ref-tw.jpg 1117w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-30-60deg-ref-tw-300x101.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-30-60deg-ref-tw-1024x345.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-30-60deg-ref-tw.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1830\" title=\"STM-Filter version 2.0 - 30-60deg ref tw\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-30-60deg-ref-tw.jpg\" alt=\"\" width=\"360\" height=\"122\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-30-60deg-ref-tw.jpg 1117w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-30-60deg-ref-tw-300x101.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-30-60deg-ref-tw-1024x345.jpg 1024w\" sizes=\"auto, (max-width: 360px) 100vw, 360px\" \/><\/a><\/p>\n<p style=\"text-align: left;\"><strong>Upper left:<\/strong> Filter <strong>v1.0<\/strong>. Tweeter-axis @ 2m, 0, 15 and 22.5deg off-axis.<\/p>\n<p style=\"text-align: left;\"><strong>Upper right:<\/strong> Filter <strong>v2.0<\/strong>. Tweeter-axis @ 2m, 0, 15 and 22.5deg off-axis.<\/p>\n<p style=\"text-align: left;\"><strong>Lower left:<\/strong> Filter <strong>v1.0<\/strong>. Tweeter-axis @ 2m, 30, 45 and 60deg off-axis.<\/p>\n<p style=\"text-align: left;\"><strong>Lower right:<\/strong> Filter <strong>v2.0<\/strong>. Tweeter-axis @ 2m, 30, 45 and 60deg off-axis.<\/p>\n<h3 style=\"text-align: left;\"><span style=\"color: #3366ff;\">Distortion measurement:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><strong>Measurement setup:<\/strong><\/p>\n<ul>\n<li>\u00a0\u00a0\u00a0 Tweeter-axis near-field measurement at 20cm<\/li>\n<li>\u00a0\u00a0\u00a0 Frequency Range: 200-10000Hz<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>The distortion measurements are done in near-field and the amplifier output level was adjusted for the loudspeaker so that the fundamental is 85dB at 1m and 90dB at 1m. This setting simulates normal to medium-high listening levels.<\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-dist-85dB.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1833\" title=\"STM-Filter version 1.0 - dist 85dB\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-dist-85dB.jpg\" alt=\"\" width=\"360\" height=\"205\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-dist-90dB.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1834\" title=\"STM-Filter version 1.0 - dist 90dB\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-dist-90dB.jpg\" alt=\"\" width=\"360\" height=\"205\" \/><\/a><\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-dist-85dB.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1835\" title=\"STM-Filter version 2.0 - dist 85dB\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-dist-85dB.jpg\" alt=\"\" width=\"360\" height=\"205\" \/><\/a><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-dist-90dB.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1836\" title=\"STM-Filter version 2.0 - dist 90dB\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-dist-90dB.jpg\" alt=\"\" width=\"360\" height=\"205\" \/><\/a><\/p>\n<p><strong>Upper left:<\/strong> Filter <strong>v1.0<\/strong>, 85dB @ 1m<\/p>\n<p><strong>Upper right:<\/strong> Filter <strong>v1.0<\/strong>, 90dB @ 1m<\/p>\n<p><strong>Lower left:<\/strong> Filter <strong>v2.0<\/strong>, 85dB @ 1m<\/p>\n<p><strong>Lower right:<\/strong> Filter<strong> v2.0<\/strong>, 90dB @ 1m<\/p>\n<p>Overall a very low distortion loudspeaker. The only thing that smudges the measurements is the cone-edge resonance at 1.25kHz that contributes to an elevated, but sonically harmless second-order harmonics.<\/p>\n<h3><span style=\"color: #3366ff;\">Component list:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p>Filter<strong> v1.0<\/strong>:<\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-component-list-.