ATH M40X Modifications

Audio Technica ATH-M40X

Waterfall (CSD) L + R re!uenc" #lot$ Left% Ri&ht The ATH-40X ATH-40X i' the chea#er ( 00*-) rother of the M,0(X)* t differ' ./R 1uch fro1 the ATH-M40f' ATH-M40f' in loo2'% co1fort% 'i3e and aoe all 'ound* 5elo6 the fre!uenc" #lot of the ATH-M40X* ATH-M40X* There 'ee1' to e a little !ualit" control 7 1atchin& i''ue &oin& on here*  1ea'ured it 'eeral ti1e' and in 'eeral #o'ition' and een reer'ed it on the te't ri& and the ('u'tantial) difference et6een L and R i' reall" #re'ent* 4 d5 difference in the 00H3-400H3 re&ion i' a it 'tran&e* Accordin& to 'o1e reie6' and Audio Technica Technica thi' head#hone i' 8flatter 9 than the M,0X and indeed it 'ound' 8flatter9 than the M,0X ut 'till ha' 8i&9 a''* :er'onall"  li2e a it of a'' 'o don9t 1ind it  there 6eren9t that 1uch difference et6een L and R* :roduct ariance or i''ue ; The head#hone 'ound' etter than it 1ea'ure' and ha' a ( 'o1e6hat fatt" and eleated) a'' ut no 86ar19 'ound* Thi' i' cau'ed " the 8di#9 et6een <00H3 and 2H3* Thi' &ie' oice' a 8clear9 'ound and ecau'e the R dro#' off aoe <2H3 there i' no 8'hrill9 'ound* The hi&h' are 8clear9 and 'oft ut the 8detail'9 (the #art aoe 02H3) i' eleated too 1uch ut not anno"in&l" hi&h* The oerall 'ound i' 8&ood9 aleit a it on the a''" 'ide and the trele i' '1ooth ut a it 8artificial9* The CSD (Waterfall #lot) 'ho6' 'o1e 'hort lied re'onance' around 42H3% =2H3 and >2H3* ?o i dea if it i' a coincidence ut the'e' fre!uencie' are har1onic'* ?o deal rea2in& lon& lied re'onance' ut al'o no re1ar2ale #erfor1ance* Ti1e to e@#eri1ent 6ith #ad'% felt% 6ool% filter' and other 1odification'*

What' i11ediatel" a##arent i' the difference et6een L and R drier et6een 00H3 and ,00H3* The onl" oiou' difference et6een L and R cu#' i' the #re'ence of the head#hone 'oc2et in'ide the cu#* Al'o it could e ('1all) difference in the cu# olu1e ut 4d5 i' a it 1uch for thi'*  o#ened the head#hone and on the in'ide coered the 'oc2et 6ith 1alleale era'er to 'eal an" lea2'* ?B difference in R* 'toc2% 'oc2et 'ealed 6ith era'er

?e@t  o#ened u# the ri&th cu# and #laced a lu1# of 1alleale era'er in it of the 'a1e 'i3e a' the connector* ?o difference in R (?BT/$ R li1ited to ,2H3 in thi' #lot)* ?e@t atte1#t i' " 'tuffin& the cu# (the Left channel) 6ith den'el" #ac2ed 'hee# 6ool* A&ain% ?B difference in R* The '1all difference et6een ,2 and =2 could #oint to reflection' ein& da1#ed etter* t certainl" didnt chan&e the a'' (6hich  ho#ed it  6ould do)* There 'ee1' no effect in the lo6' the rea'on for thi' 1a" e that the cu#' are co1#letel" clo'ed* S6a##in& #ad' L and R did not do an"thin&* What effect do the ent' in the cu#' hae ; Stoc2% .ent' loc2ed fro1 the in'ide 6ith 1alleale era'er* t 'ee1' to hae an i1#act et6een 2H3 and 42H3* The 'har# di# at =2H3 could al'o e cau'ed " incorrect #o'itionin&% the -4 2H3 chan&e cannot* nderneath the #ad' there i' an acou'tic tran'#arent foa1 6hich lift' the #ad' a it* Thi' enale' the 'ound to #a'' throu&h the ent' underneath the #ad' and 1a2e it into the ear cha1er*

'toc2% foa1 under #ad' re1oed

'toc2% a doule la"er of foa1 under the #ad'

Re1oin& the foa1 ncrea'ed the lo6er 1id'% a doule la"er decrea'ed the lo6er and u##er 1id'*

The to# and (aoe 02H3) i' &iin& a fa2e 'en'e of detail' and the 'hi11er off c"1al' and iolin' &et' a 'li&htl" artificial and unnatural effect*

'toc2% 6ith <11 felt in front of the drier

'toc2% 6ith electronic filter*

The felt lo6er' the 02H3 #ea2 and doe' not chan&e the R u# to ,2H3* The 'ide effect' are the di# in R around *,2H3% (1ea'ured it a cou#le of ti1e') and doe'nt lo6er the ,2H3 #ea2*

The electronic filter ('ho6n on the ri&ht) lo6er' the a'' and addre''e' the #ea2' onl"* The head#hone 'ound' 1ore natural*

:ad' hae a #rofound i1#act on the 'ound* 5elo6 'o1e e@#eri1ent' 6ith different #ad' (left channel)

'toc2 #ad'% Ta'ca1 TH-0< #ad'

'toc2 #ad'% o'te@ T,0R: #ad'

'toc2 #ad'% 5e"erd"na1ic DT0 #ad'

'toc2 #ad'% Shure SRH-=40 #ad'

'toc2 #ad'% Shure SRH-E40 elour #ad'

'toc2 #ad'% SRH-E40 #ad' + <11 felt

The Shure SRH-E40 #ad' 'ee1 to #erfor1 6ell 6hen the #ea2 i' lo6ered u'in& a <11 thic2 felt* The 'onic 'i&nature i' !uite flat ri&ht do6n to 40H3 and e@tend' e"ond <02H3* There i' a di# around F*,2H3 ut thi' i' #re'ent in a lot of head#hone' and not a' anno"in& a' di#' in other fre!uenc" and'* Re'ult' of thi' 1echanical7acou'tical 1odification i' 'ho6n elo6 ( ri&ht% left)

Result:

< 6a"' to 1odif" the ATH-M40X

keep it stock and use the electronic filter (doesn't change the L-R differences). B: Use SRH-940 pads and !! thick felt in front of the dri"er. A' a onu'% and oddl" enou&h% the L-R difference 'ee1' to e 1uch '1aller a' 6ell* A:

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