diff --git a/src/devices/sound/swp00.cpp b/src/devices/sound/swp00.cpp
index d2a3818f36e..2aabf9f06fc 100644
--- a/src/devices/sound/swp00.cpp
+++ b/src/devices/sound/swp00.cpp
@@ -321,7 +321,6 @@ void swp00_device::device_start()
 
 	save_item(NAME(m_lfo_phase));
 	save_item(NAME(m_sample_pos));
-	save_item(NAME(m_sample_increment));
 	save_item(NAME(m_envelope_level));
 
 	save_item(NAME(m_glo_level_cur));
@@ -340,6 +339,10 @@ void swp00_device::device_start()
 	save_item(NAME(m_decay_done));
 	save_item(NAME(m_lpf_done));
 
+	save_item(NAME(m_dpcm_current));
+	save_item(NAME(m_dpcm_next));
+	save_item(NAME(m_dpcm_address));
+
 	for(int i=0; i != 128; i++) {
 		u32 v = 0;
 		switch(i >> 3) {
@@ -353,24 +356,12 @@ void swp00_device::device_start()
 		m_global_step[i] = v;
 	}
 
-	// Log to linear 8-bits sample decompression.  Statistics say
-	// that's what it should look like.  Note that 0 can be encoded
-	// both as 0x00 and 0x80, and as it happens 0x80 is never used in
-	// these samples.  Ends up with a 55dB dynamic range, to compare
-	// with 8bits 48dB, 12bits 72dB and 16bits 96dB.
+	// Delta-packed samples decompression.
 
-	//  Rescale so that it's roughly 16 bits.  Range ends up being +/- 78c0.
-
-	for(int i=0; i<32; i++) {
-		m_sample_log8[     i] =  i << 0;
-		m_sample_log8[0x20|i] = (i << 1) + 0x21;
-		m_sample_log8[0x40|i] = (i << 2) + 0x62;
-		m_sample_log8[0x60|i] = (i << 3) + 0xe3;
-	}
 	for(int i=0; i<128; i++) {
-		s16 base = m_sample_log8[i] << 6;
-		m_sample_log8[i | 0x80] = - base;
-		m_sample_log8[i]        = + base;
+		s16 base = ((i & 0x1f) << (7+(i >> 5))) + (((1 << (i >> 5))-1) << 12);
+		m_dpcm[i | 0x80] = - base;
+		m_dpcm[i]        = + base;
 	}
 }
 
@@ -465,7 +456,6 @@ void swp00_device::device_reset()
 
 	std::fill(m_lfo_phase.begin(), m_lfo_phase.end(), 0);
 	std::fill(m_sample_pos.begin(), m_sample_pos.end(), 0);
-	std::fill(m_sample_increment.begin(), m_sample_increment.end(), 0);
 	std::fill(m_envelope_level.begin(), m_envelope_level.end(), 0);
 
 	std::fill(m_glo_level_cur.begin(), m_glo_level_cur.end(), 0);
@@ -483,6 +473,10 @@ void swp00_device::device_reset()
 	std::fill(m_decay.begin(), m_decay.end(), false);
 	std::fill(m_decay_done.begin(), m_decay_done.end(), false);
 	std::fill(m_lpf_done.begin(), m_lpf_done.end(), false);
+
+	std::fill(m_dpcm_current.begin(), m_dpcm_current.end(), false);
+	std::fill(m_dpcm_next.begin(), m_dpcm_next.end(), false);
+	std::fill(m_dpcm_address.begin(), m_dpcm_address.end(), false);
 }
 
 void swp00_device::rom_bank_pre_change()
@@ -914,6 +908,10 @@ void swp00_device::keyon(int chan)
 	m_decay[chan] = false;
 	m_decay_done[chan] = false;
 
+	m_dpcm_current[chan] = 0;
+	m_dpcm_next[chan] = 0;
+	m_dpcm_address[chan] = m_sample_address[chan] - m_sample_start[chan];
+
 	m_lpf_value[chan] = m_lpf_target_value[chan];
 	m_lpf_timer[chan] = 0x4000000;
 	m_lpf_ha[chan] = 0;
@@ -1278,21 +1276,21 @@ void swp00_device::sound_stream_update(sound_stream &stream, std::vector<read_st
 			case 0: { // 16-bits linear
 				offs_t adr = base_address + (spos << 1);
 				val0 = read_word(adr);
-				val1 = read_word(adr+1);
+				val1 = read_word(adr+2);
 				break;
 			}
 
