diff --git a/libs/architectures/architectures/multimodal_time_split.py b/libs/architectures/architectures/multimodal_time_split.py
new file mode 100644
index 00000000..885dcaf3
--- /dev/null
+++ b/libs/architectures/architectures/multimodal_time_split.py
@@ -0,0 +1,79 @@
+import torch
+import torch.nn as nn
+from architectures.supervised import SupervisedArchitecture
+from ml4gw.nn.resnet.resnet_1d import ResNet1D, NormLayer
+from typing import Optional, Literal
+
+
+class MultimodalTimeSplitSupervisedArchitecture(SupervisedArchitecture):
+    def __init__(
+        self,
+        num_ifos: int,
+        low_time_classes: int,
+        high_time_classes: int,
+        freq_classes: int,
+        low_time_layers: list[int],
+        high_time_layers: list[int],
+        freq_layers: list[int],
+        time_kernel_size: int = 3,
+        freq_kernel_size: int = 3,
+        zero_init_residual: bool = False,
+        groups: int = 1,
+        width_per_group: int = 64,
+        stride_type: Optional[list[Literal["stride", "dilation"]]] = None,
+        norm_layer: Optional[NormLayer] = None,
+        **kwargs,
+    ):
+        super().__init__()
+
+        # Time-domain ResNets
+        self.strain_low_resnet = ResNet1D(
+            in_channels=num_ifos,
+            layers=low_time_layers,
+            classes=low_time_classes,
+            kernel_size=time_kernel_size,
+            zero_init_residual=zero_init_residual,
+            groups=groups,
+            width_per_group=width_per_group,
+            stride_type=stride_type,
+            norm_layer=norm_layer,
+        )
+
+        self.strain_high_resnet = ResNet1D(
+            in_channels=num_ifos,
+            layers=high_time_layers,
+            classes=high_time_classes,
+            kernel_size=time_kernel_size,
+            zero_init_residual=zero_init_residual,
+            groups=groups,
+            width_per_group=width_per_group,
+            stride_type=stride_type,
+            norm_layer=norm_layer,
+        )
+
+        # Frequency-domain ResNet
+        freq_input_channels = int(num_ifos * 3)
+        self.fft_resnet = ResNet1D(
+            in_channels=freq_input_channels,
+            layers=freq_layers,
+            classes=freq_classes,
+            kernel_size=freq_kernel_size,
+            zero_init_residual=zero_init_residual,
+            groups=groups,
+            width_per_group=width_per_group,
+            stride_type=stride_type,
+            norm_layer=norm_layer,
+        )
+
+        embed_dim = high_time_classes + low_time_classes + freq_classes
+        self.classifier = nn.Linear(embed_dim, 1)
+
+    def forward(
+        self, x_low: torch.Tensor, x_high: torch.Tensor, x_fft: torch.Tensor
+    ):
+        low_out = self.strain_low_resnet(x_low)
+        high_out = self.strain_high_resnet(x_high)
+        fft_out = self.fft_resnet(x_fft)
+
+        features = torch.cat([low_out, high_out, fft_out], dim=-1)
+        return self.classifier(features)
\ No newline at end of file
diff --git a/libs/utils/utils/preprocessing.py b/libs/utils/utils/preprocessing.py
index e06e6c78..321137d2 100644
--- a/libs/utils/utils/preprocessing.py
+++ b/libs/utils/utils/preprocessing.py
@@ -254,3 +254,131 @@ def forward(self, x: Tensor) -> Tensor:
         x_fft = torch.cat([x_fft.real, x_fft.imag, inv_asd], dim=1)
 
         return x, x_fft
+    
+class MultiModalTimeSplitPreprocessor(torch.nn.Module):
+    """
+    Preprocess a batch of waveforms for multimodal
+    training with a split time strain domain.