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1838\" title=\"STM-Filter version 1.0 - component list\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-component-list-.jpg\" alt=\"\" width=\"720\" height=\"606\" srcset=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-component-list-.jpg 1215w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-component-list--300x253.jpg 300w, https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-1.0-component-list--1024x863.jpg 1024w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>Filter <strong>v2.0<\/strong>.<\/p>\n<p><a href=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-component-list-.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1839\" title=\"STM-Filter version 2.0 - component list\" src=\"https:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/STM-Filter-version-2.0-component-list-.jpg\" alt=\"\" width=\"720\" height=\"606\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>At 1600 US$ a pair this DIY loudspeaker is quite expensive, but the cost can be reduced by choosing less expensive cross-over components and by building your own enclosures.<\/p>\n<p>However I strongly advice to use the suggested cross-over component quality because it gives a very noticeable sound quality boost together with these two very fine loudspeaker drivers.<\/p>\n<h3><span style=\"color: #3366ff;\">\u00a0Summary:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><strong>Sound description:<\/strong><\/p>\n<p>Even though this loudspeaker is an expensive DIY design it easily outperforms similar loudspeakers costing at least 2-3 times more. It\u2019s a big investment, but well worth it.<\/p>\n<p>I\u2019m not a huge fan of over complex cross-over filters, but in this case the filter v2.0 gives less phase distortion and has some more \u201cpresence\u201d in its character. The v1.0 filter is tonally a bit more laid-back in its reproduction. Both versions are very good and which one to choose is more a matter of personal taste.<\/p>\n<p>When comparing this loudspeaker with the Revelation Two \u2013 Monitor it doesn\u2019t dig as deep in the low bass, but what it lacks in the lowest bass it exceeds in speed and micro articulation.<\/p>\n<p>The midrange is clean, neutral and is effortless in its character. The reproduction of voices is very realistic and natural.<\/p>\n<p>The tweeter is well extended and neutral in its character.\u00a0 It never sounds harsh, exaggerated or tries to draw your attention from the music. The tweeter works in perfect harmony with the neutral and effortless character of the mid-woofer and they are a perfect match to each other.<\/p>\n<p>The loudspeaker has a very generous sound stage with a nice width, height and depth.<\/p>\n<p>When you close your eyes and listen you can easily hear the location of the individual instruments and musicians in the recording.<\/p>\n<p>With a well-made recording you are rewarded with a huge crisp soundstage. Less good recordings are still enjoyable, since the loudspeaker is forgiving and non-analytic in its character, but at the very same time very detailed.<\/p>\n<p>It\u2019s the marvelous mid-range reproduction that really makes this loudspeaker shine. AudioTechnology have succeeded to build a mid-woofer that can combine micro detail and speed, but without ever sounding could or analytic, together with a very convincing and natural voice reproduction.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Recommended loudspeaker placement:<\/strong><\/p>\n<ul>\n<li>\u00a0\u00a0\u00a0 No or little toe-in.<\/li>\n<li>\u00a0\u00a0\u00a0 &gt;0.5 meters from back wall.<\/li>\n<li>\u00a0\u00a0\u00a0 2-3 meters apart.<\/li>\n<li>\u00a0\u00a0\u00a0 2.5-3 meters listening distance<\/li>\n<\/ul>\n<p>The loudspeaker is optimized for a listening distance of 2.5m, but everything between 2-3.5m works fine. As always it pays off to test different loudspeaker placements and see what fits the room and personal preferences the best.