 			case 1: { // 12-bits linear
 				offs_t adr = base_address + (spos >> 2)*6;
 				switch(spos & 3) {
-				case 0: { // .abc .... ....
+				case 0: { // Cabc ..AB .... ....
 					u16 w0 = read_word(adr);
 					u16 w1 = read_word(adr+2);
 					val0 = (w0 & 0x0fff) << 4;
 					val1 = ((w0 & 0xf000) >> 8) | ((w1 & 0x00ff) << 8);
 					break;
 				}
-				case 1: { // C... ..AB ....
+				case 1: { // c... BCab ...A ....
 					u16 w0 = read_word(adr);
 					u16 w1 = read_word(adr+2);
 					u16 w2 = read_word(adr+4);
@@ -1300,14 +1298,14 @@ void swp00_device::sound_stream_update(sound_stream &stream, std::vector<read_st
 					val1 = ((w1 & 0xff00) >> 4) | ((w2 & 0x000f) << 12);
 					break;
 				}
-				case 2: { // .... bc.. ...a
+				case 2: { // .... bc.. ABCa ....
 					u16 w1 = read_word(adr+2);
 					u16 w2 = read_word(adr+4);
 					val0 = ((w1 & 0xff00) >> 4) | ((w2 & 0x000f) << 12);
 					val1 = w2 & 0xfff0;
 					break;
 				}
-				case 3: { // .... .... ABC.
+				case 3: { // .... .... abc. .ABC
 					u16 w2 = read_word(adr+4);
 					u16 w3 = read_word(adr+6);
 					val0 = w2 & 0xfff0;
@@ -1323,11 +1321,23 @@ void swp00_device::sound_stream_update(sound_stream &stream, std::vector<read_st
 				val1 = (read_byte(base_address + spos + 1) << 8);
 				break;
 
-			case 3:   // 8-bits logarithmic
-				val0 = m_sample_log8[read_byte(base_address + spos)];
-				val1 = m_sample_log8[read_byte(base_address + spos + 1)];
+			case 3: { // 8-bits logarithmic
+				u32 target_address = base_address + spos + 1;
+				while(m_dpcm_address[chan] <= target_address) {
+					m_dpcm_current[chan] = m_dpcm_next[chan];
+					s32 sample = m_dpcm_next[chan] + m_dpcm[read_byte(m_dpcm_address[chan])];
+					m_dpcm_address[chan] ++;
+					if(sample < -0x8000)
+						sample = -0x8000;
+					else if(sample > 0x7fff)
+						sample = 0x7fff;
+					m_dpcm_next[chan] = sample;
+				}
+				val0 = m_dpcm_current[chan];
+				val1 = m_dpcm_next[chan];
 				break;
 			}
+			}
 
 			s32 mul = m_sample_pos[chan] & 0x7fff;
 			s32 sample = (val1 * mul + val0 * (0x8000 - mul)) >> 7;
@@ -1363,9 +1373,11 @@ void swp00_device::sound_stream_update(sound_stream &stream, std::vector<read_st
 				if(!m_sample_end[chan])
 					m_active[chan] = false;
 				else {
+					s32 prev = m_sample_pos[chan];
 					do
 						m_sample_pos[chan] -= (m_sample_end[chan] << 15) | ((m_sample_dec_and_format[chan] & 0x3f) << 9);
 					while((m_sample_pos[chan] >> 15) >= m_sample_end[chan]);
+					m_dpcm_address[chan] += (m_sample_pos[chan] >> 15) - (prev >> 15);
 				}
 			}
 
diff --git a/src/devices/sound/swp00.h b/src/devices/sound/swp00.h
index 36dfba1677d..21b7b384085 100644
--- a/src/devices/sound/swp00.h
+++ b/src/devices/sound/swp00.h
@@ -43,7 +43,7 @@ private:
 	static const std::array<s32, 0x20> decay_linear_step;
 	static const std::array<s32, 16> panmap;
 	std::array<s32, 0x80> m_global_step;
-	std::array<s16, 0x100> m_sample_log8;
+	std::array<s16, 0x100> m_dpcm;
 
 	static const std::array<u32, 4> lfo_shape_centered_saw;
 	static const std::array<u32, 4> lfo_shape_centered_tri;
@@ -83,7 +83,6 @@ private:
 
 	std::array<u32, 0x20>  m_lfo_phase;
 	std::array<s32, 0x20>  m_sample_pos;
-	std::array<u32, 0x20>  m_sample_increment;
 	std::array<s32, 0x20>  m_envelope_level;
 	std::array<s32, 0x20>  m_glo_level_cur;
 	std::array<s32, 0x20>  m_pan_l;
@@ -95,6 +94,9 @@ private:
 	std::array<s32, 0x20>  m_lpf_ha;
 	std::array<s32, 0x20>  m_lpf_hb;
 	std::array<bool, 0x20> m_active, m_decay, m_decay_done, m_lpf_done;
+	std::array<s16, 0x20>  m_dpcm_current;
+	std::array<s16, 0x20>  m_dpcm_next;
+	std::array<u32, 0x20>  m_dpcm_address;
 
 	u16 m_waverom_val;
 	u8 m_waverom_access;