+    This includes whitening the time domain data and
+    calculating the frequency domain data
+    """
+    def __init__(
+        self,
+        kernel_length: float,
+        sample_rate: float,
+        inference_sampling_rate: float,
+        batch_size: int,
+        fduration: float,
+        fftlength: float,
+        augmentor: Optional[Callable] = None,
+        highpass: Optional[float] = None,
+        lowpass: Optional[float] = None,
+        return_whitened: bool = False,
+    ) -> None:
+        super().__init__()
+        self.stride_size = int(sample_rate / inference_sampling_rate)
+        self.kernel_size = int(kernel_length * sample_rate)
+        self.augmentor = augmentor
+        self.return_whitened = return_whitened
+        self.highpass = highpass
+        self.lowpass = lowpass
+        self.fftlength = fftlength
+        self.n_fft = int(fftlength * sample_rate)
+        self.sample_rate = sample_rate
+        self.n_fft_psd = int(fftlength * sample_rate)
+        self.feature_nfft = self.kernel_size
+
+        strides = (batch_size - 1) * self.stride_size
+        fsize = int(fduration * sample_rate)
+        size = strides + self.kernel_size + fsize
+        length = size / sample_rate
+        self.psd_estimator = PsdEstimator(
+            length,
+            sample_rate,
+            fftlength=fftlength,
+            overlap=None,
+            average="median",
+            fast=highpass is not None,
+        )
+        self.whitener = Whiten(fduration, sample_rate, highpass, lowpass)
+
+        freqs = torch.fft.rfftfreq(self.feature_nfft, d=1 / sample_rate)
+        self.freq_mask = torch.ones_like(freqs, dtype=torch.bool)
+        if highpass is not None:
+            self.freq_mask &= freqs > highpass
+        # if lowpass is not None:
+        #     self.freq_mask &= freqs < lowpass
+        self.freqs = freqs
+        self.freq_mask = self.freq_mask
+        self.num_freqs = int(freqs.numel())
+
+    def forward(self, x: Tensor):
+        if x.ndim == 3:
+            num_channels = x.size(1)
+        elif x.ndim == 2:
+            num_channels = x.size(0)
+        else:
+            raise ValueError(f"Unexpected input shape: {x.shape}")
+
+        x, psd = self.psd_estimator(x)
+        whitened = self.whitener(x, psd)
+        whitened_low = self.whitener(
+            x, psd, highpass=self.highpass, lowpass=self.lowpass
+        )
+        whitened_high = self.whitener(
+            x, psd, highpass=self.lowpass, lowpass=None
+        )
+
+        x = x.float()
+
+        asds = psd**0.5
+        asds = asds.float()
+        asds *= 1e23
+
+        # ensure asd is 3D so mask works even if asd is never interpolated
+        if asds.ndim == 2:
+            asds = asds.unsqueeze(0)
+
+        # unfold x and other inputs and then put into expected shape.
+        # Note that if x has both signal and background
+        # batch elements, they will be interleaved along
+        # the batch dimension after unfolding
+        x = unfold_windows(whitened, self.kernel_size, self.stride_size)
+        x_low = unfold_windows(
+            whitened_low, self.kernel_size, self.stride_size
+        )
+        x_high = unfold_windows(
+            whitened_high, self.kernel_size, self.stride_size
+        )
+        x = x.reshape(-1, num_channels, self.kernel_size)
+
+        x_fft = torch.fft.rfft(x, n=self.feature_nfft, dim=-1)
+        F_expected = self.num_freqs
+        F_actual = x_fft.shape[-1]
+        if F_actual != F_expected:
+            raise ValueError(
+                f"""FFT bin mismatch: got F={F_actual} from rfft," \
+                 expected {F_expected}"""
+                f"(kernel_size={self.kernel_size}, n_fft={self.n_fft}). "
+                "Ensure fftlength*sample_rate matches the " \
+                "intended kernel-length FFT."
+            )
+
+        asds = torch.nn.functional.interpolate(
+            asds,
+            size=(self.num_freqs,),
+            mode="linear",
+        )
+
+        asds = asds[:, :, self.freq_mask]
+        inv_asd = 1 / asds
+        inv_asd = inv_asd.repeat(x_fft.shape[0], 1, 1)
+        x_fft = x_fft[..., self.freq_mask]
+
+        x_fft = torch.cat([x_fft.real, x_fft.imag, inv_asd], dim=1)
+
+        x_low = x_low.reshape(-1, num_channels, self.kernel_size)
+        x_high = x_high.reshape(-1, num_channels, self.kernel_size)
+        x_fft = x_fft.reshape(x_low.shape[0], -1, x_fft.shape[-1])
+
+        return x_low, x_high, x_fft
diff --git a/projects/train/train/data/supervised/__init__.py b/projects/train/train/data/supervised/__init__.py
index 4ca80c17..ab559bde 100644