<\/p>\n<h3><span style=\"color: #3366ff;\">Technical Specification:<\/span><\/h3>\n<p>&nbsp;<\/p>\n<p><span style=\"color: #666699;\"><strong>Sequence Two \u2013 Monitor<\/strong><\/span><br \/>\n<strong>Type:<\/strong> Two-way medium sized stand-mount loudspeaker<br \/>\n<strong>Enclosure type:<\/strong> Bass-reflex<br \/>\n<strong>Woofer driver unit:<\/strong> 5,5\u201d Polypropylene cone. AudioTechnology 15H520613SDK<br \/>\n<strong>Tweeter driver unit:<\/strong> 1.1\u201d Textile soft dome ScanSpeak D3004\/660000<br \/>\n<strong>Cross-over frequency:<\/strong> Filter v1.0 3kHz, filter v2.0 2.8kHz.<br \/>\n<strong>Cross-over function:<\/strong> LR second-order acoustically, first-order electrically (wo) and second-order electrically (tw)<br \/>\n<strong>Frequency response:<\/strong> 40-20000Hz -6\/+0 db (on-axis)<br \/>\n<strong>Sensitivity:<\/strong> 85db 1m\/2.83v<br \/>\n<strong>Impedance:<\/strong> 8 Ohm<br \/>\n<strong>Enclosure volume:<\/strong> 13 liter internal net volume<br \/>\n<strong>Weight:<\/strong> 11kg (24,25lb)<br \/>\n<strong>Enclosure dimensions:<\/strong> (height x width x depth): 356x216x317mm (14\u2033x8.5\u2033x12.5\u2033)<\/p>\n<h3><\/h3>\n<p>&nbsp;<\/p>\n<p>I&#8217;m happy to accept any kind of donations!<\/p>\n<p>Thank you!<\/p>\n<p><em>\/G\u00f6ran<\/em><\/p>\n<p><em>Author of the &#8220;AudioExcite Loudspeaker Design&#8221; website<\/em><\/p>\n<form id=\"donateplusform\" action=\"https:\/\/www.paypal.com\/cgi-bin\/webscr\" method=\"post\"><input type=\"hidden\" id=\"cmd\" name=\"cmd\" value=\"_donations\">\n\t\t\t<p class=\"donate_amount\"><label for=\"amount\">Donation Amount:<\/label><br \/><input type=\"text\" name=\"amount\" id=\"amount\" value=\"0\" \/> <small>(Currency: EUR)<\/small><\/p>\n<input type=\"hidden\" name=\"notify_url\" value=\"https:\/\/www.audioexcite.com\/wp-content\/plugins\/donate-plus\/paypal.php\">\n<input type=\"hidden\" name=\"item_name\" value=\"Donation to AudioExcite\">\n<input type=\"hidden\" name=\"business\" value=\"info@audioexcite.com\">\n<input type=\"hidden\" name=\"lc\" value=\"US\">\n<input type=\"hidden\" name=\"no_note\" value=\"1\">\n<input type=\"hidden\" name=\"no_shipping\" value=\"1\">\n<input type=\"hidden\" name=\"rm\" value=\"1\">\n<input type=\"hidden\" name=\"return\" value=\"https:\/\/www.audioexcite.com\/?page_id=587&amp;thankyou=true\">\n<input type=\"hidden\" name=\"currency_code\" value=\"EUR\">\n<input type=\"hidden\" name=\"bn\" value=\"PP-DonationsBF:btn_donateCC_LG.gif:NonHosted\">\n<p class=\"submit\"><input type=\"image\" src=\"http:\/\/www.audioexcite.com\/wp-content\/uploads\/2011\/10\/paypal-donate.gif\" border=\"0\" name=\"submit\" alt=\"\">\n<img loading=\"lazy\" decoding=\"async\" alt=\"\" border=\"0\" src=\"https:\/\/www.paypal.com\/en_US\/i\/scr\/pixel.gif\" width=\"1\" height=\"1\"><\/p>\n<\/form>\n","protected":false},"excerpt":{"rendered":"<p>Concept: &nbsp; Sequence Two \u2013 Monitor is a medium sized 2-way stand-mount loudspeaker for small to medium sized listening rooms. There are two different cross-over filter versions, depending on the choice of enclosure design as well as tweeter tuning options. Loudspeaker driver units: &nbsp; Sequence Two \u2013 Monitor uses a mid-woofer driver unit from AudioTechnology. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":34,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-57","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/57","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=57"}],"version-history":[{"count":38,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/57\/revisions"}],"predecessor-version":[{"id":1795,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/57\/revisions\/1795"}],"up":[{"embeddable":true,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/34"}],"wp:attachment":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=57"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}