implemented volume, taitognet sounds pretty good now, still need to find out why taitofx1b sound sucks compared to it, especially raystorm

src/emu/sound/zsg2.c

@@ -44,13 +44,11 @@
 
     ---------------------------------------------------------
 
-Emulation is still preliminary.
-
 TODO:
-- channel volume, 16bits?? need to make a lookup table?
-- some samples are in stereo format?
+- volume/panning is linear?
+- what is reg 0xa/0xc? seems related to volume
+- identify sample flags
 - memory reads out of range sometimes
-- a lot of unknowns
 
 */
 
@@ -110,6 +108,7 @@ void zsg2_device::device_start()
 		save_item(NAME(m_chan[ch].loop_pos), ch);
 		save_item(NAME(m_chan[ch].page), ch);
 		save_item(NAME(m_chan[ch].vol), ch);
+		save_item(NAME(m_chan[ch].flags), ch);
 		save_item(NAME(m_chan[ch].panl), ch);
 		save_item(NAME(m_chan[ch].panr), ch);
 	}
@@ -217,17 +216,14 @@ void zsg2_device::sound_stream_update(sound_stream &stream, stream_sample_t **in
 				m_chan[ch].samples = prepare_samples(m_chan[ch].page | m_chan[ch].cur_pos);
 			}
 			
-			INT16 sample = m_chan[ch].samples[m_chan[ch].step_ptr >> 16 & 3];
-			
-			//sample = (sample * (m_chan[ch].vol & 0xffff)) / 0x10000;
-			if (m_chan[ch].vol == 0) sample = 0; // temp hack to prevent stuck notes
+			INT32 sample = (m_chan[ch].samples[m_chan[ch].step_ptr >> 16 & 3] * m_chan[ch].vol) >> 16;
 			
 			mix_l += (sample * m_chan[ch].panl + sample * (0x1f - m_chan[ch].panr)) >> 5;
 			mix_r += (sample * m_chan[ch].panr + sample * (0x1f - m_chan[ch].panl)) >> 5;
 		}
 
-		outputs[0][i] = mix_l / 48;
-		outputs[1][i] = mix_r / 48;
+		outputs[0][i] = mix_l;
+		outputs[1][i] = mix_r;
 	}
 }
 
@@ -293,10 +289,15 @@ void zsg2_device::chan_w(int ch, int reg, UINT16 data)
 			break;
 		
 		case 0xe:
-			// channel volume, reg 0xa/0xc is also related?
+			// volume
 			m_chan[ch].vol = data;
 			break;
 		
+		case 0xf:
+			// flags
+			m_chan[ch].flags = data;
+			break;
+		
 		default:
 			break;
 	}
@@ -346,7 +347,7 @@ void zsg2_device::control_w(int reg, UINT16 data)
 
 		case 0x04: case 0x05: case 0x06:
 		{
-			// key off?
+			// key off
 			int base = (reg & 3) << 4;
 			for (int i = 0; i < 16; i++)
 			{

src/emu/sound/zsg2.h

@@ -59,6 +59,7 @@ private:
 		UINT32 loop_pos;
 		UINT32 page;
 		UINT16 vol;
+		UINT16 flags;
 		UINT8 panl;
 		UINT8 panr;
 	};

src/mame/audio/taito_zm.c

@@ -24,9 +24,8 @@ and a Zoom Corp. ZFX-2 DSP instead of the TMS57002.
 
 
 TODO:
-- add TMS57002
-- global volume regs
-- a lot more
+- add DSP, sound is tinny without it
+- howcome taito fx1b sounds worse than gnet? especially raystorm
 
 ***************************************************************************/
 
@@ -44,6 +43,7 @@ const device_type TAITO_ZOOM = &device_creator<taito_zoom_device>;
 taito_zoom_device::taito_zoom_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
 	: device_t(mconfig, TAITO_ZOOM, "Taito Zoom Sound System", tag, owner, clock, "taito_zoom", __FILE__),
 	m_soundcpu(*this, ":mn10200"),
+	m_zsg2(*this, ":zsg2"),
 	m_reg_address(0),
 	m_tms_ctrl(0)
 {
@@ -143,11 +143,17 @@ WRITE16_MEMBER(taito_zoom_device::reg_data_w)
 	switch (m_reg_address)
 	{
 		case 0x04:
-			// zsg2+dsp global volume ch0
+			// zsg2+dsp global volume left
+			if (data & 0xc0c0)
+				popmessage("ZOOM gain L %04X, contact MAMEdev", data);
+			m_zsg2->set_output_gain(0, (data & 0x3f) / 63.0);
 			break;
 		
 		case 0x05:
-			// zsg2+dsp global volume ch1
+			// zsg2+dsp global volume right
+			if (data & 0xc0c0)
+				popmessage("ZOOM gain R %04X, contact MAMEdev", data);
+			m_zsg2->set_output_gain(1, (data & 0x3f) / 63.0);
 			break;
 
 		default:

src/mame/audio/taito_zm.h

@@ -30,6 +30,7 @@ private:
 	
 	// devices/pointers
 	required_device<mn10200_device> m_soundcpu;
+	required_device<zsg2_device> m_zsg2;
 	
 	// internal state
 	UINT16 m_reg_address;