--- a/projects/train/train/data/supervised/__init__.py
+++ b/projects/train/train/data/supervised/__init__.py
@@ -3,5 +3,6 @@
     SpectrogramDomainSupervisedAframeDataset,
 )
 from .multimodal import MultiModalSupervisedAframeDataset
+from .multimodal_time_split import MultimodalTimeSplitSupervisedAframeDataset
 from .supervised import SupervisedAframeDataset
 from .time_domain import TimeDomainSupervisedAframeDataset
diff --git a/projects/train/train/data/supervised/multimodal_time_split.py b/projects/train/train/data/supervised/multimodal_time_split.py
new file mode 100644
index 00000000..b47153c4
--- /dev/null
+++ b/projects/train/train/data/supervised/multimodal_time_split.py
@@ -0,0 +1,156 @@
+from typing import Optional
+import torch
+import torch.nn.functional as F
+from train.data.supervised.supervised import SupervisedAframeDataset
+
+
+class MultimodalSupervisedAframeDataset(SupervisedAframeDataset):
+    def __init__(
+        self,
+        *args,
+        swap_prob: Optional[float] = None,
+        mute_prob: Optional[float] = None,
+        **kwargs,
+    ) -> None:
+        super().__init__(
+            *args, swap_prob=swap_prob, mute_prob=mute_prob, **kwargs
+        )
+
+    @torch.no_grad()
+    def augment(self, X, waveforms):
+        X, y, psds = super().augment(X, waveforms)
+
+        psds = psds
+
+        X_whitened = self.whitener(X, psds)
+        X_low = self.whitener(
+            X,
+            psds,
+            highpass=self.hparams.highpass,
+            lowpass=self.hparams.lowpass,
+        ).float()
+        X_high = self.whitener(
+            X, psds, highpass=self.hparams.lowpass, lowpass=None
+        ).float()
+
+        X_fft = torch.fft.rfft(X_whitened, dim=-1)
+        asds = psds**0.5
+
+        freqs = torch.fft.rfftfreq(
+            X_whitened.shape[-1], d=1 / self.hparams.sample_rate
+        )
+        num_freqs = len(freqs)
+
+        asds = torch.nn.functional.interpolate(
+            asds,
+            size=(num_freqs,),
+            mode="linear",
+        )
+        mask = torch.ones_like(freqs, dtype=torch.bool)
+        if self.hparams.highpass is not None:
+            mask &= freqs > self.hparams.highpass
+        # if self.hparams .lowpass is not None:
+        #    mask &= freqs < self.hparams.lowpass
+
+        asds = asds[:, :, mask]
+        asds *= 1e23
+        inv_asds = 1 / asds
+
+        X_fft = X_fft[:, :, mask]
+        X_fft = torch.cat([X_fft.real, X_fft.imag, inv_asds], dim=1).float()
+        if torch.isnan(X_low).any() or torch.isinf(X_low).any():
+            raise ValueError("NaN or Inf in X_low")
+        if torch.isnan(X_fft).any() or torch.isinf(X_fft).any():
+            raise ValueError("NaN or Inf in X_fft")
+        if torch.isnan(y).any() or torch.isinf(y).any():
+            raise ValueError("NaN or Inf in y")
+
+        return X_low, X_high, X_fft, y.float()
+
+    def on_after_batch_transfer(self, batch, _):
+        """
+        Perform on-device preprocessing after transferring batch to device.
+
+        Augments data during training and injects signals into background during validation,
+        performing whitening and FFT-based preprocessing.
+        """
+        if self.trainer.training:
+            # Training mode: perform random augmentations using waveforms
+            [X], waveforms = batch
+            return self.augment(X, waveforms)
+
+        elif self.trainer.validating or self.trainer.sanity_checking:
+            # Validation mode: prepare signal-injected validation batches
+            [background, _, timeslide_idx], [signals] = batch
+            if isinstance(timeslide_idx, torch.Tensor):
+                timeslide_idx = timeslide_idx[0].item()
+            shift = float(self.timeslides[timeslide_idx].shift_size)
+
+            # Build validation inputs and corresponding PSDs
+            X_bg, X_inj, psds = super().build_val_batches(background, signals)
+
+            # Background: low/high-passed and FFT-processed
+            X_bg_whitened = self.whitener(X_bg, psds)
+            X_bg_low = self.whitener(
+                X_bg,
+                psds,
+                highpass=self.hparams.highpass,
+                lowpass=self.hparams.lowpass,
+            ).float()
+            X_bg_high = self.whitener(
+                X_bg, psds, highpass=self.hparams.lowpass, lowpass=None
+            ).float()
+            X_bg_fft = torch.fft.rfft(X_bg_whitened)
+
+            # Foreground: process injected signals similarly
+            X_fg_whitened, X_fg_low, X_fg_high = [], [], []
+            for inj in X_inj:
+                X_fg_low.append(
+                    self.whitener(
