{"id":5529,"date":"2015-08-15T16:40:54","date_gmt":"2015-08-15T16:40:54","guid":{"rendered":"http:\/\/www.audioexcite.com\/?page_id=5529"},"modified":"2016-12-05T18:54:54","modified_gmt":"2016-12-05T18:54:54","slug":"nht-2-5i-review-part-5","status":"publish","type":"page","link":"https:\/\/www.audioexcite.com\/?page_id=5529","title":{"rendered":"NHT 2.5i review part 5"},"content":{"rendered":"

 <\/p>\n

Part 5 of the NHT 2.5i review contains the system impedance and frequency measurements as well as a frequency measurements analysis on the effects of using the tweeter foam pad.<\/p>\n

System impedance:<\/span><\/h3>\n

 <\/p>\n

\"Imp<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Blue:<\/strong> Left loudspeaker<\/p>\n

Red:<\/strong> Right Loudspeaker<\/p>\n

System impedance minimum of 3.4 Ohm @ 80Hz, which is slightly lower than the specified 3.6 Ohm.<\/p>\n

System frequency:<\/span><\/h3>\n

 <\/p>\n

If nothing else is noted in the comments, the following frequency measurements of the NHT 2.5i loudspeaker are made at a 2m distance at mid-woofer height.<\/p>\n

All frequency response charts are presented in a 50db scale with 1\/24 octave smoothing and the measurements are valid down to 375Hz.<\/p>\n

\"Freq<\/a>\"Freq<\/a><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Frequency response on-axis:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Frequency response 15deg off-axis:<\/strong><\/p>\n

Blue:<\/strong>\u00a0<\/span>Left Loudspeaker @ 2m<\/p>\n

Red:<\/strong>\u00a0<\/span>Right Loudspeaker @ 2m<\/p>\n

\"Freq<\/a>\"Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Left:<\/strong> On-axis, 15 and 21deg off-axis @ 2m<\/p>\n

Right:<\/strong> 30, 45 and 60deg off-axis @ 2m<\/p>\n

For a commercial design, the NHT 2.5i loudspeaker has a very linear frequency response. The tweeter dome break-up @ 26kHz is well suppressed by the tweeter dome diffuser.<\/p>\n

Frequency 10cm above the mid-woofer:<\/span><\/h3>\n

 <\/p>\n

\"Freq<\/a>\"Freq<\/a><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Frequency response on-axis:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Frequency response 15deg off-axis:<\/strong><\/p>\n

Blue:<\/strong> Mid-woofer height @ 2m<\/p>\n

Red:<\/strong> 10cm above mid-woofer height @ 2m<\/p>\n

\"Freq<\/a>\"Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Left:<\/strong> 10cm above mid-woofer, on-axis, 15 and 21deg off-axis @ 2m<\/p>\n

Right:<\/strong> 10cm above mid-woofer, 30, 45 and 60deg off-axis @ 2m<\/p>\n

The frequency response at the normal listening height (10cm above mid-woofer).<\/p>\n

Frequency with and without tweeter foam pad:<\/span><\/h3>\n

 <\/p>\n

\"\"<\/a>\"\"<\/a>\"\"<\/a><\/p>\n

Left:<\/strong> Rotten foam pad.<\/p>\n

Middle:<\/strong> Foam pad removed.<\/p>\n

Right:<\/strong> New foam pad.<\/p>\n

1m frequency measurements of the NHT 2.5i tweeter made at mid-woofer height.<\/p>\n

\"Freq<\/a>\"Freq<\/a>
\n\"Freq<\/a>\"Freq<\/a><\/p>\n

(click on picture to zoom)<\/p>\n

Top left:<\/strong> On-axis, foam pad (blue) vs no foam pad (red)
\nTop right:<\/strong> 15deg off-axis, foam pad (blue) vs no foam pad (red)
\nLower left:<\/strong> 21deg off-axis, foam pad (blue) vs no foam pad (red)
\nLower right:<\/strong> 30deg off-axis, foam pad (blue) vs no foam pad (red)<\/p>\n

There is very little difference using the foam pad or not. First at a 30deg off-axis angle we can see some difference.<\/p>\n

Most of the baffle diffraction is already reduced by off-set mounting the tweeter on the baffle. Actually, even the mid-woofer is slightly off-set mounted by about 2mm, but this is made in order to make it fit inside of the angled enclosure.<\/p>\n

End of review part 5!<\/p>\n

Go to NHT 2.5i review part 6<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

  Part 5 of the NHT 2.5i review contains the system impedance and frequency measurements as well as a frequency measurements analysis on the effects of using the tweeter foam pad. System impedance:   (click on picture to zoom) Blue: Left loudspeaker Red: Right Loudspeaker System impedance minimum of 3.4 Ohm @ 80Hz, which is […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-5529","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/5529","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=5529"}],"version-history":[{"count":10,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/5529\/revisions"}],"predecessor-version":[{"id":6045,"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=\/wp\/v2\/pages\/5529\/revisions\/6045"}],"wp:attachment":[{"href":"https:\/\/www.audioexcite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5529"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}