diff --git a/src/mame/drivers/namcos11.c b/src/mame/drivers/namcos11.c
index 27eda514ecd..7a7b4ba0d2a 100644
--- a/src/mame/drivers/namcos11.c
+++ b/src/mame/drivers/namcos11.c
@@ -996,9 +996,8 @@ static MACHINE_CONFIG_START( coh100, namcos11_state )
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8538Q, 0x200000, XTAL_53_693175MHz )
 
 	MCFG_SPEAKER_STANDARD_STEREO("lspeaker", "rspeaker")
-	// note: C352 internal divider is currently set to 288, but that sounds wrong with an input clock of 20MHz.
-	// 228.0 here is a guess, estimated from PCB recordings sound/music pitch.
-	MCFG_C352_ADD("c352", 20000000 / (228.0/288.0))
+
+	MCFG_C352_ADD("c352", 16934400*1.5) // measured at 20MHz, but that's too lowpitched
 	MCFG_SOUND_ROUTE(0, "rspeaker", 1.00)
 	MCFG_SOUND_ROUTE(1, "lspeaker", 1.00)
 	MCFG_SOUND_ROUTE(2, "rspeaker", 1.00)
diff --git a/src/mame/drivers/namcos12.c b/src/mame/drivers/namcos12.c
index 05947145048..50dfdc037a7 100644
--- a/src/mame/drivers/namcos12.c
+++ b/src/mame/drivers/namcos12.c
@@ -201,13 +201,13 @@ Notes:
       6734         : MAX734 +12V 120mA Flash Memory Programming Supply Switching Regulator (SOIC8)
       3414A        : NJM3414A 70mA Dual Op Amp (SOIC8)
       LC78832M     : Sanyo LM78832M 2-Channel 16-Bit D/A Converter LSI with 2 On-Chip Digital Filters (SOIC20)
-      2061ASC-1    : IC Designs 2061ASC-1 Programmable Clock Generator (SOIC16)
+      2061ASC-1    : IC Designs 2061ASC-1 Programmable Clock Generator (SOIC16), master input of 14.7456MHz
       R4543        : EPSON Real Time Clock Module (SOIC14)
       DSW(2)       : 2-Position DIP Switch (All OFF)
       N341256      : NKK N341256 32k x8 SRAM (x2, SOJ28)
       H8/3002      : Sound CPU, Hitachi H8/3002 HD6413002F17 (QFP100), clocked at 16.737MHz
       C416         : Namco custom C416 (QFP176)
-      C352         : Namco custom C352 PCM sound chip (QFP100)
+      C352         : Namco custom C352 PCM sound chip (QFP100), clocked at 29.168MHz, from 2061 pin 9
       MOT1         : PALCE 22V10H (PLCC28, labelled 'S12MOT1A')
                      *Replaced by PALCE 22V10H (PLCC28, labelled 'S12MOT1C') on MOTHER (C) PCB
       MOT2         : PALCE 22V10H (PLCC28, labelled 'S12MOT2A')
@@ -1672,7 +1672,7 @@ static MACHINE_CONFIG_START( coh700, namcos12_state )
 	/* sound hardware */
 	MCFG_SPEAKER_STANDARD_STEREO("lspeaker", "rspeaker")
 
-	MCFG_C352_ADD("c352", 16737350*1.5 ) // ?
+	MCFG_C352_ADD("c352", 16737350*1.5 ) // measured at 29.168MHz, but that's too highpitched
 	MCFG_SOUND_ROUTE(0, "rspeaker", 1.00)
 	MCFG_SOUND_ROUTE(1, "lspeaker", 1.00)
 	MCFG_SOUND_ROUTE(2, "rspeaker", 1.00)