+                        inj,
+                        psds,
+                        lowpass=self.hparams.lowpass,
+                        highpass=self.hparams.highpass,
+                    ).float()
+                )
+                X_fg_high.append(
+                    self.whitener(
+                        inj, psds, lowpass=None, highpass=self.hparams.lowpass
+                    ).float()
+                )
+                X_fg_whitened.append(self.whitener(inj, psds))
+            X_fg_low = torch.stack(X_fg_low)
+            X_fg_high = torch.stack(X_fg_high)
+            X_fg_whitened = torch.stack(X_fg_whitened, dim=0)
+            X_fg_fft = torch.fft.rfft(X_fg_whitened)
+
+            asds = psds**0.5
+            asds *= 1e23
+            asds = asds.float()
+            num_freqs = X_fg_fft.shape[-1]
+            if asds.shape[-1] != num_freqs:
+                asds = F.interpolate(asds, size=(num_freqs,), mode="linear")
+            inv_asds = 1 / asds
+
+            X_bg_fft = torch.cat(
+                [X_bg_fft.real, X_bg_fft.imag, inv_asds], dim=1
+            ).float()
+            inv_asds = inv_asds.unsqueeze(0).repeat(5, 1, 1, 1)
+            X_fg_fft = torch.cat(
+                [X_fg_fft.real, X_fg_fft.imag, inv_asds], dim=2
+            ).float()
+
+            # Return data grouped into background and injected signal components
+            return (
+                shift,
+                X_bg_low,
+                X_bg_high,
+                X_bg_fft,
+                X_fg_low,
+                X_fg_high,
+                X_fg_fft,
+                psds,
+            )
+
+        # Default: return batch unchanged
+        return batch
\ No newline at end of file
diff --git a/projects/train/train/model/__init__.py b/projects/train/train/model/__init__.py
index 5bbd13d3..d127ce48 100644
--- a/projects/train/train/model/__init__.py
+++ b/projects/train/train/model/__init__.py
@@ -4,4 +4,5 @@
     SupervisedAframe,
     SupervisedAframeS4,
     SupervisedMultiModalAframe,
+    SupervisedMultiModalTimeSplitAframe,
 )
diff --git a/projects/train/train/model/supervised.py b/projects/train/train/model/supervised.py
index 5fe42b24..7088895f 100644
--- a/projects/train/train/model/supervised.py
+++ b/projects/train/train/model/supervised.py
@@ -126,3 +126,73 @@ def configure_optimizers(self):
         scheduler_config = {"scheduler": scheduler, "interval": "step"}
 
         return {"optimizer": optimizer, "lr_scheduler": scheduler_config}
+
+class SupervisedMultimodalTimeSplitAframe(AframeBase):
+    def __init__(
+        self,
+        arch: SupervisedArchitecture,
+        *args,
+        **kwargs,
+    ) -> None:
+        super().__init__(arch, *args, **kwargs)
+
+    def forward(self, x_low: Tensor, x_high: Tensor, x_fft: Tensor) -> Tensor:
+        return self.model(x_low, x_high, x_fft)
+
+    def train_step(self, batch: tuple) -> Tensor:
+        # Unpack depending on number of elements
+        if len(batch) != 4:
+            raise ValueError(
+                f"Unexpected batch format in train_step: {len(batch)} elements"
+            )
+
+        X_low, X_high, X_fft, y = batch
+
+        y_hat = self(X_low, X_high, X_fft).squeeze(-1)
+        # Match shape of y_hat
+        y = y.float().view_as(y_hat)
+        return F.binary_cross_entropy_with_logits(y_hat, y)
+
+    def score(self, X):
+        X_low, X_high, X_fft = X
+        return self.model(X_low, X_high, X_fft).squeeze(-1)
+
+    def validation_step(self, batch, batch_idx):
+        try:
+            shift, X_bg, X_inj = batch
+        except ValueError:
+            (
+                shift,
+                X_bg_low,
+                X_bg_high,
+                X_bg_fft,
+                X_fg_low,
+                X_fg_high,
+                X_fg_fft,
+                *_,
+            ) = batch
+            X_bg = (X_bg_low, X_bg_high, X_bg_fft)
+            X_inj = (X_fg_low, X_fg_high, X_fg_fft)
+
+        # Score background
+        y_bg = self.score(X_bg)
+
+        # Score injected signals
+        x0 = X_inj[0]
+        if x0.ndim >= 4:
+            V, B = x0.shape[:2]
+            x_flat = tuple(x.reshape(V * B, *x.shape[2:]) for x in X_inj)
+            y_fg = self.score(x_flat).view(V, B).mean(0)
+        else:
+            y_fg = self.score(X_inj)
+
+        shift_val = float(shift) if not isinstance(shift, float) else shift
+        self.metric.update(shift_val, y_bg, y_fg)
+
+        self.log(
+            "valid_auroc",
+            self.metric,
+            on_step=True,
+            on_epoch=True,
+            sync_dist=True,
+        )
\ No newline at end of file